fed-std-h28-2b

7/14/2019 FED-STD-H28-2B

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FEFSTD-E28/2S20 AqJst 1991SUPEI?SEDItG

FED-STD-F128/2A20 April1984

(seeNote)

FEDERALTANDARD

SCREW- THREADTANDARDSFOR FEDERALSERVICES

SECTION

UHIFIEDNCHSCREWMEADS-

UNANDUt14RHREADORMS

This standardwas approvedby theCkxmnissioner,ederalSupplySsrvice,GeneralServicesAdministration,for theuseof al-lEkderalagencies.

AMc m APEA1’ms

DISTFUW1’ION~ A. -Approvedforpublicrelease; distrikxkionis unlimit

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This FederalStadard is issuedin lwsel.eaf formto permitthe insertion

or removalof new or revisedpagesard sections.

All usersof FederalStadards stculdkeep themup todate by inserting

revisedor new pagesaa issued* removingsu~seded ad canceledpages.

w ad revisedpageswill be issti tier ChangeNoticeswhichwill benunberedcmsecutivelyad willbear the dateof issuance. ChangeNotices

shouldbe retainedd filedin frontof tk stadard untilsuch timeas theyare s~rseded by a reissueof the entirestardard.

EtnawmI,., ,

This secticnwas develqed b provideUnified InchScrewThreadabr theFederalServices. It Q formxly kmwn as “UnifiedThreadI@rm ad ThreadSeriesforBolts,.!kretrs,uts,Ta~ BolesaM GeneralAppli=tions=.EEWS1’&H28/2Aws a Ca@ete revision of FR%7TWB28/2 dated 31 March 2978.It added the nsiterialreviouslyidentifiedas FfD-sTD-H28\3dated

31 March 1978,whichwas knownas “UnifiedThreadaof SpecialDianeters,Pitches,.d Lengthsof Engagenx2nt”.&terial franAppmdices A3 ad AS ofFED+IWB28 dated 31 March 1978was revisedad tecaueApprdies A and B,respectively,f FBD-STD-E28/2A.

.,,...,, .,,,....:, ,, ,. .,.. .. ..... ,.,

FSD-51WH28/2Awas preparedby tk CefenseIndustrialSup@y Center ~-IS)and inoxpxated theAmericanNeticnalStardsrdb’ UnitiedInchScrewThreads,WI B1.1-1982. Significzmtchangesfranthe previousissuesincltiedthe

following(1) AddedUNR, externalthreadformwith mandatoryroundedrrnt.(2) Sevisedtolerancerequirementsfor leadand flankangles.(3) Addedrequirementstir controlof surfacetixture,cknfers, ad rolle

threadled-ins ad run-outs.(4) Addedrequirementthat inspectionmethodsfor acceptabilityare in

aaxmdance witb FER51D-H28/20.

FED-STWH28/2BincorporatestheAmericanNationalStandardfor IJnifed InchScrewThreads,A.SNZB1.1-1989whichsuperssdsdA!W B1.1-1982and its

suPPl~t , At=z B1.1s-1984. It @ates theFEE.S’K)-H28/2Aated 20 April

1984ad improvesthe legibilityof the tables. ~ndix C was .dded toprovideinfonnaticmalxmt tk obsoluteAmrican Naticna3formthreads.

ii

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FED-sl’D-H28/2s

SETIOW 2 - UnifiedInchScrewThreads-

UW ard UNR ThreadFOrIUS

1- ~ ~is ~tion providesthe standardfor WIified inch~rewthreadsto be usedby the FederalServices.

1.1 ,Qm.itations.(My uw ad UWR screw threadsare cmered in thissection. Ebr UNl threads(axkrolledexternalthreadrouded root withincreasedbasicminordiamter) see FED-STD-H28/4(MIL-S-8879. For UN!threads(miniaturethreada)aee FEO+lD-H28/5.

1.2 Application.

1.2.1 UW formscrewthreads. The uw threadis intendedfor generalpurpofastening~~i-G; Its externalthreadrootmay be either flatorrourikd.

1.2.2 UWR formscrqg i+reads. The UN’Sforma@ies mly to externalthreads. Y&~l~&n IS the sa.m as thatof the external UN thread excepthatthe rcot is requiredto be rourxled.UNR threadsare appliednmt often ‘high volum annnercialfastenerthreadsproducedby rolling.

Nnz: The uardatiryroumiedrcotof the UNR threadgreatlyreducesthe wn02ntrationof stress,knee increasesthe fatiguelif

of threadedpr ta.

2. Referenceddcmnrents.——. —

2.1 Governxren~uMications. The issuesof * following&amenta in..—effecton the date of—invitationfor bids or rsquestforprqosal km a partof thisstandardto theextent~cified &rein.

FederalStadards...- ——-—

FElE71EH28/1 - Nxrenclatue,Definitionsand LetterSymkmlsforScrewThreads

FED-S’IEE28/6- Gagesti GagingforUnifiedScrew Threads

FED-SlWS28/20- InspectionM?tkds forAcceptabili& of UW, ONR,UNJ, M and Ml Screw-Threads

(Activitiesoutsidethe FederalGmernnent my obtaincopies of Federalspecifications,tardards,and ccaurercialtemdescriptionsas outlinedurileGeneralInformationin the In5exof FederalSpecifications,%an5ards,adCrammsrcialtem Oescriptions. The Index,which includescumulativebi-nnnthl

SU@SIEntS as issued,is for saleon a subscriptionbasisby the Superinten+ent of Dccunenta,U.S.GovernmentPrintingOffice,Washington,IX 20402.

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FIm-s13H128/2B

(Singlempies of thisstandardandotherF&eral specificatims, standardsad cwmercial itemdescriptionsrequiredby activitiesoutsidetheFederal

@vernment for biddingp~ses are availablefrcxnthe GeneralServicesAdministrationSpecificationSection,Ftxxn6654,7th ard D Streets,S.W.,Washington,CC 20407;telepimw?(202)708-9205.

(FederalC%vermrentactivitiesmay obtainaypiesof F@deralstardardization

documnts, ad the Indexof FederalSpecifications,tandards,and(kxnnercialItemEescripticmsfran-est?bliskldistribution@nts in theiragencies.

2.2 Otherpublicatims. ‘Illsollowingdocummts forma part of thisstarxlardo the extent~ified herein. Unlessa specificissueisidentified,the issuein effectm dateof invitationfor bidsor requestforpropaal shallapply.

Ameri- Watimal Standards.

?@E El.1-1989 - Dnified InchScrewThreads (LIWad ONR Thread

mm)

AMI/ASMZ B46.1- SurfaceTexture- SurfaceFImghneas,wavinessandLay

(A@icatia forrxpiesshouldte a&3ressedto theAmericanSocietyofWchanical Engineers,UnitedEngineeringCenter,345Eakt 47thStreet,Wew York,WY 10017or theArericanNatimal StsndsrdsInstitute,H West 42ndStreet,Wew York,WY 10036.)

3. Definitions.The termsa~licable to thisstandardare definedinEEEsm-B2&/l .

4. Generalrequiremnts.

4.1 Screw threads. Unifiedinchscrewthreadssbal.1@ in,arxxx&ce withASMS B1.1-1989ad thisFederalStarderd. QilyStam3ardSeries UnifiedScrewl%rezxls,istedinTable 3A of ASMEB1.1-1989,shallbe usedfor new designforthe FederalServicesunlesspriorapprovalhas beengrantedby theprmxreuentautlxxi~ to deviatefrom them. Coxae ad finethreadseriesare preferred.

4.2 AcceptabilityScrew threadinspectionmetl-dsfor acceptabilityhalllxsin arxxxdancewi~ E’ED-SD+328/20.The requiredgagingsystemshallbe

specifiedin accordancewith thatstandard.

4.3 Gaqesad gaginq. Gagesand gagingshallbe in accordancewithFE&51D-H28/6.

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5.1 Diamter~itch mubinations. When standardsize screwthreadsreferredto..n.4.l.canno.t..lz2.sed,..be.designez..kcddddhaos.e+referred.siz=sf.-ti’yeadsisl@ in ‘1’@.leB of M B1.1-3.989.lf this is,not pssible,

onsiderationslxxidbe gi.yento the folbi.ng sub-paragraphsin the choi~ ofthread.

5.1.1 Preferredrun-standarddiameters. tb?neverpossible,‘& ~diamter stwuldbe selectedEran seriesof dimretarincrementsas follows:

Diauk?terange

inch

0.25 to 0.6stove 0.6 to 1.5

abve 1.5 to 6.0stove 6 to16

akove16w24

Firstchoice

increlent

inch

0.050.1

0.250.5

1.0

Second&sireincreumt

inch

—

.0.05

0.10.250.5

It is rewmrendd thatdianetersless than 0.25 inchanform b the standardsizesaa there is virtucdlyno necessityfmr the selectionof a diameternotinclded in * sizes. A.1.eo,+? ax.rseand fine thread series provideamplechoiceof‘diamstet-pitchcmbinatkms. -

5.1.2 Preferrednrn-standardpitches. 14kneverpossible,ti pitch shouldbe selectedfrcxoaae of the following: 40, 36, 32, 28, 24, 20, 16, 12, 10, 8,6and4threada per inch. Intermediatepitdieaalx3uMb usedonly when

absolutelynecessary. Pitchesccarserthan4 threadsper imh are notrecxxmnmded.The curvesslx%n in Figure2.B.2of -ix B cover thepracticaldiaueterlimitssuggestedfor each pi@.

5.2 Threadclassselectia. StandardUnifiedthreadclassesand their

applicat~ection 4 of rk5MEB1.1-3989. when selectingathreadclass,considerationskxd-dfirstbe given b & use of a class ~externalthreadwith a.c3.aas28 internalthreadsince theseclassesaredesignedfor generaluse. Before specifyingclass 3M3B series,it met beconsideredwhethertheadditionalproductkm mst, necessaryfix the tighterfit and toleranm is justified. If a fit Imser than the sbndard class NIB

is required,* rm~referred classIAR may be .spsifiedfor an external

threadof 16 threadsper inch and marser. This specialclassombines thelargerallowanceof theold AmericanNationalclass1 threadwith theUnified

classn toleranm. See 5.2.2 for classN al.lmenm.

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FEFS1’Mi28/2B

5.2.1 Replacementsfor &solete AmericanNationalthreadclasses. Whenthreadsspecifiedwith the obsoleteAmericanNationalthreadclassesare to be

replacedby unifiedthreads,the followingguidelinesare provided:

a. AmericanNationalclass1 coarsethreadsizes (tK!-l)s approxi-matelyequivalentto UnifiedclassIl@l series. C3.aSs1 fine

threadseries (N&l) is approximatelyquivalent dirn?nsionallyoUnifiedclass 2A/2Bseries. StandardUnifiedseriesthreads

should~, consideredprior bJ approvalof replacxznenty rzm-sta!xiardhreads.

b. Amrican Natirnalclass 2 rrarsethreadseries (K-2), 8 thread

series (EN-2), 12 threadseries (12N-2) 16 threadseries (MN-2),ad extra finethreadseries (NEF-2)are mxt nearlyequivalent

to Unifiedseries13N2-21@, 8UN-2@B, 12Ut+2A/Z, 16UN-2A/Zad UNEF-2A/Z3,respectively.Class 2 finethreadseries(W-2)is approximatelyequivalentdimensionallyto Unifiedclass 3A/3B

series, but the use of class 2?@3 series should be omsidered

prior to approvalof replacementby class3A/3B.

c. AmericanNationalclass3 seriesK-3, NY-3,FIEF-3,EN-3,12N-3and 16N-3are nest nearlyequivalentb Unifiedclass3 seriesUN2-3A/3B,UNF-3A/3B,UNEF-3#3S, 8UN-3A/35,12UN-3A/3Bad

16UN-3@B, respectively,

d. There is no Unifiedthreadclassequivalent@ the old AmericanNationalclass 4 whichrequir~ sel~tive fit of ~ts due ti the

pxsibility of interference. “

5.2.2 Threaddbwance~bleranoa . Mbwances and tolerancesspecifiedfor sti~~ Unifiedthreadc.la.ssesre descritedin Secticn5 of A94EB1.1-198

Ebr the spscialexternalthreadclass N, tolerancesare the saneas fir class3A and allowsnce are as follows:

Threadspr inch I ClasslAR allowanm

16141210864

To ccxrplerrentaragraphhole sizelimitsbeforeincltiedin A-d ix A.

inch0.00180.00210.00240.00280.00340.00440.0064

5.6of ?ENE B1.1-1989,reccnmnded tap drill sizes*

threading,fordifferentlengthsof engagement,are

4

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FEo-mB28/2E

5.3 -tion. Designationof Unifiedscrewthreadsis in axordanoe.—with section6 of AWE B1.1-I.989.tkini.na.lize shallbe statedindec~.Tk symtol~ is appli*e to any thread:

. . .. . ., .......

(1) havingthe taaicUnifiedthreadform

and (2) with limit5baseduponUnifiedformulations

arrl (3) which is not in the s~ard serieslistedin Table 3A ofASM?,B1.1-1989.

5.4 Limitsof size. See section8 of IXiMEB1.1-1989for limitsof sizeofstardardandpreferrednm-a~ard threadsand km inbrmation used hr

calculationof nm-stardard threadsize limitswhichare not tabulated.Forclassm, calculateas br clasaIA exceptallowanceis tabulatedin 5.2.2.The followingexanpleillustratest& prccedurenecessaryto alcul.atethelimitsof sizeof a mn-starrhrd thread;this follow-sheoutlinesin tablesIA

and lB of ?x?!MF,1.1-1989:

Externalthread,2.500- 28UtG-2A

Lengthof engagement,1 imh

Maximm major diamter = Mxninalsize - a319wlnce

(section13 of ASkEB.I.1-3989)= 2.5000- 0.0014 (frantable32 of X!& B1.1-1989)= 2.4986

Mininnnnmjor diameter. Mdn’nunmajor diameter- tolerm%e

(section 13 of ASMEB1.1-1989)= 2.4986- 0.0065 (frantible31 of [email protected])

= 2.4921

kiaxinwmitchdiamter = Maxinnnnmajor diamtir - hktable6, CO1. 13 of FtiN8 1.1-1989)

= 2.4986- 0.0232 (rourdedfrcxnO.023197)= 2.4754

Minimumpitchdiameter= M&mum pitch diamter - tolerance(section13 of A94E B1.1-1989)

5 2.4754- 0.0056 (frantable34 of XiFIEB1.1-1989)

= 2.4698

Naninal(mximmn)minordiamter

= WXimm major diamter -?table6, CCL 15 of ASMSB .l-1989)

= 2.4986- 0.0387 (rouded from 0.03866)= 2.4599

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Fm-sImB28/213

Internalthread,2.500- 280N5-2%(b mate with the atrm thread)

Minb.nn&r diaueter. ~ size- 2%(table6; ml; ISofiU3MEB1:l-19S9)

= 12.5000-0.0387(roundedfrom0.03866)

= 2.4613which is rcundadti 2.461

!.laximuminx diaueter= Minim.nninordianeter+ tolerance

(sectim 13 of ISQZ B1.1-3.989)= 2.4613+ 0.0063(frantable39 of ASMEB1.1-1989

forlengthof engagementof O.43)

= 2.4676which is rourdedW 2.468

Minimumpitch diameter= Nminal size- h(table6, ml. 1! of = _B1.1-1989)

= 2.5000- 0.0232 (rourriedrom0.023397

= 2.4768

Maximumpitch diameter= Mininunnitchdiameter+ tilerance

(sectirm13 of ~ B1.1-1989)= 2.4768+ 0.0073 (frrxnie 37 of ASMEB1.1-1989= 2.4841

Mdna.1 (minim@ major= Minimum sizediameter

= 2.5000

Factorsused in the designof threada,particularlyspecialthreads,arepresentedin -ix B. It is to be notedthatdeviationsfrcanstiard

~ler-s for majordiamter of the externalthreadard forminordi.amterofinternalthrerdmay be necessaryin order to arriveat th optimumdesign.

5.5 Surfacetexture.

5.5.1 l!he~ sbiillhavea smoth finishend te freefirm flawsand

otherdefects,suches fins,nicksand burrs,thatwouldmake themunsuitablefor * purpae intended.

