british time and percussion fuzes

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L. MORTAR.

34

CHAPTER IV.-TIME FUZES.

LARGE NORTAR 1111 M-11:11ALL A MSTAR FUZZ.--.-DIAPIIRAON SHRAPNEL-

FUZE.-COMMON FUZE.-M. L. FUZES, 5, 9, AND 2 0 SECONDS.-

B. L. Fuzes, 5, 9, AND 2 0 LINCONDS.--RULES AS TO LENGTH OF

F U Z E AT VARIOUS BANGF.8.-ARNEITRONG E. TINE FUZE.-HAND--

GRENADE FIIZZ.-PARACIITTE FUZES.

The large mortar fuze is used with 8", 10", and'13" m ortar shells, its construction is shown by thefigure (see cut), the head is protected by a pure tincap and disc of pasteboard which are removed bymean s of the tape when the she ll is placed in themortar. Ignition is secured by means of quick-match prim ing, and also by the hole in the top of the faze compo sition. The compo sition is driven ina channel bored in the centre of the wooden cone ;its length being 6 inches, the fuze burns 30 seconds.The figures on the fuze refer to the inches of com-

position, but, as before pointed out, by adding acypher they will refer to the general half-secondunit ; only five divisions are m arked to the inch, Bo-th° fuze reads to seconds, there are no holes boredat the marks on the fuse, but only indentations.The fuze is bored through at 6 inches (in futuremanufacture a pellet will be inserted as in ,tbe20-second s fuzes, p. 38), so that it will act withoutboring at this length : the first hole marked forboring is at 2".

The first ring on this fuze serves to matk thedepth it will enter the fuze hole of 13" and 10"mortar shell, below this at a distance of •9" anotherr ing marks w here the fuze is gr ipped by 8" shel l .The first hole will only act in the 10" shell, as itfalls against the metal in the 13" and 8" shells.For preparation, and implem ents required in prepa-ration, of this fuze, see p. 67.

The fuze is ignited by the flash of the dischargeand burns till the flame reaches a bored hole,

through which it passes and explodes the shell.Packed in whole size metal-lined case holding 330 .



S. -MORTAR. Small mortarf u s e .

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1,000 in metal-lined case, but in future will be , Issue.

issued in tin cylinders holding five fuzes.Diaphragm Fuse, used for diaphragm Shrapnel shell. Diaphragm

The arrangem ent for protecting the head, and for the Shrapnel fuse.

ignition is similar to that given above. Fou r holes are p / Abored through the tap of the fuse to secure the quickmatch . The channel for the fuze composition is bored

eccentrically so as to give space for two powder DIAPHRAGMchannels, one of wh ich is shown in the section (seeeat). The main channel is driven with fuze com-position, the powder ch annels are filled with pistolpowder, and the powder in each chann el is supportedby a piece of quickmatch.passing through the lowesthole, by mean s of which the flame explodes the shellif the fuze is not bored. A groove cut in the bottomof the fuze with a piece of quickmatch laid in itunites the two powder channels. Holes are boredthrough into the pow der channels, filled with powder,and protected by clay being pressed upon them.They are covered externally by varnidhed•paper.

The powd er channels ate useful, because (1) hi case of the hole bored

com ing in contact w ith the metal of the shell they carry the flash to thecharge ; (2) by having the odd num bers marked on one chann el and theeven on the other they allow sm aller divisions to be marke d, readingto half-seconds ; (8) because with Shrapnel shell a powerful flashis necessary to ensure the powder igniting, owing to the construction of the shell.

The length of fuze compo sition is one inch, the fuze burns 5 secon ds,and it is marked on the side channels up to 10 halhseccmds.

For preparation, and im plements required in preparation, of this fuze,see p. 64.

The f lame from the fuse com posit ion ignites the powder in one of Action.the channels at the point where the fuze has been bored, whichexplodes, giving a strong flash through the bottom holes, and bothchannels explode together as they are connected by the quickm atch at

bottom.See page 28.

Common Fuze, used with S.B. common shell • (see cut). The con- Common fuze.

• The 5, 10, and 15 seconds fuses, which were iss ued sp ecially for the 7-pr. gun, § 5097.may be u s e d with S.B. comm on shells, as they are obsolete for the 7-pr., which hasno w the G.S. page. They resemble Mart U. M.L. fume, but ar e of the comm ongauge.

Small Mortar Fuze, used with 24-pr. and 12-pr.com mo n shellfired 'from •5i" royal, and 4-1" coehornmortars respectively st long ranges (see cut). It isof the same Fan g° as 'the comm on faze but longer,containing 8 inches of fuze •com position burning 15seconds; its marking an d construction are similar tothe large mo rtar fuze, therefore the intervals betweenthe holes correspond to one second of time in burning,the first mark for boring - is at 1 inch.

When used with the 12-pr. shell a piece of rag,

gaper, &c., must be w rapped round the fuze to make

SHRAPNRL.

Issue.

C 2



C O M M O N .

36

rue.

M.L. fuses.

Regulationsfor issue.

straction is the same as the diaphragm fuze, except thatthe powder channels are not connected at the bottomby quickmatch, but are stopped with she llac putty. Itcontains 2 inches of composit ion and burns 10 seconds ;the preparation and action are identical with the dia-

l) fuze. This fuze would be used instead of thesmell m ortar fuze, when 12-pr. and 24-pr. shel ls are f i redat short ranges out of the 41 and 4-inch mortars.The common fuze may also be used with 100-pr. dia-

phragm Shrapnel shell.See page 28.It is i mportant to have a clear idea of the difference

between the various Ma rks of M.L. fuzes as they cann otbe used indiscriminately. The dif ference between M arksI. and II. is in the amount of priming and in the m ann er

of protecting it. The p riming in Mark I. was found not to ignite withcertainty when sm all charges were used, therefore Mark IL was intro-duced , having an inc reased quan tity of priming w rapped round the groovein the neck of the fuze, this caused a p rojection, over which the copperstrip used in Mark I. could not be p l a c e d,*

with a tape band only, andir:it* so Mark II. has the priming

so well protected against risk ,

from fire, when placed in the shell, as Ma rk I. ; it has, however, theadvantage of acting with sm all charges, such as a re used with fieldguns . It was obviously an inconven ience to have two fuzes, one forfield service, and the other for garrison service, therefore Mark III. hasbeen in troduced, which will ultimately become the only pattern forland service.

Several imp ortant changes have been introduced in Mark III. They are more certain of ignition, will be less likely to cause

prematures, and stand climate better than the previous patterns, from which they differ as follows :-

1. The hea d projects a little farther from the shell,t has a largergroove containing the quickm atch priming; and differs fromII. n having a copper band: protecting the priming .

2. The paper lining is reduced by one-half its thickness, andis coated with varnish. It is hoped that this may prevent thefuzes from deteriorating, as Marks I. and IL are liable to do inkeeping.

3. The powder channels are brought nearer to the centre of thefuze, and are slightly reduced in length ; thus protecting the powder from the chance of being ignited by the discharge of the gun. The side holes are not bored beyond the powderchannel. The bottom side hole is num bered.

The chang es in the 20-seconds fuze are similar to those in the short-range fuzes, excepting of course the powder channels.

The following are the regulations for the issue of the various Marksof M.L. fuzes.

• The copper strip used in Mark I. fuzes is 1" broad, the one used with Mark III.fuses is •42-. Possibly this increased width would have enabled it to be used withthe Mark H. fuzes.

t The length of 5-seconds and 9-seconds fuzes is in creased by •5" at the top,that of the 20-seconds fuze by •1". The diameter of the h ead of the 20-secondsfuze is increased by •021". The increase of length facilities ignition and makes thefuze easier to uncap.