5.5.2 Wdonanahip shallbe rrmaistentwith the &Jeranms specified

herein. Surfacetextureof threadsprodumd b thisstamiardshallnot exceed100 microincharit.beticalaverageroughness (~) for at threads ~ 63microinch(~) for rolledard groud threadsin ar- with AISI/M?4Z

B46.1.

WE: c2xrsead finepitch threadswith xoughsurfacetextureare tmre likely

b cross-thread.Threadswith chamferedenteringendshave theleasttendency

to cross-threadwhen assembledwith pwer tmls.

6

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E’Eo-sTrM28/2B

5:6 Chrunfer.

5.6.1 All enteringendsof externallythreadedfastenersand threaded

cqenti _ have 45° Chamfecs(approxhately)frcunminor diametersorslightlyhelm mimr dianeters,unlessotherwi~ specified.

5.6.2 All enteringerdsof internallythreadedfaatenersand threadedcrspnents shall havenminal 900 -120° countersinksb or slightlygreater

than the threadnjor diaueters,unlessotherwi= specified.

5.7 ~lled threads.

5.7.1 C4xrple&lyforud threads.threadprofile,w~thi.nthe tolerance

(seefigure2.1).

5.7.2 InaaT!Pete formedthreads,

A carpletelyforned threadfollows the

znneover an axialdis=ce of cne pib=h

5.7.2.1 The lead-inthreadis measuredfran tk ed of the productto the

startof the firstcaupletet.hceadherethemjor dianeteris equal b theminimumati~e majordiaueterad the threadrcot is egua.1to the maxiunnnminordiauetir. This slrxddnot exceed2P (seefigure2.2).

5.7.2.2 The run-outthreadis neasuredbetweenthe transiticm@nt of theproductad the firstthreadrootwhich is anpletely formed,where th minordiaueterequalsthe ue.xinumermissibleminordiamter and the najordiam?terof the last fullyformedthread_ the minimumpenuissiblemajordianeter.When rcmtradiusis specified,1A? last cmpletely t%rmd rcotat tk minordieuetermustmet the reguireuent.See figure2.3 for full shankfastener,figure2.4 for pitchdiauetershankfastener,figure2.5 for shouldertolt,figure2.6 foroversizediametershankfastenerand figures2.7 and 2.8 Jim

threafledo hed fasteners.

6. Notes..—

6.1 ~~rsession note. In additionbJ supersedingFED-STD-H28/2Adated20 April198~~~~-&~nt alrn superseciesppendixXL of FED-SZD-H28dated

31 March1978.

7

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FED-S’I’&H28/2EJ

+-- r“.’ WI?,*D +

I I I r 6 BASICMAJOR m

—+— —

d UIN MAJOR DiA

— — — -62 B.UX PITCHCU

I

I II

‘d3MlN FOUNDEDROOT MJNDR VU

FIGURE 2.1 COMPLETELY FORMED EXTERNAL THREAO

w LEAD THREADS = 2P UAX

w

1

t= WD W SI+M

FIGURE 2.2 INCOMPLETE FORMEO EXTERNAL THREAOS, LEAD-IN THREADS

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F131-~H28/Z3

+---- MAX RUN””,2, ~ mMPL~ ~REMS —

FIGURE 2.3 INCOMPLETE FORMED THREADS, FULL SHANK

FASTENER -STANDARD DIAMFTER

F’=-;ETET”R-l—- —’

d M!N M4.JORDIA

f~”,~fi

FIGURE 2.4

+

INCOMPLETE FORMED THREADS, PITCH DIAMETER

SHANK FASTENER

9

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FECHTE-H28/?B

~MINRuNwT=lp+w.y

--

FIGURE 2.5 FULL SHANK FASTENER -STANDARD DIAMETER,

OPTIONAL CONFIGURATION (SHOULDER BOLT)

t-

MAX RUN0U7=2P+0VERS12EINCREMENT+ z TAWe MIN)

+

COMPLETE THREADS —

kmi wNw7. u=+WER -

y

SIZEINCREMENT + z Tb.N

12.~ 35.

!

-1/2 WERSIZEINCREMENT

NOTE:—- —

e =7RANs1710NTAPERNGLC

63 MAX WNDED ROOT MIMCf7ou

FIGURE 26 FULL SHANK FASTENER-OVERSIZE DIAMETER

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FElHmHu8/2s

E’::::,xT-—

— d UINMAJW WA

w—–

‘d, MAX RtMSCCD\~wJTuBK%lw—

A

FIGURE 2.7 FULL SHANK FASTENER -THREADED TO HEAD

W4DERHEA9 SURFA~

w UAX *2P +UAX FILLET RADfus mMFu_FE ‘mF(E4Ds —

MAX

~[z

1- W MINs0.6PFILLET + MAX FILLETRAlus RADIuS

-I_’l.-7“

‘+- TwU.D,A\

.~

I

d,MAX RIXJNSCD

L

ROJT MINCM91A

v

FIGURE 2.8 PITCH DIAMETER SHANK FASTENER -THREADED TO HEAD

1-l

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FED-STD+i28/2B

APPENOIXA

TAP DruLLsm AmiamMmKm SCKE SHS?,LIMI’ISEF?M?,i353WW

10. Smpe. ~is a-ix providessuggestedtap drillsizesand

recrmmkiedhcle sizelimits@iCable prior b firminginternalUnifiedscrewthreads. It is not a mandatorypartof tbe standard. The infonrati.m

containedhereinis intendedfor guidanceonly.

20. ‘hp drillsizes.

20.1 General. ‘Ibassurethat the mirmrd~ter of an internalthreadisheldwithinspecifiedlimits,it may be necessaryto use a reamerto finishthe

hole. A varie~ of factorsenters inb the productionof a clean,mud,straightlmleof tk currectdiameter. For a discussionof Mae ad other

data on drillingd @ping, referen~ my be made b “DrilledEoles forTapping”,a publicationof theUnitedStatesCuttinglbol 11’EtitUtd,

1230KeithBuilding,Cleveland,~ 441J.5.

20.2 !IabU2atedata.

20.2.1 Table 11.A.1givesminordiameterlimitsandcorrespdingpercentagesof threadfor s3.2staderd seriesthreadsup b @ i.nddiq 3.75inchdiameterfor classesI.Band Z. Teble 11.A.2 is a similartatd.eor class~. These tablesalso listsizesof drillsthat nay h expectedto drillholeswithinor nsar the specifiedminordiamter limits. Tlxsdiameterof the drill,theprobableInle size,ard the correepmiingpercentagesof thred are

tabulated

20.2.2 ~ a drillmay mxmal.lybe expectedto cut oversize,probabletdesizesare tabulatedthatare derivedfranprobablenmn oversi~s, &Mxilated. The followingis quotedfranthe ~tionad reprt: ‘...aseriesof testswas amducted by drillmanufacturers.Using six sizesofdrillsrangingfrrxn1/16” to 1“ in dianveter, totalof 2,808holeswere

drilledin cast ironad steel. Regularhigh speedsteeldrillsware usedwithdrilli.rqqui~t of the typenormallybud in metslmrking shops.... ~aver~e depthof kde drilledwas equalto 1-3/2 tinesthedril..liemeter.

&aeureurantof the lmlewas made at midpcintof the ds@ drilled....Theaverageof the...aumlntsoversize..shows a marked increasein arountwersizefordrillslargerthan 3/4”. For thissizerange reaming is recrmm&d. ”

12

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EZD-SDH28/2B

20.2.3 “Pe&eit of thretilistedin’tablei”is t& ratio“A P&& of theacti heightof tbred to & value O.75H;thisvalue is the basicthreadheightof the oblete AuericanNational‘l’’breadrofile. Since the basic

heightof a IlnifedThreadProfileie 0.625H,the maximampercent-iedpermissibleis 83.3%. Due to allnwmces ~r drillsto cut oversizeor due to

lackof availabilityof drills within~cified minordiametirlimits,tapdrillslistedin tables11.A.1d 11.A.2nBy sbw greaterthan 83.3%threads.This indicatesthatthedrill sizeis smallerthan theminixm.rnhreadminor

diameti arxladditional~hin~ of the hole my ha neoesearyin order topermit ecommlicaltapping.

30. ,Rermm’d d tde size limitsbeforethreadinq.

30.1 Genera+. Rx short lergthof engagement,the imleprior.to threadingslmti be heldnear the minimmnlimittoheightfor maximumjointstrength. AS lengthof engageurmt

diam?~ reouirednnximise th&adincreases,it is

advantageoustrJincreasetbe bok di.amterfor uoree&mcunical** withless riskof tap breakage.

Therefore,* followingreccammdaticasweredeveloped(alsosee 30.2 telow):

Lenqthof Engaq@m?nt

Upto

Atove

Abve

Atove

and incltiing 0.33D

0.33D thru 0.67D

0.67D thru1.S)

1.5D tkll 3.OD

Minimm Eble Size—.—.

M.iniumminor dia

Min m.imrdia plusl/4 minordia tiler-

ti.ini.mrdia plus

1,/2mina dia tilerance

Min mimr dia plus3/4 minor dia tolerance

MasinumEbleSize————

Mn minx dia plus3/2 minordie tilerarce

i+lininimdia plus3/4 minordia tolerance

Max minordia (reinirsx

dia plus tolerance)

Max mirmr dia plus l/4-r dia tolerance

(see30.2)

Fran the foregoingit will k seen that & differen~ betweenlimitsin each

range is the w and egud to halfof & minordiametertmlersome.This is a

generalrule. B’xever,the minimumdifferen~s for si~s below0.25in. are

equal b the minordiamtir tolerancesgiven in tables39 and 40 in ASMEB1.1-1989for lengtheof engagementto and includingO.33D. i%r lengthsof

engagementgreaterthanO.33D for sizes0.25 in. ad larger, the mininucn values

are adjusted sc thatthe differencebtween limits is never less than0.0040in.

13

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FED-STD-H28/2B

30.2 l’abulated= Recomnmded hole sizelimitsfor stadard LJnified

threads a~ scam?Speczal(UNS)threadsare given in tablesII.A.3ard II.A.4.For otherspecialthreads,calculatein acmrdan~ with 30.1almve;use mi.nii

minordiaueterad tolerancefran table3B of ASME B1.1-1989,or calculateinaaardanos-withsectian8 of ASME-Bl.q-1989ushg’Spprcpfate toleranoefran

table39 or 40 of lSKEB1.1-3.969fortoleran~ ratioof ‘1or frrmfirmlas b

Para9r@ 5.8.2of - B1.1-1989. Tabulatedholesizesad Imle sizescalculatedin accordancewith 30.1 are not mrdatory unlessthe threaddesignationstatesthendified minordiarreterimitsard & designationMXl

in accordancewith paragraph6.7 in ~ B1.1-3989. If mdified minor diametelimitsare not specfied,acceptancewillbe in acrmdance with stardardminordiameterlimits.

Ncn!E:~ed maxinnnnole sizesin 30.1, for lengthsof engagsrmkgreatertha 1.SD are outsidestarxiardinordianeterlimits. They are notincltisdin tables11.A.3and 11.A.4. Use of a minordiamter hrger thanstandardwill resultin a reductionin sheararea of the externalthreadsofthematingpart. If manufacturingprocesspermits,maxinznnhole size before

threadingskuld ke maintainedat the higheti of the stardardmi.mr diameterlimits.

30.3 Otherccmsiderations.When tappingrelativelysoftmaterials,

especia~--f i.nepibch threads,thereis a terdencyfir the materialto besqueezeddown towardsthe rrmtof the tap so thatthe minor diameterof thetappedholeuay.berxwremallerthan thediameterof thedrilledtnle. It may

be necessaryto try a differentsizedrillor differentstyle tap to assureasatisfactorythread. ..

7/14/2019 FED-STD-H28-2B


.

j

m

—-—_—. ... . . ..-- __ —____ . . . . -

15

7/14/2019 FED-STD-H28-2B


FED-STD-H28/2B

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I

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16

7/14/2019 FED-STD-H28-2B


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17

7/14/2019 FED-STD-H28-2B


FEESTD-H28/2B

18

7/14/2019 FED-STD-H28-2B


E%&SlEH28/23

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—

—

—

7/14/2019 FED-STD-H28-2B


FED-Sl’’D-E.28/Z0

.+

—

—

—

—

J —

—

- —, —

1

20

7/14/2019 FED-STD-H28-2B


Fm-s’llH128/2B

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4. +- . . . . - . . . . . . . . . . . #-l . . ..-..- ++ 4 . . . . - . . . . .—— = - ~- ++—

21

7/14/2019 FED-STD-H28-2B


FED-STIH128/2B

I

—

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-.4..-. 4.+ . +- . A 4+- . - ! ” . . ++- . . . .. . . . . 4+ -. m

~w%=— +-

22

7/14/2019 FED-STD-H28-2B


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23

7/14/2019 FED-STD-H28-2B


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7/14/2019 FED-STD-H28-2B


FED-srD-H2f3/2B

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—

7/14/2019 FED-STD-H28-2B


FED-srBH28/2B

26

7/14/2019 FED-STD-H28-2B


EIZ)-SIQ-H28/2H

ii

7/14/2019 FED-STD-H28-2B


l?ED-sTIHG!8/Z3

28

7/14/2019 FED-STD-H28-2B


F12?-.SlQ-H28/2B

N

0+L- 1n

ii

.j

5-15Wl2°3

I ~ I i

I I

i II 1‘I I II

29

7/14/2019 FED-STD-H28-2B


FEW5TD-H28/2E

—

—

m111

ii

30

7/14/2019 FED-STD-H28-2B


F311-STD-H28/ZB

31

7/14/2019 FED-STD-H28-2B


Fl?QSTD-H28/213

i I

I ‘I’11

I Is

s

32

7/14/2019 FED-STD-H28-2B


.

5

S’i mm

---

EED-ST13-E28/Z3

33

7/14/2019 FED-STD-H28-2B


EED-S’IT2-H28/2B

‘2nsLs11.A.3- ~ ~le size lim2fs tefore threading for different lergt.hsof e!qaqsrr?nt,stm3ard

Unifid ad saa? UtG threads, c3ds.se6IB and 272(see 30.1) IJ

Sm.iml size in fncb22

ard thteds &Er kc!)

1

.06C+0 or M. 0-44

.07344 or M2. l-a

.073-72or h. 1-72

.08+56 or f&. %56

.006-64or N2. ‘WJ4

.099-48or m. 2-48

.099-36or M. 3-56

.112-40or m. 4-40

.U-48 or !b. 4-48

.125-40or 242.5-40

.n5-44 0s m. 5-44

.232-32or w.. 6-32

.13s40 01 m. 5-40

.16+32 or NO. 6-32

.164-36or WA 8-36

.190-24or lb 10-24

.290-32or 243.lC-32

.216-24or lb. 2.2-24

.21620 or m. 12-28

.216-32or M. 12-32

.250-20or 3/4-20

.250-22or 2/4-20

.250-32or L/4-32

.250-36or 3/4-36

.50C-22or 3/3-12

.500-13or 2/2-13

.500-16or W-16

.50C+20or 3/*Z

.500-38or 3/3-2E

.50C+32or U2-32

See fmt730tesat e

Series

designatim

2

Ow

mcUfw

ox

LaF

LxUNF

OKw

mc

13mLmP

Uw

Luc

2am

w2WNCKm

w

w2Cm

Cm

2m

UMT

ma

ox16U4

w

32m

of table.

minx di=ter of internaltieais

3

~

0.0465

.0561

.Osao

.0667

.0691

.0764

.0797

.0049

.oa94

.0979

.1004

.104

.22.3

.130

.234

.145

.356

.171

.177

.182

.196

.211

.216

.220

.252

.256

.267

.274

.279

.282

.307

.322

.330

.336

.341

.345

.360

.370

.303

.399

.404

.410

.417

.432

.446

.461

.466

Percmd

of

tied

4

83.1

83.3

83.1

83.2

83.3

83.5

03.2

83.4

83.5

M83.8

83.1

a3.i3

83.1

83.1

83.8

83.124.1

83.8

83.1

84.183.0

83.1

83.8

83.9

64.183.0a2.5

84.5

63.8

a3.1

63.184.1

a3.B

83.1

83.583.1

a3.983.0

82.5

83.1

E3.1

83.6

83.104.1

83.8

5

in

0.0514

.0623

.0635

.0737

.0753

.oa45

.0865

.0939

.0968

.1062

.1079

.324

.2.39

.139

.142

.2.36

.164

.3al

.106

.140

.207

.220

.224

.226

.265

.270

.277

.222

.2s6

.ZS9

.322

.332

.340

.345

.349

.352

.376

.3a4

.395

.407

.411

.42a

.434

.446

.457

.470

.474

PmmYof

nueed

6

53.0

S?.7

32.7

53.0

52.7

52.653.9

55.7

56.2

59.1

58.5

61.6

a.o

62.864.0

64.764.7

64.0’

66.2

64.7

R

65.B

65.4

65.665.7

65.365.1

66.566.2

64.764.7

64.0

63.7

66.365.9

65.465.7

65.3

66.5

66.0

66.5

66.2

H

34

7/14/2019 FED-STD-H28-2B


Htntlmml

0.&65

.0563

.0560

.0667

.0691

..0764.0797

.0849

.0894

.0479

.1004

.104

.332

.230

.134

.145

.156

.m

.u7

.M2

.296

.22.3

.216

.2’M

.252

.254.

.167

.274

.279

.202

.307

.322

.330

.336

.342

.345

.360

.370

.383

.399

.404

.410

.U7

.432

.446

.4Q

.466

mxifm

B

2n

0.0500

.0599

.062.3

.0705

.0724

.0604

.0831

.oa49

.0931

.1020

.Lou

.109

.235

.135

.228

.250

.160

.176

.182

.3B6

.202

.216

.220

.223

.259

.264

.272

.276

.262

.286

.314

.327

.335

.340

.345

.348

.368

.377

.389

.403

.407

.429

.425

.422

.452

.466

.470

limitsfor diftesent;

AtlYM 0.330 &“ o.6m

UlnImm

9

0.;79

.0560

.696

.0626

.0707

.0785

.0014

.0871

.0912

.1000

.1023

.106

.223

.132

.136

.147

.E8

.m

.179

.264

.B9

.233

:%

.256

.261

.27o

.276

.220

.203

.323

.326

.332

.338

.343

.346

.364

.373

.386

.403

.405

.414

.421

.436

.449

.463

,468

10

in

0.0514

.062.6

.0624

.0724

.0740

.0225

.0848

.0916

.0949

.1043

.1060

.2.22

.U7

.137

.140

.253

.162

.178

.184

.288

.204 .(

.222

.222

.225

.262

.267

.275

.260

.284

.287

.318

.330

.337

.343

.347

.350

.372

.320

.392

.405

.409

.423

.430

.443

.454

.468

.412

* of ~t

M0m3 0.670 thru 1.53!

in0.0479

.0565

.0602

.0699

.0720

.0205

.0831

.0894

.0931

.1023

.1042

.lm

.3.25

.2.34

.228

.150

.160

.176

.221

.2.66

.202

.216

.220

.222

.259

.264

.272

.278

.2a2

.205

.314

.327

.335

.340

.345

.348

.360

.377

.389

.403

.407

.43!4

.425

.439

.452

.466

.470

mximxa32

In

0.0514

.0622

.0635

.0737

.0753

.0045

.0865

.0929

.0%8

.1062

.lm9

.114

.129

.139

.142

.2s6

.164

.181

.266

.25’0

.207

.220

.224

.226

.265

.270

.277

.262

.266

.=9

.323

.332

.340

.345

.349

.352

.376

.384

.395

.407

.433

.422

.434

.446

.457

.470

.474

!4dna3 s!= in *

adt.hreadsperird

1

.060%0as m. M30

.m~~ m. I-64

.07>72 or lb. 1-72

.086-56K b. 2-56

.086+4orb. ‘N4

.03+48 or b. 3-48

.099-56orlb. ?-%

.2M-40 or m. 4-40

.3X4-48or m. 4-48

.125-40or m. HO

.32s-44or m. 5-44

.138-32or m. 6-32

.238-40or m. 6-40

.164-32or lb. +32

.164-36ox b. 6-36

.390-24Or b. lb24

.39C-32or h. 10-32

.216-24or h 12-24

.236-20OZ m. P26

.236-32or m. 12-32

.350-m or 3/4-20

.230-200s 2/4-20

.25*32 or 3/4-32

.250-26or 2/4-36

3125-1Sor 5/36-32

3125-20or 5f16-2c

3125-24or 5W24

3125-26or 5/16-26

32Z5-32or 5/36-32

3125-36or V26-24

.375-16or 3/S16

.37>20 or 3/8-20

.37>24 Or 3/6-24

.375-20or 3/2-22

.37532 or 3/S32

.375-36or 3/S36

8375-140[ 7/3.6-14

1375-16or 7/36-16

wrf-m or 7/26-20137s-22or 7/36-22

137>32 m 7/M-32

50c-12or 2/2-12

.50C-13or 3/2-13,500-16or 3/>16

.Soo-m or 3/2-20

.500-22or 3/2-28

.50C-32m 2/2-32

See fcotnotesat end of table.

35

!1

7/14/2019 FED-STD-H28-2B


~STEH28/2B

‘B&E 11A.+= kamx%x3ed txzhzsize limits tefore threadiq for diffezent krqths of engiqemnt, sbrdardUnified u-d safe UNS thzea&, chsses D and 2S (see 30.11 IJ - untinkd

Nminalsize in inches

Fm5threads per inch

.5625-12 or 9/26-32

.5625-16 or 9/26-16

.5625-18 or 9/36-18

.5625-20 or 9/16-20

.562524 or 9/16-24

.5625+20 or 9/16-28

.5625-32 or 9/16-32

.625-u or 5/8-11

.625-12or 5/8-12

.625-16r 5/8-16

.625-3.8at 5/8-18

.625-20 or 5/8-20

.625-24 Or 5/8-24

.625-28 or 5/8-28

.6&32 or 5/8-32

.6875-12r

.6875-16or

.6875-18 or

.687+20 or

.687+24 Or

.687528 or

.6875-32or

.75C-1001 3/4-10

.750-12 or 3/4-12.750-16 or 3/4-16

.750-18 or 3/4-18

.750-20 or 3/4-20

.750-28 or 3/4-28

.750-32 m 3/4-32

.875-9 C: 7/8-9

.875-12or 7/8-12

.875-14 Or 7/0-14

.875-16 or 7/8-16

.P75-18 or 7/8-18

.875-20 or 7/B-20

.87S28 or 7/8-28

.875-32 os 7/8-32

.9375-12r 15/16-12

.937516or 15/16-16

.937>20 or 15/16-20

.9375-28 or 15/16-28

.937532 or 15/16-32

* fmtnotes at end

Series

designatim

Inc

mm

w

cmc3-

2mN3am

w2.3U?

16UNl.uw20026m2mN33U4

12UNlamm20UNK322F285S3mN

m

127JNw?mw26UN3mN

3mN12UNus

..oNir2m3ZM

Luc12UNwMmmm261m

32m

12L2+lamm2mN32UN

ale .

3

in.412

.495

.502

.508

.517

.524

.529

.527

.535

.557

.565

.571

.580

.566

.591

.597

.620

.627

.633

.642

.649

.654

.642

.660

.682

.690

.6%

.713

.716

.722

.745

.752

.75a

.774

.779

.755

.785

.758

.807

.815

.821

.836

.841

.847

.S70

.803

.e99

.?,]4

Fer03mY

of

lhread

4

83.683.183.8e3.984.1e3.o82.5

83.083.1

83.083.183.183.184.183.8

83.6e3.183.883.984.1e3.o82.5

B3.1

83.183.883.1e3.184.183.B

83.6e3.183.8a3.983.0e2.5

e3.183.1e3.o93.883.1e3.184.1e3.8

e3.6e3.183.9e3.o82.5

.

2/Uaxiirmn

.4mw

.509

.525

.520

.527

.532

.536

.546

.553

.571

.578

.582

.590

.595

.599

.615

.634

.640

.645

.652

.657

.661

.663

.670

.6%

.703

.707

.7m

.724

.740

.759

.765

.770

.7e2

.786.,

.778

.803

.814

.ezl

.828

.832

.845

.849

.865

.884

.e95

.907

.911

Percent.Yof

l?uead

6

67.o

65.9

65.8

65.4

65.6

65.7

65.3

66.966.5

66.565.166.264.764.764.0

67.0

65.9

65.8

65.4

5.6

65.7

65.3

67.0

66.566.5

65.1

66.2

64.7

M.o

67.o

65.9

65.865.465.7 ‘65.3

67.266.565.766.565.166.?fd.164.0

67.0

65.9

65.465.765.3

36

7/14/2019 FED-STD-H28-2B


-s273-H28/2B

?S+?JZ1.A.3-- &mmenkd ble size lfmfts bebre thrediq for different lengths of erqqanent, sbdard---

. .= Unified ad m IRS threaas, d855es D and 2S (see 30.1)1/ - mxmina=. .

Reccmrer&d Ikzk size limits &r different h

Minilrm

7

in

.472

.495

.502

.508

.517

.524

.529

.527

.535

.557.565

.571

.580

.5s6

.591

.591

.620

.627

.633

.642

.649

.654

.642

.660.682

.690

.696

.731

.116

.722

.745

.752

.7’58

.774

.179

.755

.785

.798

.807

.835

.821

.836

.842

.847

.870

.883

.899

.904

-

14axflmm

8

.a

.502

.509

.514

.522

.53s

.532

.536

.544

.564.571

.5n

.5s5

.590

.595

.606

.627.

.634

.639

.647

.653

.657

.652

.6697.689

.6%

.702

.716

.720

.731

.752

.759

.764

.778

.702

.766

.794

.806.814

.823

.827

.840

.845

.856

.8n

.889

.903

.907

Abw 0.330till 0.67D

Hir.imm

9

in

.4n

.498

.506

.531

.520

.526

.530

.532

.539

.562

.568

.574

.582

.5s8

.593

.6o2

.623

.630

.636

.645

.651

.655

.647

.664

.686

.693

.699

.7D

.72s

.727

.748

.756

.761

.n6

.780

.760

.789

.802

.ul

.810

.824

.838

.843

.852

.873

.BB6

.901

.905

Ma%h.m

10

fn

.486

.505

.532

.517

.525

.530

.534

.541

.54B

.56S

.574

.5$0

.587

.593

.597

.62.3

.630

.637

.642

.650

.655

.659

.658

.673

.693

.699

.704

.72s

.722

.736

.755

.762

.767

.7s0

.7s4

.772

.79B

.B1O

.83,s

.824

.B30

.843

.B47

.861

.BSO

.S92

.905

.909

Ith of mgag.3Tent

AkNe o.6m till1.5D

u

in

.4s2

.502

.509

.514

.522

.526

.532

.536

.544

.564

.571

.sn

.5B5

.590

.595

.606

.627

.634

.639

.647

.653

.657

.652

.669

.6B9

.696

.702

.716

.721

.731

.752

.759

.764

.778

.782

.766

.794

.806

.B14

.B21

.827

.840

.845

.856

.877

.BB9

.903

.907

3.2

in

.490

.509

.53.5

.520

.527

.532

.536

.546

.553

.571

.57B

.502

.590

.595

.599

.61.5

.634

.640

.645

.652

.657

.663

.663

.676

.696

.703

.707

.720

.724

.746

.795

.765

.770

.782

.786

.778

.B03

.B14

.821

.828

.832

.845

.849

.865

.884

.095

.907

.911

tbina.1size fn inches

ard thre&2s per inch

1

.5625-2.2r 9/26-22

.5625-16r 9/26-16 “

.5625-2Br 9/26-18

.562E-2or 9/1+20

.562524or 9/M-24

.5625-26r 9/!lG2B

.5625-32m 9/16-32

.625-3.3or 5/B-31

.625-3.2r 5/6-12

.625-16 or 5/S-16

.625-18OK 5/S-lB

.625-20or 5/s-20

.625-24or 5/0-24

.625-2B or5/0-23

.625-32015/S-32

.750-10or 3/4-10

.750-12m 3/4-12

.750-16or 3/4-16

.750-2.sr 3/4-18

.750-20or 3/4-20

.750-2Sr 3/4-26

.750-32or 3/4-32

.B125-12or13/16-12

.6225-16or 13/16-16

.52.25-2.6r 13/26-3.8

.B3Z5-20r 13/26-20

.s325-2s or 1016-2B

.B2Z5-32 or 13/16-32

.87+9 0.?7/8-9

.87>12 or i’/B-l2

.B75-14 or 7/B-14

.875-16 os 7/8-16

.875-18 or 7/B-18

.875-20 or 7/s-20

.875-28 or 7/8-28

.87~32 OS 7/8-32

.937512m 3.5/16-12

.9375-16r 3.5/16-16

.9375-200235)26-20

.9375-26m 2s/26-20

.937532or 25/16-32

Ses fcotiotesat end of table.’37

7/14/2019 FED-STD-H28-2B


i?EESTD-H28/2H

[email protected] ~ bk SiZ limitsbb:e threading br different lerqths of qpt, s-d

3222ifie3a7933x9th2’ea, ~ ls30Ya2E (see30.l)y-mtti.. -., ..-.

.._- _>. ..

W.run&

1

1.000-81.WC-U

1.ML=141.-161.*231.-291.000-261.WO-22

1.12S-71.22581.125-221.223-161.125-2s1.123-20l.mia

1.267581.ls75121.387S-161.2237+.01.1675-201.2B7>i$

1.332561.3125-121.317S-16!..U5-181.3125-201.3223-in

1.3-1.375-61.37+131.375161.37+181.375a1.375-28

1.4315-6L.4375-81.h375-221.437+161.437>191.437+201.4375-20

1.5U-6l.sowe1.300-121.500-161.500-101.500-301.500-28

mlZM

14221wmm

2mnl

wlM

Emol2a31

wmlm

if%

am

mlam161.31w2culZmm

mmma

s2M342mm

Q.Nm+1224

=

2m14

lmc6m13w

Ll&$201J426W

3

.86S

.92a

.922

.932

.940

.966

.961

.966

.927

.972

.985

.9951.0021.0091.024

0.970.990

1.0231.0571.0651.0711.096

1.0s21.0973.2201.1271.2331.149

LR1.1601.182

1.1901.1%1.232

1.1771.2221.2451.2521.2691.114

1.1951.2401.2831.3L771.32.51.37.21.334

dkza o

P&ma

&

4

83.183.163.083.083.183.184.183.8

03.4.83.683.583.183.883.983.0

83.s83.183.182.983.183.184.1

B3.483.683.183.883.983.0

83.583.183.183.6

83.183.184.1

83.483.683.183.803.903.0

82.183.183.183.083.183.184.1

E3.483.483.683.183.883.983.0

83.183.383.1a3.a83.183.164.1

5

.890

.93s

.92a

.946

.952

.957

.970

.974

.952

.9301.OCII1.0091.0231.0201.032

0.99B1.0351.0521.0711.0781.C821.095

1.077 ‘l.lls1.1241.1401.145l.m

1.2221.1401.1701.1%

1.2031.2m1.220

1.2021.2401.2591.2651.2701.282

3.2231.2651.3031.32)1.3281.3331.343

1.Z81.3271.3651.3841.3901.3951.407

1.3S01.3901.4’231.4661.4531.4571.470

.%;66.365.965.865.465.7

68.467.766.5

6?:66.264.7-

68.167.065.965.865.465.7

60.4’67.766.566.s

65.166.2.44.1

68.167.065.965.065.465.7

69.367.766.566.565.166.264.7

69.1

68.167.065.965.065.465.7

69.367.764.566.565.166.244.1

See fczhotes at end of tihle.38

7/14/2019 FED-STD-H28-2B


- 11.A.3- Rxxxmended ble size lSmits kfore threadfng for difEerent leqtb of erq6g@m?nt, stamkxd

Unified ti sme UKi threti, classes 3B and = (.93.30.1) 3J - .xzztimzd

‘~ b2s aim lkks fordiftermt kq?im of ~t.