The protecting band is of copper, coated with india-rubber solution, between twothicknesses of tape.

1 2483.2622.



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Fuzes of Mark I. (§§ 1417 -1953) will be retained in the service, and § 2481supplied to the Navy for use with all rifled M.L. guns, other than 12622.boat and field guns; and also, so long as these fuzes are availablein the district, for land service for the 64 -pr. and 80-pr. B.M.L. gun sonly.

Fuzes of M ark II. (§§ 206 4-207 1) will, until the store is exhausted,be supplied for land service, and for naval service for boat and fieldguns.

Mark III. will be the only fuze m anufactured in future for LS.*

Marks II. and III. are to be supplied to the Navy when Mark I. is notavailable.

5- seconds M.L. Fuse.— For shells with which this fuze is used, seetable, p. 58. For construction and general arrangements see plate,p. 851.

They resemble those of the comm on fuze, but the head is closed by agun-m etal plug, round the pin of which quickm atch is looped an d ledthrough two fire holes to a groove.

This arrangement of the head ob liges the fuze to be longer than thecommon fuze.

A paper lining is introduced to prevent the formation of a spacebetween the wood and th e composition in the event of the wood shrink -ing, which would cau se the fuze to act prematurely. .

The clay, stopping in the side holes is dispensed with, and varnishedpaper alone covers them and the powder chan nels, which are united byquick m atch at the bottom of the fuze.

The fuze is driven with m ealed powder, which, as it burns at twicethe rate of fuze compo sition, allows the fuze to be graduated, so thatthe interval between two consecutive holes corresponds to quarter-seconds time of burning. The marking of the fuze commences at 1,

and the side holes are numbered 1, 1.5, &c., thus enabling the fuze tobe bored to q uarter-seconds ; the integral figure referring as in otherfuzes to half-seconds.

It is necessary to be able to burst F.S. Shrapnel shell with greataccuracy to develops their power, hence the advantage of this fuzefor F.S. See p.159.

9- seconds M.L. Fuze.— For shells with which this fuze is used, seetable, p. 58. For construction and general arrangements, see p late,p. 851.

This fuze, though called a 9-seconds fuze, will when at rest burn10 seco nds. It contains 1".8 fuze compo sition, above wh ich is drivena pellet •4" long of mealed pow der (equal in time o f burning to -2" fuzecomposition). This is done to obviate the risk of cracking the

composition, when boring for short ranges, a result liable to occurwhen there is only •2" of composition over the top side hole. Theconstruction and size of this fuze are identical with those of the5-seconds fuze, except that fuze composition is used instead of mealedpowder, and uently the side 'holes are marked to half-secondsonly, as shown in e plate, p. 851.

§§ 2486, 2622.

§ 2707.

6- secondsM.L. fuze.§§ 1953, 2061,2484.

9.second•M.L. fuze.§§ 1236, 2061,2622.

This also applies to 8.8. for boat and field guns. §§ 2485, 2622.



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20-seconds 2 0 - s e c o n d s . Fuse.— For shells with which this fuze is used, seeM.L. fuze. table, p. 58. For construction and general arrangem ents, see cut.

§§ 1417, 2071, 20-Sec, M.L. Mark I.2485.

Action of th eM.L. fuzee .

B.L. fuzes.

It has 4 inches of fuze com posit ion, on the top of which is •5" ( in' Marks I. and II. .1") of mealed powder, through which the smallhole to ensure ignition is bored* Its general construction an d actionresemble those of a m ortar fuze, as it has no powder chann els ; bat the

l

as to priming, paper lining, &c., are the same as in othera

MrTrt

i elitli

zi

es . It has a pellet of mealed pow der, pierced, as shown in thesection, tocarry the flash from the bo ttom of the fuze into the burstingcharge of the shell.

The m arking begins at 20, and reads to even half-seconds only, as itrims 20, 22, &c.