m ad inchdiq (1.3D

14inlmn

.865

..910.923.932.940.946.962.944

.927

.972

.903

.9931.002l.om1.024

0.970

.9901.03s1.0371.0651.0721.066

1.0321.0971.1201.2271.3311.149

1.0951.2.251.3401,,+221.290

1.1961.231

1.1771.2221.245

J.2521.2581.274

1.1951.240l.im1.3071.3351.3231.336

1.257

1.3021,3471.3701.3771.3031.399

1.3ZI1.3651.4101.432

1.4401.4461.461

Seef

Kaxim3a

8

.877

.939

.932

.939

.946

.9S2

.9+6

.9m

.940

.901

.9931.0021.0091.014

1.02a

0.984

1.0021.0441.CU1.0711.077

L090

1.261.1061.2271.U41.2391.M3

1.1091.1271.1691.1091.296

1.2021.22.6

1.199

1.2331.2521.2591.2641.275

1.2301.2s21.2W1.3141.3321.3271.340

1.272

1.32s1.3561.377

1.3841.3891.403

1.3351.3771.4291.439

1.4461.4521.666

notes

Mvvc 0.3m thru0.67D

.871

.914

.927

.936

.943

.9i9

.%3

.94a

.926

.9n

.909

.9981.W61.0231.026

0.977

1:%1.0411.0661.0741.0s8

1.0$91.1021.2231.2301.1361.231

1.3021.ul1.164L 2661.293

1.1991.223

1.1841.2271.24S1.236

1.2611.276

1.m21.2461.’209L3231.3301.3241.338

1.265

1.3oa1.3521.373

1.2601.3861.401

1.3271.3711.4141.426

1.4431.4491.463

end of

6baimm

M

.804

.923

.934

.943

.949

.954

.96E

.972

.946

.9S6

.?971.m31.0321.017

1.OXI

0.991

1.00B1.0481.0661.074l.ozn1.093

1.071

tE1.1371.1421.355

1.1161.3341.1731.3931.199

2.2041.220

1.L961.2%L2351.362

1.2671.200

1.2291.2301.29s1.3261.3241.33S1.343

1.-280

1.3211.361l.zao1.3871.392L.405

1.3431.3S41.4221.443

1.4491.4561.466

P&W 0.6792tuul.m

~b

u

.8n

.929

.931

.939

.946

.9S2

.%6

.970

.940

.981

.993

1.M21.0041.0141.028

0.964

1.0021.0441.0641.0711.0771.090

1.0651.2061.1271.1341.1391.233

1.1091.1271.1691.1891.296

1.m21.216

1.2901.2311.2521.2391.2641.278

1.2201.2521.2941.3141.3211.3271.340

1.272

1.3231.3561.377

1.3841.3891.403

1.3351.3771.4291.4391.4461.4521.466

able.39

12

.890

.929

.92a

.944

.9s3

.957

.9m

.974

.962

.990

1.0031.0091.0231.0201.032

0.996

1.0351.0531.0711.0761.0221.09s

1.077

::s1.1401.1451.357

1.3231.1401.1-681.3961.203

1.2071.2m

1.m2

1.2401.2591.265

1.2701.2E2

1.2251.2651.3031.3211.3.291.3321.365

1.288

1.3271.3651.384

1.3901.3951.407

1.3301.3901.4201.446

1.4s31.4571.470

F3%D-STD-H28/2B

1

1.000-s1.000-121.00C-141.000-26L.mu1.O*2Ol.oocl-z

1.029-32

1.0625-4

1.0625-321.06zr141.0625-161.06S361.oa5-iQ1.0625-26

1.12.5+9

1.250-71.250-61.250-121.25*161.2s2-20

1.2s0-201.25C-2E

1.375-41.37S-81.37s-121.275-361.375-381.27s-m1.27S-2E

1.4275-6

1.4375-61.4375-121.4375-16

1.4s73-281.4375-2U1.4m528

1.50C-61.500-81.300-121.500-16

1.500-lB1.5oo-m1.500-26

7/14/2019 FED-STD-H28-2B


- IIA.3- ~ tie sizeliaitssfnrethrediqh differentxqthsof~:, s.-

Mif+edald 6uIlew4hreadS, c38sses 231am53s(see30.1)J-amtinw2.m

Nmina2iai zefnfnctrsal’dthreadsperincb

1

1.5625-61.5625-81.5625-221.5625-161.5625-3S1.5625-20

1.625-61.625-8

1.625-321.625-16

1.625-M1.62S-20

1.6875-61.687>81.6s75-121.6S75-161.6s75-3s1.6675-20

1.750-51.75f+61.750-81.750-121.75C-161.750-20

1.62.25-61.U25-8l:ux-lz1.8125-16

1.822s-20

1.87S-61.87581.875121.875161.875-20

1.9375-61.9375-81.9373-U1.9375161.9375-20

2.000-4.52.000-62.000-82.000-12

2.000-162.OW-20

WIes

designatim

2

m?m

lzwm2t4m

SJNm

1224Mmmm2om4

mN

liutl1s2!4-20UN

mmSLm

lam

mn4

64E4mmmMm

2om

tm4mDmla20UN

6m4WNMN161n420UN

m

60N8ot4

H

Mm? diam?teto]

3

M

1.3821.4271.4721.4951.s021.s08

1.4451.490

1..s351.5571.5651.571

1.5071.5521.s971.620”1.6271.633

1.5341.5701.633

1.6601.6821.696

1.6321.6771.7221.7451.759

1.6951.7401.7851.807l.szl

1.757l.aoz1.8471.8701.883

1.759Lam1.8651.910

1.9321.946

4

83.483.483.683.183.sS3.9

83.183.1

83.183.883.163.1

83.4S3.483.683.183.8S3.9

83.1

E::

83.183.8

83.1

83.483.483.683.183.9

S3.183.1

w83.1

83.4S3.483.683.183.9

83.583.183.1S3.1

83.883.1.

,terraltb

2/Haxim.m

5

fn

“1.423

1.4521.4901.5091.52s1.520

1.47s1.52.s

1.5531.5711.5781.5S2

1.53s1.5n

1.6351.6341.6401.64s

1.56s1.6001.640

1.6781.6961.707

1.663

1.7021.7401.7591.7m

1.72s1.7651.s031.8211.832

1.7881.8271.8651.8841.895

1.7951.8501.BSO1.92s1.9461.9s7

s

I%m2el#of

‘nueFd

6

69.166.1

67.065.965.865.4

69.367.7

66.566.565.166.2

69.1

67:;65.965.865.4

70.169.367.7

66.566.5

66.2

69.16s.167.065.965.4

69.3

67.766.566.566.2

69.168.1 ,67.065.965.4

* fmtnotes at end of tible.40

7/14/2019 FED-STD-H28-2B


3’Ec-s213-E28/213msl.z11.A.3- ~ Imle size limits &tire threading for different leqths of eqeqenent, st.add

Lh-llfied-- LW threads, c2a59e9 2s and m (see 30.1) y - atillu33

----P f bok eim Mmitsztirdifferentlength of engagent...s

2b &d incluihg o.33n

1.3821.427

1.4721.49s1.s02

1.s09

1.4451.4901.535l.sn

1.5651.571

1.5071.S521.5971.6201.6271.633

1.5341.5701.6U1.6601.602

1.696

1.632

1.6771.7221.7451.758

1.69S1.740I.78s1.807l.ml

1.757

1.8021.8471.870

1.883

1.7591.S2U1.86s1.910

1.932

1.946

1.3971.440

L 4811.s02

1.5091.s14

1.460

1.5021.5441.564

1.5711.577

1.5221.S65

1.6061.6271.6341.639

1.S501.ss51.6271.6691.6s9

1.702

1.647

1.6901.7311.752

1.764

1.7101.7521.7941.814

1.827

1.n21.s351.E561.877

1.8s9

1.7771.8351.8771.919

I 1.939

1.952

1

Atove 0.330thru 0.67D

in

1.3901.434

1. 4n1.4981. S061.531

1. 4s2

1.4%1.5391.s61

l.sa1.574

3.5351.558L 6021.6231.6301.636

1.s42~.sn1.6211.6641.686

1.699

1.6401.6841.7271.7481.761

1.7021.7461.7891.8221.824

L 765

l.wa1.8s21.873

1.s.86

1.7681.8271.8711.9141.936

1.949

in

1.40s1.446

1.4861.s051.53.2

1.517

1.4601.5081.S481.563

1.5741.ss0

1.530

1.5711.6311.6301.637

1.642

1.S591.s93.1.6341.6731.693

1.704

1.6551.6961.7361.7551.767

1.72E1.7501.79B1.8181.830

1.7801.8211.861

1.B801.892

1.7861.0431.B841.9231.943

1.954

AtUW 0.67Dthnl1.5D

IF4inimun

2.3

in

1.3971.440L 4011.502

1.s091.514

1.4601.s021.s441.s64

1.5711.577

1;5221.56S1.606

1.6?)1.6341.639

1.5s01.5s51.6271.6691.689

1.702

1.6471.6901.7311.7521.764

1.710L7521.794“1.814

1.827

1.7721.8351.8561.8n1.8s9

1.777

1.8351.8771.929

1.9391.952

22

.fn

1.4231.452

1.4901.509

1.5251.520

1.475

1.5251.5531.571

1.578l.saz

1.s38

I.sn1.6251.6341.640

1.645

::%1.6401.6781.696

1.707

1.663

1.7021.7401.7591.770

1.72s1.7651.8031.WU1.832

1.7881.8271.8651.8841.s95

1.795

1.8s01.8901.928

1.9461.9s7

Nminel size in inche

Flt-f3thmadsprincb

1

1.S625-61. S625-81. S625-221.s625-161. S625-181.562S-20

1.625-61.625-B1.625-121.62+16

1.62S-181.62S-20

1.687Fr61.687S-81.6875121.6875-161.6875-181.607s-20

1.750-51.7s&61.750-8Z.750-121.750-16

1.750-20

1.812s-61.RU5-S1.8125-221.0U5-161.8125-20

1.87M1.875-81.875-121.87S-161.87520

1.9375-61.9375-81.9375-121.9375161.937>20

2.00C-4.52.000-62.000-82.00C+12

2.000-162.000-20

See faJtnotesat em3 of table.41

7/14/2019 FED-STD-H28-2B


Ew-s’Iwz28/a

.=,

2%BtZ 11.i3 ;-.~q

mle size MmLts bebce thswding for different lerqths of eq&&nt, star&JK

Unified and mre W thretds, C- f.fld m (sse 30.1) ~ . -&*

~simininches

?lrdthre.adsperirch

2.062!+16

2.125+2.U+62.225-122.3.25-162.225-20

2.3E75-16

2.250-4.s

2.250-6

2.5C4)-42.%3.000-43.250-4

kMi

sxies

desigmatim Mi.nimm

=lF3

in

1.995

ml 1.945mm 1.990

2.03516U4 2.057XKR4 2.071

lx 2.la3

w 2.009Sam 2.om

Um 2.229WC 2.479m 2.729

2.979

See botmtes at E-X3of table.

42

4

83.1

83.1

83.183.183.883.1

83.1

83.583.1

:::83.483.4

5

in

2.0U3

1.9752.02s2.o532.0712.082

2.334

2.0452.100

2.2672.5172.7673.017

Ikmentv

&6

65.9

69.367.766.566.566.2

65.9

71.069.3

71.771.771.771.7

7/14/2019 FED-STD-H28-2B


FE23-STD-I?28/2B

~ bale siza 3.fmiteti different L

m ard fm2h251ng0.330IIAbve 0.3m thfu 0.67D

6uldms0

7

in

1.995

1.945.1.9902.0352.0372.072

2.320

2.009

2.070

2.22s2.4792.?392.979

%

M82icd0nfniam

8 9

in fn

2.002 1.998

1.960 1.9522.002 1.9962.044 .2.0392.064 2.0612.077 2.074

2.227 2.322

2.027 2.03.82.065 2.077

2.240 2.239.2.498 2.4a92.748 2.7392.998 2.989

Mlxilmm

10

in

2.005

1.96E2.0082.0482.0602.060

2.230

2.0362.093

2.254‘-

2.508

2.756

3.008

Nfnf2mn

2-3

in

2.002

1.%02.0022.0442.0642.077

2.127

2.027

2.085

2.2402.4982.7462.998

23

h

2.009

1.9752.0252.0532.071Z.C&?

2.334

2.04s2.100

2.202.5172.7673.017

.-. . ––—

!kmfnalaizef.nti

Ludthretdspximll

1

2.0625-16

2.3.25-42.=82.125-122.323-16’2.12?+

2.3S7%16

2.250-4.s2.250-6

2.300-42.750-43.oco-43.=0-4

~ ~~yg be.- limits.e qud m tb Anc.r dimcu~ tdermxs Liu3mgth90f

Ibever, * minikam v83ues -r lengths of=Jw==t-~

aqagewmt gredter than 0.33nin Sims 0.25 i

and hrgez &e &!smd w that th! difference &been lfmfm Is _ less b 0.0040 h. ror dimce--

piti &inaticzm ot.br tbm tlcee given in this mk.2e, am 30.2.

Zble nize limits &a dimcet.ec-piti ccmbfnatims which * -t ~ fn this W my k *-- M M Of

dun in this @da prcdded them is a diareter~imh ux&dnatim fn ths tabki

(1) b-itht6=cuImpimbm3(2) with~ dtik thatislessty m fntegm2tmnmt &m tb dfmrebr+ti carhna tfm fm which ka3e si

vabm aze &sized, 0211S:Values In * table fur mninn3 sizes 2ess ttmn 0.25 in. c9m0t be used far

this pq2192. )

E2P2KlW lb cbtain * values for * 4.0*S2E or = thread, ad 2.000 b n2WS &r * 2.000-5N

Uueadslxamh t!mtahle. ‘17)esaalue.quuld thm ~: 3.865, 3.877, 3.871, 3.B84, 3.877,

3.890. m PCrmlas of thread Wu.2 Zemfn Imchmlpea.

2J B.mA cm .Ue2. . randed off in tke prhirq .lum. 100 perumt of threzd - 0.791 [see 30.2.3).

lJ0asedonak@hofwwtqa3 tntlt?mmdrtal ditureter.

43

7/14/2019 FED-STD-H28-2B


FED-ST13-H28/29

7mmE 11.?+.4 ~EX7 Imlesizelimitsbeforethreadiq h differentkqtb of mgagment, st.ar

Onifiedd s=e W tbreds, * 3B [see30.1)~

“a

9

?linordiambx of inte~ ~e

Y

1

.060-8001lb. 0-80

.073-64 or N2. 1-64

.073-72or t b . 1-72

.086-56or No. 2-56

.086-64or No . 2 -6 4

.099-48or M. 348

.099-56or lb. 3-56

.122-40or b 4-40

.3X+48 or M. 4-48

.125-40or m. 5-40

.12544 or W. 544

.13S-32or b. 6-32

.138-40or No. 6-40

.164-32or M. %32

.164-36 or W. 8-36

.2.90-24r No. 10-24

.290-32or N& 10-32

.216-24or M. 1%24

.216-28 or NU. 12-2a

.216-32 or M. 12-32

.25C-20

.250-28

.250-32

.25C-36

.3125-M

.3125-20

.312524

.3125-28

.312>32

.3125-36

.375-16

.37>20

.375-24

.375-28

.375-32

.375-36

.4375-14

.437>16

.4375-20

*r ies

Iesignatim

.431!+28

.4373-32

* fwb-des at d of t ah 3e .

trw

Lrc

OK

m

IRK

m?

UK

Um

m02-F

w

Lw

UNF

w

W

Low

m

UK

InfF

OtEf

w

o-m2UIN

2671Nmm

‘K20UN

UNF2euNIilJmm

m16UN

m

327RJ

3

in0.0465

.0561

.0580

.0667

.0691

.0764

.0797

.0849

.0894

.0979

.1004

.1040

.Ulo

.3300

.3.340

.1450

.3S60

.1710

.1770

.1820

.1960

.2110

.2160

.2200

.2520

.2580

.2670

.2740

.2790

.2820

.3070

.3210

.3300

.3360

.3410

.3450

,3600.3700.3830.3990.4040

44

FercentY

of

Thread

4

83.1

83.383.1

S3.283.3

83.583.2

83.483.5

83.483.3

83.883.1

83.883.1

83.183.8

83.184.1

83.8

03.184.183.883.1

83.883.984.183.082.584.5

.93.83.1

83.184.183.883.1

83,583.183.983.082.5

taxim.m

5

0:514

.0623

.0635

.0737

.0733

.0845

.0865

.0939.0968

.1062

.1079

.2240

.12E6

.1389

.1416

.3.55s

.1643

.1807

.M57

.1895

.2190

.7.229

.2258

.2630

.26E0

.2754

.28o7

.2847

.2877

.3182

.3297

.3372

.3426

.3469

.3501

.3717

.3800

.3916

.4051

.4094

Per02ntY

of

‘1’nread

6

53.0

53.052.7

53.653.9

55.756.2

57.957.9

59.1

59.7

62.8

62.1q

63.763.8

65.265.3

65.3

66.766.866.8m.1

68.6

::;68.5 ,68.5 ,.

66.7

70.0

69.7

69.069.8

69.2

69.0

70.970.870.769.869.2

7/14/2019 FED-STD-H28-2B


FED-S2D-H28/2B

m15LE 11.A.4- ~ed tde sizelimi= tefore threading for different lengths of eqag-t, sbdard

unified ard 6are IN *e&, ck 3B (see 30.1) y - amtinued.-.--

Wmmm5ed bsle size limits for different length$ of aqagenent

m a-d fnchdij-lg3.33D

~ti

7

0.g65

..0561.0580

.0667

.0691

.0764

.0797

.0849

.0894

.0979

.1004

.1040

.Ulo

.2300

.1340

.1450

.2560

.1710

.1770

.1820

.1960

.2110

.2160

.2200

.2520

.2500

.2670

.2740

.2790

.2E20

.3070

.3210

.3300

.3360

.3410

.3450

.3600

.3700

.3830

.3990

.4040

W.%ium

8

~

0.0500

.0599

.062.3

.0705

.0724

.0804

.0831

.0894

.0931

.lom

.1041

.1091

.3.348

.3.345

.1371

.3.502

.1601

.1756

.183.5

.185a

.2013

.2352

.2196

.2223

.2577

.2632

.2714

.277’2

.2817

.2E50

.3127

.3253

.3336

.3395

.3441

.3475

.3660

.3749

.3875

.40m

.4066

W 0.33Dth?uo.6m

9

~

0.0479

.0580

.0596

.0686

.0707

.0785

.0814

.0871

.093.2

.1000

.1023

.1066

.2128

.1324

.1359

.1475

.3.582

.1733

.1794

.1043

.1986

.2131

.2172

.2203

.2551

.2600

.2694

.2749

.2792

.2823

.3101

.3231

.3314

.3370

.3415

.3450

.3630

.3723

.3855

.3995

.4040

10

~

0.0514

.0618

.0629

.0724

.0740

.0825

.0848

.0916

.0949

.1o41

.1060

.3M5

.3.267

.1367

.1397

.1520

.1623

.1782

.1836

.1877

.2040

.2171

.2212

.2243

.2604

.2656

.2734

.2789

.2832

.2863

.3155

.3275

.3354

.3410

.3455

.3490

.3688

.3774

.3896

.4035

.4080

Abve 0.67Dthcu1.5D

u

~

0.0479

.0505

.0602

.0699

.0720

.0805

.0831

.0894

.0931

.1022

.1042

.1091

.1147

.1346

.1378

.1502

.1602

.1758

.181S

.1859

.2013

.2250

.2189

.223.9

.2577

.2632

.2714

.2767

.2807

.2837

.3128

.329

.3332

.33S6

.3429

.3461

.3659

.3749

.3B75

.403.I

.4054

Mxiumn

32

0.214

.0623

.0635

.0737

.0753

.0845

.0865

.0939

.0968

.1062

.1079

.1140

.2186

.1389

.1416

.2555

.1641

.1807

.1857

.1095

.2067

.2190

.2229

.225a

.2630

.2680

.2754

.2807

.2047

.2877

.3182

.3297

.3372

.3426

.3469

.3501

.3717

.3800

.3916

.4051

.4094

..

txnfm.1size in incks

ardt&ead6periJlctl

1

.062-s0r lb. 0-80

.073-64or tb. 1-64

.073-72or tb. 1-72

.096-56or W.. 2-56

.086-64or w. 2-64

.099-48 or &a. 3-48

.099-56 or W. >56

.2X+40 or M. 4-40

.3.32-4.9r f&. 4-48

.125+0 or W. 5-40

.225-44 or m. -4

.13S32 or b. 6-32

.238-40 or No. 640

.164-32 or N% S32

.164-36 or tb. 6-36

.39*24 or No. 10-24

.190-32 or W. 10-32

.2M-24 or tb. 1>24

.216-28 Oc W.. 12-28

.216-32 or W. 12-32

.250-20

.250-28

.25*32

.250-36

.33.2518

.3125-20

.33.25-24

.312528

.3125-32

.3125-36

.375-16

.375-20

.375-24

.375-28

.375-32

.315-36

.4375-14

.4375-16

.4375-20

.4375-28

.4375-32

See foomotes at eti of table.

45

7/14/2019 FED-STD-H28-2B


FE&STD-H28/2B

*5 ies

desiccation

‘3m3L211.A.4- Wc$mmcm2& hzle size limitsbefore fhrezdirqfor differentlqtba of eqqemsnt, starctard

Onifiedad s.ne 11+3ttuewfs,ck15 ~ (66230.1)~ . ~~~.- -.

.: ...

Ninor diaseterof internrdrim

NOniml size in incks —7Percenaad threads pm M of

17xecd

1

.500-32

.500-13

.500-16

.500-20

.500-26

.500-32

.5625-32

.5625-16

.5625-2B

.5625-20

.562524

.5625-28

.S62532

.625-11

.625-12

.625-16

.625-36

.625-20

.625-24

.625-28

.62532

.6s75-12

.6K7516

.6875-18

.6075m

.6675-24

.667528

.4875-32

.750-10

.750-12

.750-16

.750-18

.750-20

.750-28

.750-32

.8U5-12

.s125-16

.8125-18

.w+rn

.8125-28

.8125-32

.875-9.875-12

.875-14

.87+16

.875-18

.875-20

.875-28

.875-32

.9375-12

.9375-16

.9375m

.93-H-2a

.9375-32

2

0?s

w

lam

3aN

Lx12LXlam

32LN

lm

Zm

331m

m120NU6P

IRSm

16xmm

w2m

3am

iocU&Nw

16m

13f65

2WN

3212.’

lam

2olN

32m

See fa.tnotis at d of table.

3

~

.4100

.4170

.43m

.4460

.4620

.4660

.4720

.49s0

.5020

.5080

.5170

.5240

.5290

.5270

.5350

.5570

.5650

.5710

.5BO0

.586o

.5910

.5970

.6200

.627o

.6330

.6422

.6490

.6540

.64m

.6600

.6Bm

.6900

.6960

.73.30

.7160

.72m

.7430

.75m

.75m

.7740

.7790

.7550.7850

.7980

.8070

.0150

.8210

.836o

.8410

.8470

.8700

.8630

.8990

.9040

46

4

83.1

83.1

83.B

83.1

84.1

03.8

83.683.1

83.8

83.9

64.1

83.082.5

03.0

83.183.8

B3.I83.1

B3.1

B4.1

B3.8

83.6B3.1

83.0

83.924.1

83.0

82.5

B3.1E3.183a

83.1

83.154.1

83.6

83.6

83.1

83.8B3.9

83.0

82.5

E3.1B3.1

83.083.863.1

83.104.1

83.8

83.6

B3.1B3.9

83.0

02.5

naximm

5

in

.4223

.4264

.4434

.4537

.4676

.4719

.4843

.5040

.5106

.5162

.5244

.5301

.5344

.5391

.5463

.5662

.5730

.5787

.5269

.5926

.5969

.6085

.62S4

.6355

.6412

.6494

.655J .

.6594

.6545

.6707

.6900

.69S0

.7037

.7176

.7229

.7329

.7533

.7605

.7662

.7801

.7844

.7681.7952

.8068

.815B

.8230

.8207

.8426

.8469

.8575

.8783

.8912

.9051

.9094

6

71.871.1

71.671.3

69.0

69.2

72.2

72.1

71.971.3

70.4

69.869.2

72.772.7

72.4

72.1

71.370.4

69.8

49.2

13.0

12.872.1

71.3

70.4

69.B

69.2

13.573.3

72.9

72.171.3

69.869.2

73.5

72.9

72.1

71.3

69.869.2 ,

74.173.7

73.5

72.972.1

71.3

69.0

69.2

73.972.9

71.3

69.8

69.2

7/14/2019 FED-STD-H28-2B


2?IB2.E1.A.4- ~ lde size limits tefnre thseadiq fnr different Zerqths of e!qqe7rent, stzdard

Uoified ad sme M *e*, * 3B (= 30.11 ~ - afi~

in

.4100

.42m

.43m

.4460

.4610

.4660

.47m

.4950

.som

.5080

.5170

.5240

.5290

.5270

.5350

.5570

.5650

.5710

.5800

.5660

.5910

.5970

.62oo

.6270

.633o

.6420

.6490

.6540

.6420

.66oo

.6820

.6900

.6960

.7230

.7160

.722o

.7450

.757fJ

,7580

.7740

.7790

.7550

.7850

.7980

.8070

.8150

.B21O

.12.360

.8410

.8470

a

.8700

.8830

.0990

.9040

* 0.33D

----

._n=+-@=o Im2e size limits 20? different h

mamlti

mximm

8

511

.4161

.4225

.4371

.4498

.4645

.4691

.4783

.4994

.5065

.5123

.5209

.5270

.5316

.5328

.5406

.5617

.569o

.5748

.5834

.5895

.5942

.60~

.6241

.633s

.6373

.6459

.6520

.6566

.6481

.6652

.4866

.6940

.6998

.7145

.7191

.7276

.7491

.7565

.7623

.n70

.7816

.7614

.7900

.8022

,8116.B190

.8248

.8395

.8441

.8524

.8741

.8973

.9020

.9066

Ak& 0.33Dthru0.670

‘Junimm

9

~

.U29

.41%

.4347

.4477

.4620

.4665

.4753

.49n

.5043

.5102

.5186

.5245

.5290

.5298

.5377

.55%

.5669

.5727

.5622

.5670

.59L5

.6001

.6219

.6294

.6352

.6436

.6495

.6540

.6449

.6626

.6644

.6929

.69n

.712U

.7165

.7254

.nii

.7602

.7745

.n90

.7580

.7874

.8000

.8094

.8169

.8227

.8370

.0425

.0699

.8739

.8852

,8995

.9040

10

~

.4192

.4234

.4395

.4517

.4660

.4705

.4813

.5017

.5066

.5142

.5226

.5285

.5330

.5360

.5435

.5640

.5710

.S167

.5651

.5910

.5955

.6057

.6262

.6335

.6392

.6476

.6535

.6580

.6513

.6680

.6887

.6960

.7017

.7160

.7205

.7303

.7512

.7585

.7642

.7785

.7830

.7647

.?926

.8045

.8137

.8230

.8267

.8410

.8455

.8550

.8762

.0892

.9035

.9080

h of engagmt II ‘“

~

.4160

.4226

.4371

.4497

.4636

.4679

.4703

.4994

.W65

.5122

.5204

.5261

.5304

.5329

.5405

.5430

.5609

.5747

.5629

.5806

.s929

.6029

.62U

.6314

.6372

.6454

.6523

.6554

.6481

.6653

.6065

.6939

.6997

.n36

.7179

.7276

.7490

.7564

.7622

.7761

.7804

.7614

.7900

.8o23

.6135

.8189

.8247

,8306

.8429

.0521

.8740

.8872

.90U

.9054

9[ ]~

.4223

.4284

.4419

.4537

.4676

.4724

.4043

.5040

.5106

.5162

.5244

.5301

.5344

.5391.5463.5662

.5730

.5787

.5869

.5926

.5969

.608S

.6264

.6355

.6412

.6494

.6551

.6594

.654s

.6707

.6908

.6980

.7037

.7176

.722.9

.7329

.7533

.76o5

.7662

.-2801

.7044

.7681

.7952

.8068

.8156

.8230

.8287

.8426

.8469

.8575

.8783

.8932

.9051

.9094

.50C-12

.500-13

.500-16

.500-20

.500-2E

.500-32

.5625-3.i

.5625-16

.5625-18

.5625-2o

.562>24

.5625-24

.5625-32

.625-11

.625-12

.625-16 #

.625-18

.62520

.625-24

.625-28

.625-32

.687+12

.6875-16

.6e73-le

.687520

.687>24

.6875-28

.~7>32

.750-10

.75C-12

.750-16

.75C-18

.75C-20

.750-22

.750-32

.622512

.8225-16

.222518

.8225-20

.8225-28

.W25-32

.875-9

.875-12

.875-14

.875-16

.875-18

.875-20

.875-20

.875-32

.9375-12

.9375-16

.9375-20

.9375-28

.937+32

47

7/14/2019 FED-STD-H28-2B


lSi3U?11.A.4- 3@mmemW Me sizeM&its bzforethreadfrqfordifferentlerqthzof qagemmt, scacdac.Mfied md ~ ~ t32re2&,chzss33 (see30.1)IJ - -~~,. -

z. ...

Wdl-la3size In inchesaldtlu.xrMper&ch

1

1.000-8l.om-lz

1.000-141.00U-16

I.me-u

1.Ore-20

l.mo-a

1.OCC-32

1.0426-01.0632?-22

1.0623-14

1.0623-16

L.0625-261.062!+20

1.06.2!+26

1.225-7

1.123-s

1.325-321.12S-161.US-1a

1.12.%241.226-28

1.2.S7H1.2s73-121.167>16

1.1876-161.367s-m

1.1873-26

1.350-7

1.LE.O-8l.mu1.250-16

I.nc-in

1.250-201.250-26

1.3226-81.3326-321.3225-16

1.3123-241.3125-201.3323-26

1.37+61.373-8

1.376-12

1.373-161.373-18

1.375-201.373-28

i.4373-6

1,4315-8

1.4373-121.4375-16

1.4373-38

1.4376-m

1.4376-20

see fwbwtes at erd

5sriesLkignrttim

2

w

LP2F

m

lWN

UmP2m

Jam

m

Km

W4Flmm

[email protected]

mlmlaw

2um

mc

amLQrlRNmm’

2m

maam

mlKNUNm

‘3uLN2m7N

a

m

Uz31

lQ.7NmmZfxm

2MN

tie.

Hirnrdimreterof internaltk.s

3

.8650

.9100

.9230

.9320

.940d

.9460

.9610

.9660

.9370

.97m

.9850

.9950

loom1.Oow

1.0240

1.0320

:.09701.12001.1270

1.13301.1490

1.0950

1.11501.16001.18m1.1900

1.19601.2110

1.1770

3.22m1.2450

1.25201.2528

1.2740

1.39s01.2400

1.28501.30701.3160

1.32101.3360

1.25’701.3020

1.3470

1.3700

1.37701.3830

1.3990

Fwca-.&of

‘nuerd

4

83.183.1

83.083.B

83.103.1

S4.1

83.8

63.4

83.683.5

83.1

83.B03.9

83.0

e3.5

83.1

83.1

83.8e3.183.1

84.1

83.4

83.683.1

63.s83.983.0

83.5

63.1

83.183.8

03.1

23.184.1

a3.483.683.1

03.8

83.903.0

83.183.1

63.183,883.1

63.184.1

83.483.4

03.6

83.1

03.683.9

83.0

2/16ZL131US

5

in

.E797

.9198

.9335

.9400

.9600

.9531

.9676

.97L9

.9623

.9823

.9940

1.0033

1.01051.0162

1.0303

1.06721.10731.12S31.1355

1.1U21.E51

1.3125

1.12971.169S1.190s1.3980

1.m371.2176

1.3.9221.23231.2533

1.2KD51.2662

1.2801

1.23461.2547

1.29481.315=91.32301.32s71.3426

1.2771

1.3172

1.3573

1.37031.28551.39121.4051

FerQntYof

nued

6

74.1

74.173.8

72.9

72.1

71.3

69.8

69.2

7d.1

74.173.8

72.9

72.171.3

69.8

-34.174.1

14.L12.9

72.171.3

69.8

74.1?4.172.9

%:

69.8

14.1

74.1

14.172.972.1

71.3

69.8

74.1

74.172.9

72.171.3

69.S

74.174.174.1

72.972.1

71.369.6

74.114.1

14.1

72.9

72.171.3

69.6

48

7/14/2019 FED-STD-H28-2B


22!&E 11.A.4 ; ~ tule Size limits befnre thre.dq @r different kqti of engqeuent, stardard

13nifiedad snm W thzezdz, c3dss 3 (3ee 30.1) lJ - m~~

Iulesize Ltiitsfordifferentk

m d Inclldlng0.320

Mnimm mximm

~ of~t

AtOw o.6m tflc”1.50

, .,

bird sizein fnches

ard threadsPL?ri.mh

)JDve 0.330 thru 0.670

Rlnim.m Faxham !linimm

32

.8%.