When the fuze composition becomes i g n i t e d , it burns out of the twofire holes provided for the purpose, in other respects the action resemblesthat of the diaphragm fuze (p. 85), except the 20-seconds, which_ actslike the large mortar fuze (p. 34).

The B.L. fuzes resemble the M.L. Marks I. and II., except in theconstruction of the head.

As there is no w indage in B .L. guns, their fuzes have to be ignitedby a detonating arrangem ent which is described below. There is onlyone Mark of the 5-seconds fuze, but of the 9 and 20-seconds fuzes thereare two. Mark I. 9 and 20-seconds had n o safety pin, but had a kamp-tulicon disc on the top and b ottom, so as to lessen the chan ce of theirexploding if accidentally struck. Mark II. has a safety pm as describedbelow ; t the two patterns are interchangeable, but Mark II. has a

• There is no necessity for a •4" length of mea led powder in this fuze, as themarking only comm ences at , i .e. , 20 on the fuze.

1._ The safety pin ia. made of oopper. Brass is employed in the B.L. B.L. plain and sensitive percussion fuzes for this purpose, and it is probably preferable,see p. 45.

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.•decided advantage as to safety. As before pointed out, Mark I.-9-second fuze m ay cause a blind shell when used with Shrapnel (see p.30). There is a difficulty in fixing these fuzes properly ; they aredirected to be screwed in by hand and not ham mered (see p. 65) . Nodoubt it would be dangerous to ham mer in Mark I., and it is contrary

to regulation to do so with either pattern. 5- seconds B.L. Fuze.— For shells with which this fuze is used see

table, p. 58). For construction and general arrangement, see cut.They are sim ilar to those of the 5-seconds M .L. Marks I. or IL, exceptas regards the arrangement of the head. As there is no windage, thefuze has to be ignited by a detonator. A cylinder, of an alloy• resemblinggun-m etal, screws into the head of the fuze ; this cylinder contains ahamm er, supported by a copper w ire, below the hamm er is a hol lowin the cylinder containing a detonating com position, viz., chlorate of potash, 6 parts ; fulminate of mercury, 4 plies ; sulphide of antimony,4 parts. A hole is bored through the cylinder for the passage of theflash. A copper safety pin passes through the head of the fuze betweenthe hamm er and the detonating composition, so that the fuze cannot beaccidentally fired, even if the suspending wire be accidentally sheared.

This pin is withdrawn by the braid just before placing the shell in theSun.

5-.eoondaB.L.fuse.§1984.

There are three escape holes, one of which is show n in the section, toallow of the escape of gas. These holes are protected by thin copper discsand papier mfiche wads, which are forced out by the gas when the fuzeis lighted ; quickm atch leads up to these holes. The exterior of thehead is woolded w ith copper wire, soldered over, to keep it from splittingwhen the detonator is being screwed iu.

• For details of alloy, eee p. 33 2.

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The ignition is produced by the hamm er setting back o n the shock of discharge, and thereby shearing the copper wire and falling on thedetonating composition ; the latter is thus exploded and the fuze ignited.

9 - seconds B. L. Fuze. — For shells with which this fuze is used , seetable, p. 58. The construction is identical with that of the 9-seconds-

M.L. fuze, Marks I. or II., except the arrangements in the head, whichare the same as tho se described above for the 5-seconds B .L. fuze. 20- seconds B.L. Fuze. — For shells with which th is fuze is used, see

table, p. 58. The construction is identical with that of the 20 -secondsM.L fuze, Ma rks I. or II., except the arrangem ents in the head, whichare the same as those described abo ve for the 5-seconds B.L. fuze.

For Ma rk I. of the 9 and 20-second B.L. fuzes, see §§ 873, 1417, andp. 38. If Mark I. 9-second fuze be used with Shrapn el shell, the kamp-tulicon disc should be first removed ; otherwise, as previously pointedout, the shell may be blind.