.9148

.9271

.9365

.9439

.9497

.9636

.9679

.9347

.9773

.9896

.99901.0064

1.0123

1.0261

0.9789.9972

1.03981.0625

1.06891.07471.0886

1.05971.1023

1.32401.3314

1.13721.2.5U

L.1039

1.12221.164s1.3S65

1.19391.39971.2136

1.18471.22731.2490

1.25641.26221.n61

1.20461.24721.289S

1.3133

1.3M91.32471.33B6

1.2671

3.30971.3523

1.37401.38141.3872

:.4011

mximm

12

.8:7

.919B

.9335

.9408

.9400

.9537

.9676

.9729

78

.0s2

.9148

.9271

.9366

.9440

.9498

.9645

.9691

.9347

.9773

.9B96

.9991

1.0065

1.0123

1.0270

0.9790.9972

1.03981.0616

1.0690

1.07481.0095

1.05971.10231.12U1.33331.1373

1.2.520

1.1040

1.12221.1648

1.3.s661.39401.:9981.2345

1.1047

1.22731.2491

1.2S65

1.26231.m70

1.20461.2472

1.20981.33.36

1.31901.3248

1.3395

1.26711.30971.3523

1.37411.38s1.38731.4030

9

.8:4

.9123

.9269

.9344

.9U9

.9477

.9620

.9665

.9309

.9748

.9874

.99651.0044

1.0102

1.0245

0.9747.9934

1.03731.0594

1.0669

1.07271.CS70

1.05591.0998

1.12291.12941.33521.1495

1.0997

1.32841.1623

1.le441.19291.19771.2120

1.1809

1.22481.2469

1.25441.26021.3745

1.19961.2434

1.28731.3094

1.31691.3237

1.3170

1.26221.30591.3490

1.37191.3794

1.38521.3995

10

fn.8759

.9173

.9293

.9387

.9460

.9517

.9660

.9705

1

.8:0

.9100

.9220

.9320

.94M

.9460

.9610

.966o

.9270

.97m

.9850

.9950

1.00201.0020

1.0240

1.00+8

1.000-121.00W141.00v-16

1.OM-lS1.000-20

1.OW-26

1.000-12

1.0S5-9

1.062S-12

1.0435-141.0625161.0635-18

1.0625-20

1.0625-28

1.125-71.32581.12512

1.225161.125-3.6,

1.125-201.133-28

.9364

.9798

.9918

1.0012

1.00851.0142

1.02$25

.9422

.9833

.99401.00331.0105

1.0162

1.0301

0.9700.9900

1.03501.0570

1.0650

1.07101.0860

0.98331.0009

1.04231.CK37

1.0710

1.07671.0910

0.90751.00471.0448

1.06581.0730

1.07871.0926

1.06341.1048

1.1i521.1333

1.13921.3.335

1.1083

1.12391.1673

1.18871.19601.20171.2160

1.06721.10731.13431.13551.14121.2551

1.1875s1.3675-12

1.1875161.2272-321.1075-201.3.87+28

1.2225

1.1W71.16981.1908

1.19801.20371.2176

1.250-7

1.250-01.25C-121.350-161.2X-181.250-20

1.250-28

l.lno1.22201.24501.2520

1.1884

1.22981.2522

1.25851,26421.2785

1.29221.23231.2533

1.26051.26621.2801

1.3125-81.31>121.312516

1.31~25-le1.3125201.3135-28

1.2ss01.2740

1.20961.2509

1.29231.3137

1.37.:01,3267

1.3410

1,2721

1.31341.35481.37621.3835

1.30921,4035

1.21461.25471.29481.3158

1.32301.32871.3426

1.375-6

1.373-81.375-12

1.37516

1.375-181.375-20

1.375-28

1.19501.2400

1.285o1.3070

1.31501.3210

1.3360

1,25701.30201.34701.37001.37701.30301.3990

:.27711.31721.3573

1.3783

1.38551.39121.4051

1.4375-61.4375-E1.437+121.4375-161.4375-18

1,4375-201.4375-28

See fcotmtes at end of *e.

49

7/14/2019 FED-STD-H28-2B


FED-S’IWH2i3/Z3

‘27WLE11.A.4 - maurendd Imle size limits &fore thretiimg for different lerqths of erqagecent, stamdrd

Unified UX5 scue m thmaka, * 38 (.80230.1) ~ . ~tin~

.- -.

.=. . ..

nternd thred3

fAmina3sizo b, Ltis

C.n5threadspesindl

1.5470-61.500-81.50C-32

1.500-16

1.600-28

1.50C-20

1.50C-28

1.5635-61.5625-61.5625-12

1.5625-161.5625-18

1.5625-20

1.625-61.625-81.625-13

1.623-16

1.625-181.625-3Q

1.6875-6

1.6875-81.6875-11

1.6875-161.6875181.6875-20

1.75C-51.750-6

1.75C-8

1.750-121.750-161.750-20

1.B125-61.8125-81.Lu26-12

1.8125-161.8125-20

1.m25-d1.6325-61.8125-221.6225-161.0225-20

1.9375-61.9375-0

1.9375-121.9375-161.9375-20

2.00C-4.5

2.000-6

2.MO-8

2.000-122.000-162.000-20

%, iesdesignatm

2

oxW8IO@

16WN

m

m

m&mlmll

la

In&P2L2m

UC

m12LNl am2LI.54

ml

13W+

lam

L%mmlam2ow4

mmmlam

lam201M

2.0623-16

Se8 fcotnotes at ez-dof talzk.

w

~

1.32001.36S0

1.62001.4320

1.4400

1.44601.4610

1.38201.42m1.47m

1. 49s0

l.zom

1.5080

1.44;01.4900

1.5350

1.5570

i.%%1.5710

1.5a701.55201.5970

1.62001.627o1.6330

1.53401.s7001.63501.6600

1.6am1.696o

1.632o1.6770

1.72201.74301.7580

1.695o

1.74m

1.78501.8070

1.8210

1.15101.8020

1.84701.81001.8830

1.75901.820U

1.S650

1.9100

1.93201.9460

1.9950

83.1

83.1a3.1

03.8

03.1

83.184.1

63.483.4

03.6

83.1

83.8

83.9

83.1

83.183.1

03.8

83.183.1

03.483.483.683.1

83.883.9

83.183.183.1

83.183.803.1

83.483.4

83.6

83.183.9

03.1

83.183.1

63.s83.1

83.483.4

83.683.103.9

03.583.1

83.1

83.1

83.683.1

83.1

Y

5

L3

1.33%1.3791

1.63s81.440a

1.4480

1.4537

1.4636

1.40231.44221.4823

1.5033

1.52n5

1.5162

1.46461.50471.5448

1.5659

1.57301.5787

1.57/11.56721.60731.6383

1.63551.6h12

1.5575

1.58%1.62971.6698

1.69081.m31

1.65211.69221.7323

1.75331.7662

1.7146

1.75471.7940

1.815%1.8287

1.77711.0172

1.85731.87831.B912

1,70611.83%

1.8797

1.92981.9408

1.9537

2.0033

9wmltYof

mrezd

6

74.174.1

74.1

72,9

72.1

71.3

69.8

74.174.1

14.172.9

72.1

71.3

74.114.174.1

13..9

72.1

n.3

74.174.174.172.9

72.171.3

74.174.114.174.1

72.971.3

74.114.1

74.172.971.3

74.1

74.174.1

72.971.3

74.174.1

7<.172.971.3

74.174.1

74.1

74.1

72,9

71.3

72.9

50

7/14/2019 FED-STD-H28-2B


FEE+lD-H28/2B

‘mEG? 11.X.4 - ~ bale size 1hits before threading for different lengths of engagement, starxkd

Unified ard - U2G threa5s, class 30 [see 30.1) ~ - -t~~—-

~ed hale size Mm.@ fur difierent 1,

7“

in1.3200

1.3650

1.4100

1.4320

1.4400

1.4460

1.4610

1.2s201.4270

1:4720

1.4950

1.5020

1.5080

1.44501.4900

1.53301.5570

1.5650

1.5710

1.50701.5520

1.59701.62U0

1.6270

1.6330

1.5340

1.5700

1.625o

1.6600

1.68201.6960

1.6320

1.6770

1.72X1.7450

1.7580

1.6950

1.74001.7850

1.8070

1.82L0

1.7570

1.0020

1.8470

1.87001.8e30

1.1590

l.ezoo1.86s0

1.91001,9320

1.9460

?

~

1.3296

1.37221.4148

1.4366

1.44401.449e

1.4645

1.39221.4347

1.4773

1.4991

1.5065

1.5123

1.45461.4972

1.539e

1.5616

1.5690

1.5?48

I.wfL.5597

1.60231.6241

1.63=

1.6373

1.54551.5796

1.6222

1.6648

1.6e661.6998

1.6422

1.6847

1.72731.7491

1.7623

1.70461.7472

1.789e

1.0116

1.8248

1.7671

1.80971.8523

1.e7411.0873

~.nn1.82961.8722

1.9148

1.9366

1.9498

1.9991

k 0.33D W“ 0.67u

Minimm

~

1.3246

1.3624

1.42.23

1.4344

1.44L9

1.4477

1.4620

1.3871

1.4309

1.474e

1.4969

1.5044

1.5102

1.44%1.4934

1.5373

1.5594

1.5669

1.5727

1.5222

1.5559

1.599B1.6239

1.6224

1.6352

1.53951.5746

1.6184

1.4623

1.68441.69n

1.6371

1.6809

1.7248

1.74691.7602

1.69961.7434

1.7e73

1.8094

1,E227

1.7621

1.8059

1.0498

1.n7191.B852

1.7661

1.8246

1.e6e41.9123

1.9344

1.9477

1.9969.9950

see fmlnotesat end of m.

UAnnm

10

-m

1.3346

1.37591.4173

1.A387

1.446o

1.4517

1.466o

1.3971

1.4324

1.479e

1.5012

1.5085

1.5142

1.45961.6009

1.5423

1.5637

1.5?10

1.5767

1.5223

1.5634

1.60481.6262

1.63331.6392

1.5525

1.5S46

1.6259>.6673

1.68871.7017

1.6471

1.6884

1.7W81.7512

1.7642

1.71796

1.7502

1.7923

1.8137

1.8267

1.7721

1.8134

1.e548

1.87621.8892

1.71941.0346

1.8759

1.91731.93e7

1.9517

2.0012

—

Ch9 of engagemnt

P&W 0.6772thm 1.50

1.;96

1.3723

1.414B

1.4365

1.4439

1.4497

1.4636

1.3922

1.4347

1.4773

1.4990

1.5064

1.5322

1.4S461.4972

1.539e

1.5635

1.56e9

1.5747

1.5171

1.5597

1.60231.6240

1.6314

1.6372

1.5455

1.5?96

1.62231.6640

1.68651.6997

1.6421

1.6047

1.72731.7490

1.7623

1.70461.7472

1.7e9a

1.8125

1.s247

1.7671

1.0097

1.8523

1.87401.8872

1.7728

1.8296

1.87221.9148

1.9365

1.9497

1.9990

12

~—

1.33961.3797

1.4198

1.44001.44ed

1.4537

1.4676

1.402L

1.44221.4822

1.5033

1.5105

1.5162

3..4646i.5047

1.5446

1.5658

1.5730

1.5787

1.5271

1.5672

1.60731.6263

1.6355

1.6422

1.5575

1.5E961.6397

1.6698

1.69081.7037

1.6522

1.69221.7323

1.7533

1.7662

1.71461.7547

1.7940

1.8L54

1.8287

1.7771

1.8172

1.es73

1.a7831.8912

1,7861

1,8396

1.87971.9196

1.94081.9537

2.0033

NAn?.1size in&sardthmods pertih

1.50C-6

1.500-8

1.50C+12

1.50C-16

1.500-18

1.500-201.5oo-2e

1.5625-6

k7625-e

1.5625-12

1.s623-16

1.562518

1.56>2S

1.625-61.625-81.623-121.625-161.623-32L.625-20 ‘

1.607H1.6075-.91.6275-12

1.687$-161.6675-18

1.6675-20

1.750-51.75+61.750-8

1.750-12

1.75C-161.75C-20

1.8125-6

1.8125-8

i.e225-121.822%161.0L25-20

1.S15-61.e75-81.e75-121.87S-161.875-20

1.9375-61.9315-8

1.937>12

1.9375-161.9373-20

2.000-4.5

2.000-62.000-0

2.000-122.0K+16

2.000-20

2.0625-16

51

7/14/2019 FED-STD-H28-2B


EED-sm-H213/273

- -.

l!ALu.2 11.A.4 -“R&rrrdd hole size limitstefarethreadingbr differentlengthsof erqag~nt, st.arti

Lhifiedad = W *e*, .=3d69= (* 30.U Y - ~~@

2.125-6

II6rJ N

.325-8 81R4.2.12522 Mm2.125-16 Mm2.125-20 2orm

2.1875-16

II w2.250-4.52.250-6

II %

2.500-42.750-43.000-43.250-4 II=

tiI diameterof internalthreads

Minimum

3

in

1.9450

1.99002.03502.0S702.0710

2.1200

2.00902.0700

2.22902.47902.72902.9790

Fercentvof

‘Iluead

4

83.183.1B3.103.883.1

83.1

83.583.1

83.483.483.483.4

s

h.

1.96462.00472.04482.06582.0787

2. 12S3

2.03612. 0!396

2.25942.50942.75943.0094

Ferrem&of

Tluead

6

74.1

74.1

74.172.971.3

72.9

74.174.1

74.174.1

74.174.1

see frxsnotes at eti of Gable.

52

7/14/2019 FED-STD-H28-2B


FED-Sl’lH28/2E

w 23.A.4=~ Me sim limitsbfnre thredhq focdifferentqtb of tcq~k, ~--

onifbd8rL2g=tkell&,c&M 2a(00e30.1)J/-amtillw2d—

~ bale slm Mni- & different luqttm of ~ II

TO ad iIY%u3~ 0.3~ II A@ve 0.3~ t&U 0.67D

7

2.3300

2.2C902.07m

2.2m2.47902.7m2.9790

26nLimmll Mnioma

in h

1.9s63 1.96%

L.9P73 1.99M

2.0396 2.03n

2.0616 2.0554

2.0766 2.0721

2.2262 II 2.3229

Z.mn

II

2.03612.07% 2.0746

m

10

h

1.95%

2.0009

2.0423

2.0637

Z.om

2.3262

2.02942.cm6

2.2539

2.5039

2.7539

3.0039

-o-~til,= I124andslx@lnimsEo

32

in1.9546

1.9977

2.039s

2.0635

2.0747

2.3260

2.02262.07%

2.24442.49442.74442.9944

in1.9644 2.Xu-4ZO047 2.22s-82.OUB 2.32s-3.22.0656 2.225-162.0787 2.225-20

2.2293i 2.387+3.6

2.0263

II2.250-4.5

2.m% 2.2s0-4

2.2594

II2s00-4

2.5094

2.7596 :=

3.0094 3.*

3f21=dlffe2ammlht=arecq+dbthemkr dXbr2rhr-fc c3aytlmofc~t badhSM3hlg o.3m. ~,t.b~mluesbr klgthaoc UqagaEnt gmlk thsn o.3m in SIZZ2S0.25 tn.

d hrocr am ti5t62 - tkt Um differertm~tbeen lidtn is - 2eso tkm 0.0060 tn. Fur dbsee

pitch ~tmti other * t.lm9Bgiven in this t8b3e, mc 30.2.

2k.3eslw Mmiil125(21rRta?r+tctladi=laticmahtlk1Lbr0tqrMrin thiatah2e mlyhc&lMrledbyuR0s

va.bs&thiswpm96&2u!er9 iwadk~ikheilnthmin tbtaae!(1) Ulthtbmpiaml

[2)wiuladi=mtAEtmtis3es9ianintI?911J [email protected]!EtH-Qiml a&iMtimti14ucb & tin ~ are&sired. ou3z:vahua3nt.tmtabf0rmalna2 oimk?sdtbml.ooin.~trJw05&tMdpu6me.)

~i m*taint&. va2mdf0rt& 4.0m3-m3+m thremf. U3f 2.OQO In S2.2m ti &e 2.c@o-m tkueti

6kam Jn the t8b2e. = Vd83S tudd thn ~: 3.6630, 3.8722, 3.8684, 3.8759, 3.8m2,3.67P7. mm pantagm of thread vLu -III Lmdmqel.

~8aw2.m ~.cau&d Offint.hpr&irq mlum. 100 prxcsnt of thred - 0.75B (m 20.2.3).

53

7/14/2019 FED-STD-H28-2B


l?EIF.SSD-H28/2B

—.--

APPENDIXB

IE.SIQ4@UNIFIED—~

40. ~. fiis apg=dix prwides guidelines which rcaybe used in thedesign of unified screw threads for threaded parts. It is not a rnardatory part

of the standard. The information IXX-Itained herein is intended for guidance

only. It supplementsinformstimrnntainedin ApperdixB ofJ@i8 Bi.1-1989.

50. General.

50.1 Intrcductim. In general,any givenprcblemin threaddesignmay te

==@ible tO ==~ mre or less Satisfacbxy sdutiona basedon thepreljndnaryselecticnof certainelem?ntaof thedesignand the prcper

adjustmnt of the O* elenmw. In othermrds, threaddesign is to a largeextentempiricaland is partiallybasedon previouse~riene with similardesignsad the j~nt of & designer. Acmrdir@y, it is not practicable

to presenta definitesystemof approachto the designof a threadedassemblybut nrely b presenta discussia of variousdesignfactirs.

50.2 Factorrelationships.The interrelationof lengthof engagement,minimmnmajordiameterof the externalthread,maximumminor diameterof theinternalthread,ard the stre@h of the assembledthrecdneeds to be urrier-sbrrlti carefullyconsideredin order to producetlm?optimumdesignof aspecialthread. It is not eccmunicalta use eithera ler@I of threadergageuent which is longerthan required @.sbor@r thanthatwhichwilldavelopthefullstrengthof theexternallythreadedmember. Otherfactors,suchas

controlof tap breakage,prcparseatingof a threadedparton a sbcul.der,he

preventirmof crossthreading,omditicns of loadingwhen the assenbl.dpartsare not concentric,SIXIpassiblecollapseof a hol.lcwxternallythreadedmmber, requirecarefulanalysisti adjustmnt of thedesignwith respecttoselectionof thediameter-pitihurbination,the classof thread,lengthof

en9a9~nt, and major and minor diametertoleran=s.

50.3”Threadfit consideratims. A close fittingthreadassemblytier acmeCcrr3iticnsay fail,whereasthe causeof failuremsy k elimina&d byprovidinga Icoserfit. A cap screwthatseatsonlyon one side of the tearingsurfaceorderthe hea3may breakoff whenthe screwis tightened.Wken a screwhas a largetearingsurfacetier the heador when the headmust be squarewith

a projectingpin, sufficientpitchdiameterclearancemust be providedto allrwfor any out-of-aqdarenessf the screwaxiswith the bearingsurfaoeurderthehead. Thus,as largea pitchdkuretertoleran~ as pcssible,togetherwith

providingpropertoleranceson squarenessof facewiththe threadasis whereseatingis reguired,may avoid thenecessityfor specifyinga heattreatedtmlt.

54

7/14/2019 FED-STD-H28-2B


??Eo-s!m-H2e/2

50.4 .Staniardthreads. use of standardthreadsis reguiredin accordanceInformationon preferredsizesad classesbr .sp3cia2hreadsith 4.q—

appeSZSin 5.1 and 5.2. Wheneverpracticable,lengthsof engagementforcc.srse,fine,4, 6 and 8 threadseriesshouldbe tetween5 pitihes- 1 l/2diamters; for all other seriesthey shouldte’betwsen“5” 15 pitches.

A&i= theseprincipleswill help keepcostsof nwinufatiread gsging

60. mtriciti of as-ly and cross threadinq.

Note: Tat& 6 of Xi&E B1.1-1989inch.deetabk.s of“O.375H,0.75Hh H

In aesemhlyad use, tk crxrbiredkmnces ad armarms on bothmatingparta shouldnot allow threadsto disengagecm o= sideW&enassemblyis

eccentric. I’& axis of the internalthreadcan be displacedradiallyfrrsacoinc~with *asisofth ex=nalthread byamaimuntequd totheaumof thepitchdizureterolerancesard the alkwame. This radialdis#acementmay be sufficient= that the flankom~t is entirelycm one sidead on the

opposi~ side the crest of the externaltbre~ will bs. in line with tl-e crest

of the uternal thread with the following results * * screw is constrained

in sti a ~sition in a tq@i hole: (1) There will & danger of aossiq the

threads in starting,iux3(2)the screwmay @ out of thetole when tensioniexertedin thisconstrained~sition. The minimumanuuntof overlapisarbitraryaml controversial,tit the followinggeneralrulecan be used in lieof mre specificdata:

* the first step to assuretk minim.nnsafe overlapon hth sidestin theassemblyisamcentric, the differencebe~ tl’eminirmmmjor ditmeterofthe externalthreadad the n!axti minor diamter of the internalthreadslmld not te less thantwicethe addendumof the externalthread(0.75E).O*rwiae stated,the sum of themajor+ iaretertoleranceand allowsnce,ifany,of theexternalthreadad the minor-diametertoleranceof the in&xnalthreadshouldnot be greaterthan4/3 the addendumof thzexternalthread,0.5H. Thisprovidestira minim.mof 50 percentthreadengagement.As the

aeccndstep,to assurethat mininunsafeoverlapon one sidewhen the assemblis ~tric, tte differencebetweenthe nbsximumitchdianeterof the internthreadand th? minimumpitchdi.amterof tk externalthreadshouldnot begreaterthan the basic threadheight (O.625H). otherwisestited,the ~ ofthe pitch-diaretertolerancesof troththreadsand theallowance,if any, shounot be greaterthan the basic tfueadheight (0.62513).Thisprovidesfm anecxx?ntricssemblyccmditionequal@ half the beic threadkight (O.3225H)

and zeromini.mmoverlapon cme side. If the resultsfrcm the limitsof size

selectedviolate& atmve rules,the toleran~s shouldbe reducedby usinga

closerclassof tolerance,assumingtolerancesconsistentwith nnnufacturngpxsibility, or a marser pitchshouldbe used to increase the amunt ofoverlap. The nujor~iametertileranceof the esternalthreador minor-diame

toler~ of th internalthreadshr@d not te less than the pitch-diaretertoleranceof tk respectivethread~ maintainthreadform. Also, it shouldbnoted that,if the toleranceon theminordiarreterf tbe internalthreadmustneeeearily be large,&s nmjor diameterof the externalthreadmust be heldclose to the msxinummajor diameterad vice versa.

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FED-SID-i128/2B

70. Str engtb factors..-

70.1 Tensilestressarea. Testa have * thatexternallythreade3psrts

fail,in tensinn.atlnadscorres@rxiQ in *, ofxntbreaded.parb.itbdiamters midwaybetweenttx?iritch& minor dtiters. Formulas(la)and

(lb)in table11.B.1providestressareatasedupn a diameterapproximstdymidwaytetkeenmininnnnitchdiameterand mininn.nninordiamter. These

formulashave been applifsluccessfullykY steel.and otiernY2b.Lswith ultimatestrengthsup to 180,000psi and are oftenused forproductacceptance.milestressareasfor s=ard sizesare tabulatedin section11 of = B1.1-1989.

70.2 Shearareasat minixmnnaterial. The gatric s~ar areaof anin~ threadat minimxnmaterialis ecaualto tb? areaof thattbreulwhichis intersected by a qlider with a dians&r equal to tbe mininm najordiareterof thematingex@’nal threadover the lengthof engagznt. This is

identifiedin figure2.B.1for a one pitchsecticmad formuhs (2S)and (2b)in table11.B.1are used forcalculation. Simil.srly,he gemretricaheararea

of an externalthreadat minimummaterialis equal tm the areaof thatthreadwhichis intersectedby a cylirderwitha dianeterequal IXJthemaxiusnninordiameterof thematinginternalthread. ‘I?& is also identifiedin figure2.B.1for a one pitch sectionam5 firnndas(4a)and (4b)in table11.B.1are

used forCalculatiral.

,.

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TABLE 11.B.1 Formulasfor screwthreadstrengthfactors

1-

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FED-!31!wIi2e/2B

TABLB II.B.2 Formulasforscrewthreaddesign

Rfe rem=90cmlh

mmbm

Kfuuee te r iatic mrmfd P=$m@

[f-l) Iuuilc Btresa, ‘zxterd.fy % -:. km (b) ~ (M) 70.6~ prt - We fms im

a

(23) ~ t ii2 a .t .m M, 5:.5:+5&

70.6exwrnally tfueafd prxt 2

?WifbSt -

0.7654~d+w]

+E

““*g

6A:fzm (,d)0, (fb)[13) Ia lgt h o f r l? 3 n gEe r lt fs s rd lt u l. r .? -

~ * fAilLUC 0~ ..&d~

70.7.3

ad Intellnlfbra

3A;frm (3A)or (lb](M] laq’tbOf0qag5mtfssmdqm m. 70 . 7 . 4

W of extxrnc.1 thread .W. fcus Na) or (w

fts

2A” fzlxl (k.) or (fb)

(M) Ia-@fl o f e rgLgrs 51 t fu se d u p 12—~ 70 . 7 . 5

dQR3 @n g fu 12 t en dle t ieq t h M frm d Mb)

o f ext urn , t .h m rd Wifb t fu tiqt -ic Si’Z3 - W vitb [161

t m s \

[16) m*Ofew+f==ntw- Iz-Izfrcm[Elx LEEu %7.5

A?arofintmnalfmuld ~ m (9)

k )

i s g r emc r t fm l

,

fbmtim: dpim - mfnimnl mlmr dirllmtic, external thcead, flat form (- K+inl . im=h.

xndmub [12),dl.nin-d+-~fl-d~-~

d h . m e diawter, ea t.c rrm lly t fxe ?d ed p ut , in ch . If tic, is M tie, db - Q

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FEtWlWH28/2S

I sEmoNmMIN,M”M I

I SHEAR AREA OF

INTERNAL TNREAD I

m““’”’ ‘

MAXIMUMMINOR OIAMETER MINIMUM MAJOR OIAMETER—

OF lNTERWALTNREAO OF EXTERNAL TNREAO

70.3 Shearareaaat basicsize. The gearetric*ar areaof an exkwnal

thread a=ic size is equal to tke area of a basicsize threadwhich is

intersectedby a cylinderwith a dianeterequalto the basicminordiameter.

Formulas(6a)and (6b)of tible11.B.1are used fircalculation.‘Fhsgecznetrcsheararea“ofan ~te&al threadat tasic size is not ordinarilyusedfor

calculations.

70.4 Sheararea simolif&~ formulas. ‘mnnulas(3)and [5) in -le 11.B.1

are sinipliied fornud.asor Internal ad external thread shear areas. They are

based upn aqirical dati ad give shear areas whichvary frmn the gecan?tricminimummaterialshearareas. In sczne-s, testdab agreesnxxe clmely

with thesesimplifiedformulashearareas thanwithgecmstricsheerareas.

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70.5 Sheararea,cabined failureof externaland internalthreads. When

themstfngexternaland internalthreadsarea partsImnufacturedfran

materialsof a~roximstelyequal strength,failurewill usuallytakeplace intoth threadssimultaneously.Threadbendingduringfailurecharxp the threadgeometryin thismae sc thateffec$ivesheararea is significantlysaaller

than tise -lculated franformulasdiscussedin 70.2,70.3ard 70.4above.Formula (7) in table11.B.1is an ~irical formulawhichgivesan approximate

equivalentfor thiscase. Numerically,it describesa failureat thepi&hdiamter of one of the threads.

70.6 ‘[email protected]. Formula (1.1)n table11.B.2is oftenusedfor

acceptanceof externallythreadedfastenerswith ultimatetensilestrength,

yield strength,or rareotherselectedstresslevelappliedto St in order bdeterminethe requiredaxialtestload. When threadsare used in a joint,atightening torque is applied to over- friction tier a tdt head or nut, b

over- thread frict ion, ard to develop the axial lcasd. This torgue results

in a shear stress, which when tiined with * tensile stress fran * axial

load, causes an increese in the effective tensile stress. Etxmula (12)in

=e II.B.2describesthis situation.Experien~ has slxnmthat for a solidexternallytbrerdedpart, theccmbinedstressis generally*ut 20%greaterthan * tensilestresscalculatedfrcxnforrmd.a(n). Therefore,in thiscase,the crrnbinedtressis oftenassuuedto be 1.2S or is not considereddue bSStisfact.myexperiencewith tbe Facimrof Safe& used.

70.7 Lenqth of engaqem?nt,LE.

70.7.1 If failureof a fasteningsystemusingstardardthreadedfasteners

shculdomur it is generallynure ecommical tit the externallythrezuiedartwill breakratir thanthateitherthe externalor internalthreadwill strip.In othermrds, the lengthof threadengagenmt stxnild sufficienttn devel.c

the fullstrengthof the screw. ‘Ihua,the lengthof internalthresdard thediuensirmsof this thread,particularlyitsmimr diameter,shouldbe suchthat,takingintoacrmunta pxsible differen~ in strengthof materialof t&internalad externalthr.swls, the threaded pxtion of tbeexternallythreadedpaxt will break before eitbsr the external or internal threads strip. Due to

this situation, lengths of engagement formulas are dez ived fr.anshear fornulas

with tensile stress area ~ replaced by X because the reguired area in

skar is twioe tlBS tensile stress area in order b develq the full strength of

* externally threaded part. This relationship is baaed upm experkmts mile

by tbe National 3ureau of Sta.r&rds in 1929, in which it was foundthat for

kt-roll@ arxlcold-rolledsteel,and brassscrewsand nuts, this factorvariedfran 1.7 to 2.0. The effectof ccmbinedstressis not tikenintoacmunt incalculationof 12?becausethe added@ear lcxd affectstoth tensileard shear

stressesin approximately the Sanb2 prqrtion.

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EwsmB28/m

70.,? :2, All Iimmlaa -r @gth of engag-t, given‘intable11.Bi2yield

apprQX_te Val= Since theyare based in part upn shearareaswtiic.h%reotexactdue to nut dilatim whichvarieswith gmtry, frictionforrs, ardmaterialproperties. Also, the effectivemssof partialthreads,in *countsrsinkfiordmnifer6)ciitliie*” of the intird thiead,‘isiiitalwaysthe Smle. For calml.atirxu3,pproximatiyba.lfthecrxmtersinkd@I may te

ccmsideredin the -lengthof ~t. It is advisablethat~tirms oflengthof engag~t and correspx-ding hd capabilitiesf a threadedjointbe

cheokedby actualtests,for criticaljoints.

70.7.3 Wls?nthe ex~y ad internallythre?skaputs are made frrml

matir* of approximatelythe same strength,requiredlengthof engagauentinformu2a(2.3)f tableII.B.2may be applied. This assumesa cmthatirzl

failureof both threads (see70.5).

70.’7.4When * strengthof * internalthreadmaterial.lvexceedsthatof

* external thread, r+ired kr@ of engagementin form& (14)of tableII.B.2uay be spplied. !RIisassuresshearof the externalthreadd usesthegecmetricshearareaof theminimumexternalthread (see70.2) . A slightly

I.mgeror abrter lengthof eng~-t will te fiicatad if the simplifiedformula(5)in Uahl.e11.B.1is used.

70.7.5 When the strengthof * externalthred materiallyexceedsthatofthe internal thread, reguired hrqth of engag~ in @rmula (16)of table11.S.2is used. This is basedqxn the internalthrezdstrippingloadM.ngequal b the ncminalexternalthred stri@ng loadwhichwilldevelcpfullstrer@ of W.externally,threadedgmrk. Zf & ia.Jaas.thsn.1,see

7.3.0.7.4ard if approximetilyequal to 1, see 70.

70.7.6 For an adjustfigor lead screwof if the ~ctim will befrequentlyunscrewed,* *ulsted IE simuldbe increasedto a.1.kwfir the

e~titear On * flanksof * threadsduringtk usefullifeof tbe.

“~0.?17:For”t&ed)n2es”in ahi?et”M, ,* kinum size of th6’screwto be~ifid stxd.db such”thatthe thicknessof sheetequak theLE requiredtodeve@ full StKel@h. In orderto use thelargestpssible screw,it isn~ssary that tbe tolerance,~, cn the minordiameterof * b.laslx.ndd

be * practicalminimun. If it should“prove.ti& inpracticahleto reduce tk

inimr diametertoleranceb sucha vslue,it may be n~ to decreasetheminimumminordizmter of tl16internalthre~ arxlto increasetb minordbtar bleranca by the:= arxnant.If this..6 daqa,..tlp.JmximumBJKdi,amStarf t.hsscrewmust be reduc@ ~“ th ~ auxwnttoprevent

interfermceaIX3the.rniuxdianeterof the ~ threadringgage must likewisete

decreiisd,as this is W cnly controlof theminordianeterof the screw. Inall awh cases,wtw?redimensionsare alteredfrrznthosecalculatedacmrding totk standard,theAQ4?.B1.1-2.989.

. . .

threadas.bu.lde designatedas specifiedin sectirm6.7of

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FEESTD-H28/28

70j.& ~r’ retainingus iiishafti“tie * ‘** aiial firce

resi-by the collaris appreciablyless thenthe tensilefir02that““the

shaftiiselfis“capableof resisting,LE need orilybe lcmg etx)qhb withstadthe expec~ axial.forcgw the mllar. If,FC is.QK axial..for~..@[email protected] themllar, UIS~ is the tensilestrengthof the shaftad W1’Sn

is the tensilestrengthof the collar,calcolatethe requiredlengthofengagenrmtfran one of the followingfornmlas:

Z?c

a. ColJ.ar thread strip: I.E=~ x ASn from (2a), (2b)or (3)

.—LE

2??=

b. Shaft threadstrip: LE =L71S5x ASS fran (4a),(4b)or (5)

zc. Cmkinatirm threadstrippingwhenWIS.s= W1’Snapproximstily:

2FC~.

UIS5or WfSn x X frrxn7)

-FE

Note: Numbers in parenthesis are &mmila v’mmtersfrcxnable11.B.l.

70.7.9 For I_dlow,thinwall threadedpertsas the wall thicknessof either

or bth the internal ad externalumbers-~s thin,the temkncy of tlEexternal mmker WY enlarge ad the internal Xremker to neckdcnm in * threcdmeans thatsn I.Egreaterthangivenby fornulamustbe used,also thatthetilersnceson minordiane@r of the intxmal threadard majordiamti of thsexternal‘thread,~ ad ‘M, must be smll to obtain* maximumpracticabledepthof threadengagement.For cxqanents having~eeds on thin-selltubing,tests@e? actualtmrkingconditionsslmld be made ti determineprqerselectirnof wall thicknesses,lengthof engagement,and pitch of thread.

80. l’bredm-qxxtims in relationto tapping.

80.1 In the productionof threadsit is rxms.ideredmpracticalto tap athreadunlessits nmninaldiameteris greaterthansix timss.the lxsicthread

height;therefore,wtr?nti ratioof D to h is less than 6, tk use of a largerdiamter, a finerpitchof ~e@, or both,s~~d te mnsidered.

80.2 ‘l’he size of9

is a factorin cmtrollingtap breakage. Tap breakageis infrequentif the larm2tirf the tap is over 0.5 in. or if the lengthof

threadto be tappedis less than0.5D. For sizeslessthan0.5 in.and length

of threadover O.5D, tap breakagecsn be minimizedby use of a largeis ~ trash.

~ that

Howsver,thismeans thatLE may have to be increased

developthe fullstrengthof * screw.

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FEO-8TD-H28/2B

,.

90.--Bxal&s Rf.hreaddesim. :... ....=.,.-

90a ‘&m &rel thread. A gun barrelis subjectedb an internalexplosivepressurethatproducesa tensilestressin the threadederd. The lengthof

~~t of the ~ ~ be -SUfficient‘toprcducea &* -~ea inshearon tk threadsof tk e.crm in line with the mi.mr di~ter of the tap~dFOle thred.sequal to twice * stressarea of the threadedporticnof *

barrel. Assume that * thread on the barrel is 1.500-8aN-fiad the minimuminternaldiaus?terf the baxrelat tte threedederxlis 0.792inch.

Note: 8ymbolKAaticm ard fornuib numters in parenthesisare inaccordancewith tables11.B.1 ad 11.B.2.

a. Pe@red lengthof engag~t is titi usingformula(14)fix al?dl.owart.

(. 2 As - o“7fJ54d;)

with~ =( \

.7854 dw - 0.9743 2. In thiscase,As may te

readas \ ni

1.492 fron table13 of ASM3B1.1-1989.

dh = 0.792

n . 8

%= = 1.390 frantable34 of ASME B1.1-l!389.

d@n = 1.4093fran tah.le3A of ASME El.1-1989.

b. Calculatingfrcsnthe atnveyieldsa requiredlengthof eqagemnt of0.777inch. By reducingthe internalthreadmi.mrdiametertoleranceby half, the resulting

?nsu is reducedto 1.3775

inches,zud the reguiredlengtho engagemnt is reducedto 0.714inch.

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90.2 screwsnmmt@ bracket.b Cask irm part. lb dimeosirm.iarequired——for the largeststsae.1sp Z= tit [email protected] ,bracketon,a.uaatira-:x@. ‘@e tgrisiletrengthof the steel is 60,000psi, the t@aile

strerigtiofthe cast iron20,000psi,SIXIthe thiclmessof the cast iion is

sti thatthe lengthof threadcmgageanenkanmt exceed1.750in. Tbe screws-.on* *.eide *f--ti-ba!*”wilJA-iJl-tassios.---.-----’-------------------

,, ... .. ..,., ... ,.. ....... .. .

~te: .Symbl mtatinn and formulanumbersin parentbesiaare in=rdane With tables11.B.1ard 11.B.2.

a.

b.

c.

d.

e.

f.

Since tkexkrnal threadnxiteridis considerablystmqer thanthatof the internalthreadmsterial,in -rdanCz with 70.7.5,

formula(16)wi.Ute usedto d.culdte the lengthof engagementrequired. This Ermmil.as appliedfor LE tasedupn shearof the

internalthreti. ‘R3rmnfirmthisasswuiptim, j 4 shoul dbeCalculated.

Rl cannotbe calculatedfrcm formula(8)untila threadsire is

selected. BY definitim, however,R1 is * ratioof ex-nal

threadsheararea ti internalthreadsheararea. M approximatioof RI, ran bereadeusing* simplifiedformulasfor shararea5 so

ApproxhsNz

~ is calculatedfran

U&

R1 .F&Ida (5) . 0.833

ZziEm

fonrnd.a (9).

%= ~;=- =0.333

Fran b end c abve, R1/R = 2.5 approximtdy. This *Wz“einggreaterthan1 m mm tbe use of formula (16) for

calculationof lengthof engagement.

. . . .

Fran formula (16)it is seen that * lengthof engageumt mustk approximately.5 timesas lmg es that requiredif shear intheexternalthreadwere tke omtrolling factor. ThusrSince*maximunavailableLE is 1.750inchs, theapproxiOataLIZrequired

for tbe screwto develrpfullstrengthis 1.750/2.5 = 0.700 inch.

J.mmuch as the hole is tappedin cast iron,a relativelycrarsethreadmuld be reguired,that is W or coarser. The matreadilyavailablescrewsvmuldbe UK. Selectthreadsi7-esfranfigure2.B.2whichyieldLE of a~roximately 0.700inch. Figure

2.B.2 was devel~ fron formula(1.5).

For 1’ - 8uK, LE/D = 0.594and LE = 0.594

For 1~- 7’UK,LE/D = 0.592 (est. and U? = 0.656

8

For lL - 70’N2,L@ = 0.600 (est.) and E = o.7504

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EZD-S7TD-R28/2B

h. The threadskouldke checkedin zciwrdancewith formula(16).Formula (16)may be exprb as follcws:

3.1416~min XL

4

(ith ~ = 0.7854 db - 0.9743)2. In thiscase,As IMy-

be read as \ ‘}0.763frr.enahl.e8 of ASMR B1.1-1989.

r+lnin= 0.970fran table34 of ASME B1.1-1989.

FOrIIU.&I (6b) +X%*‘1 = Fo@ .

.,. . . .. . . . .!n

[ 1

ihnin:ax. 0.57735 (dQin ;- I&sax)

n=7

dmin= 1.1064franixib.leA of ?!SkiEl.1-1989.

D2max= 1.0416fran We 3A of M24E B1.1-1989.

so R1 = 0.863

RI . 0.333 fK!IU *W.

i. Calcuhting frmn0s atme yieldsa requiredlengthof engagemenof 1.729 inches. This is acceptablesince it is less thanthe

masimumavailableengagmt lengthof 1.750.

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FED-Sl!D-H28/2B

tmmwcammmmm m msttn ‘am

66

(-4

!3E

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P’EMm+w29

.. - APPENDIXC..~ _=-, .. ...

AMERIC2NNWX2QLFWU4CFHREAD

100. ~. This appsrdixprovid~ gemxal informiticmatimttheobsolete

Iimericanati.trialorm screw thr~s. It is not a mardatorypsrt of thestiard. See 5.2.1 for eelecticmof atamiardlhified screwthreadclassesto

replacetheAnericanNationalform threads.

110. Profiles. Basic profile is the same as thatof M Unifiedscrewthreadexceptthat the width of the fbt at the root is 0.125P. The designpro f i le for internalthreads ia the W as thatof tbeUnifiedscrewthread,i.e., widthof flatat the root is 0.250P.

3.20. ‘llueti classes. ‘here are 5 cbaees of AmeriainNationalfbrmthreads. Ebr informatirmonClass 5, see FEM?m+28/23, C1.aSS5

Interference-Fitcrew Threads. See belowtir otherclasses.

120.1 AUowaces. my Class 1 externalthrede havean alkwmce. Class 4

externalthreadshave a negativealhance on the pitchdiametexonly.Allowancesare ehmm in Table 11.C.1.

120.2 ‘lbleran02s.Piti diaretertiler-s for externaland internalthreadsare .sl’nwnn Table 11.C.2. Externalthreadmajordiamter bkrancesfor Uaaaes 1 ad 2 equal twim theirrespectivepitchdiamebertoleranms; theClass 3 ad 4 tolerancesare the sameas the Class 2. Internalmi.mrdiam=ter

tolersrms forClasses1, 2, 3 and 4 are @ to 0.1 t~s thedesign(minimum)minor di-ters.

120.3 Formulae.

Note: Pitch,P = I./threadser inch.

120.3.J Internalthread.

Min. major dia. = basicmajordia.

Min. pitih dia. = min. majordia. - 0.649519P

Max. pitch dia. = min. pit@ dia.‘“~ fr~ TFMe 11.c.2

Min. mirxx dia. = min. msjor dia. - 1.082532P

[email protected] dia. = min. minor dia. + 0.1 (min.minordia.)

120.3.2 Externalthread.

Class 1 max. major dia. = basicmjor dia. - esl franTable 11.C.1

masses 2, 3, 4 max. major dia. = basicmajordiameter

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FBHmx328/ZB

-..—.=.

Min. majordia. = max.msjor dia.- ‘I’drcanTable 11.C.2.

Classes 1, 2, 3 mix. pitchdia.= max.majordia. - 0.649519P

Class 4 max. pitchdia. = ~. rmjordia. - 0.649519P+ esfrcnnTable 11.$.1

tlin.pitchdia. = max. pitchdia.- ‘R32frcsnTable11.C.2

Max. minordia. = max. majordia. - 1.226869P

130. Desiqnatims. StandardAnericanNstionalfirm threadsare deaignatithesaue as the Unifiedthreadsexceptthatseriesi.rxiicatircesnot we the

“Umand classdoes not have the ‘Ae or “Bm indkdth fix “external”ormintermal=.Thus, a stam3ardthreaddesignaticmmight read ‘1/2-131?l-2m,rexmple. A seriesdesigmstor‘W” is used for ~ial crmhinatima ofdiaueters,pitchesad lengthsof engagmnt.

140. -es. ~es are designedin ~rdance with tteprinciplesof Unifiedthr~ gagedesign. See ~8/6, Gagesand GagingfirUnifiedScrfiwThreads- UN ad UNR ThreadForms.

,..

68

,., ,.,

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I?Ews!m+128/2B

‘ “ “TRBLE 11.C.1- Albwance forAuericanNationilScrew‘?lhreiuk:._.=.

Threads“per

inch,tpi

8072

645648

4440

36

3228

24

20181614

1312

II

10

9

8

7654 l/24

0.0007

0.0007

0.0007

0.0008

0.0009

0.0009

0.0010

0.oo1.1

0.oo110.0012

0.0013

0.001.5

0.0016

0.0018

0.0021

0.0022

0.0024

0.0026

0.0028

0.0031

0.0034

0.0039

0.0044

0.0052

0.0057

0.0064

.Class 4 negative

allWanCx2 , es4

inch

0.0002

0.0003

0.0003

0.0003

0.0004

0.0004

0.0004

0.0005

0.0005

0.0006

0.0006

0.0007

0.0008

0.0009

0.0010

0.oo1.1

0.0013

69

7/14/2019 FED-STD-H28-2B


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Threads

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class 1

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0.0024

0.00250.00260.00280.0031

0.00320.00340.00360.00380.0043

0.00460.00510.00570.00630.0070

0.00740.0079

0.00850.00920.0100

0.o1.1.10.01240.01450.01690.01840.0204

Class 2

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inch

0.0017

0.0018

0.0039

0.0020

0.0022

0.0023

0.0024

0.0025

0.0027

0.0031

0.0033

0.0036

0.0041

0.0045

0.0049

0.0052

0.0056

0.0059

0.0064

0.0070

0.0076

0.0085

0.0101

0.0116

0.0127

0.0140

claaa3

m@32

inch

0.0013

0.oo13

0.0014

0.0015

0.0016

0.0016

0.0017

0.0018

0.oo19

0.0022

0.0024

0.0026

0.0030

0.0032

0.0036

0.0037

0.0040

0.0042

0.0045

0.0049

0.0054

0.0059

0.0071

0.0082

0.0089

0.0097

class 4

‘rD#rd2

inch

0.0011

0.0012

0.00).3

0.0015

0.0016

0.001.8

0.001.9

0.0020

0.0021

0.0023

0.0024

0.0027

0.0030

0.0036

0.0041

0.0044

0.0048

E&r

class1

m

inch

0.0048

0.00500.00520.00560.0062

0.00640.00680.00720.00760.0086

0.00920.0102

0.0114

0.0126

0.0140

0.0148

0.0158

0.0170

0.0184

0.0200

0.0222

0.0248

0.0290

0.0338

0.0368

0.0408

1 threada

;laases2,3,4,

‘m

inch

0.0034

0.0036

0.0038

0.0040

0.0044

0.0046

0.0048

0.0050

0.0054

0.0062

0.0066

0.0072

0.0082

0.0090

0.0098

0.01040.0112

0.01.18

0.0128

0.0140

0.0152

0.0170

0.0202

0.0232

0.0254

0.0280

1/ MinordianAer tolerance for internal thread is one-tenth of the.minimumminordiameter.

70

7/14/2019 FED-STD-H28-2B


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