N.B.—All the B.L. fuzes are rather longer than the correspondingM.L. fuzes, owing to the room tak en up by the detonating arrangem ent.

Short Rule for getting the Length of F uze.

Divide the number of hundreds of yards in the range by 2, and add 1up to 1,00 0 yards, 2 up to 2,00 0 yards, and so o n for length of fuze in.tenths of inches ; this will be found nearly correct with rifled ordnance.Exam ple • to find length of fuze at 2,600 y ards for 16-pr. gun,

''+3=16.

Shrapn el require to be bored a little shorter.

Short Rule for getting Length of Fuze for Mortars.

Add 17 to the number of hundreds of yards in the range for thelength of fuze in tenths of inches, thus the fuze for 1,700 yards will be3".4.

It must be remem bered that all the lengths of fuze given by rules orby range tables must be taken as a pproximations only to be correctedby practice. As before pointed out (p. 27), the age of the fuze, the

height of the barom eter, and a variety of other causes affect the rate of burning. W hen blind shell occurs, a shorter fuze should be tried.

Rules for use of the various Fuzes for Rifled (guns. *

The following are general rules for the employment of time fuzes forrifled ordnanc e:

1st. The 5-seconds fuze is for use with Shrap nel shell for ranges up toabout 1,700 yards with R.M.L. guns, and to about 1,60 0 yardswith B.L. guns.

2nd. The 9-seconds fuze is used for Shrapnel, comm on, 7" and 7 -pr.double shell, and garrison segment shell. It is available forranges up to about 2,800 yards with R.B.L. guns, and up to-about 3,100 w ith R.M.L. guns.

3rd. The 20-seconds fuze is for garrison com mon shell and for garrison

segm ent shell at long ranges, and for the 7 -pr. double shell.It is not available for Shrapn el, because there are no po wderchannels to conduct the flame to the primer.

• This gives geseral rules only, for details, see table p . 68. It is to be rememberedthat time fusee are not used with the Woolwich guns in the L.S. ; and in the 8.8., only with Shrapnel ; and with comm on and double shell from the 7-inch gu n with s141bs. charge.

9-seconds B.L.fuze, Mark II.,§ 1999.

20-secondsR.L. fuze,Mark II.,§ 1999.

9 and 20seconds B.L.fuzes, Mark I.



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In all cases the `nature of the gun, whether B.L. or MIA, mast beconsidered. On an emergency, B.L. fuzes might be used with R.M.L.guns.

A R M S T R O N G "E." Ti FUZE.

Armstrong "E." Time Fuze.—

It is only used by the Navy with B.L. § 1907.segment shells, F.S. It was withdrawn from the Royal Artillery inJune, 1870.

It represents a large class of time fuzes employed by continentalnations with S hrapnel shell.*

The construction is com plicated, and its cost about double that of the Boxer B.L. time fuzee, but it has several important advantages,specially as a fuze for Shrapnel. It can be set to very sm all intervals,a point of the greatest importance with Shrapnel shell, it can bealtered again after setting, and it is open to inspection, so that theofficer or the No. 1 of a gun can see that it is correct, instead of depend-ing on those employed in preparing shells at the limber or in the shellTOM.

It is not necessary to give the various patterns which have beenintroduced, or to dwell on the various changes of m anufacture, as onlyone nature of fuze is now issued to the service, and m ay be know n by § 2178.the word " cap " stamped upon the base of the fuze. Various marksmay be found in c ombination with this word, as old fuzes are repairedby having cap composition substituted for the amorphous phosphorouscom position which did not stand exposure to climate and deterioratedby k eeping.t

The fuze being com plicated in its construction deman ds very carefulman ufacture, and in this respect compares unfavou rably with the Boxerfuze, as there are mo re sources of failure.

Many defects existed in the early patterns,t and so brought the fuzeinto disrepute. The chief faults are :-

(1.) The fuze occasion ally fired when c arried in the limb ers. Thiswas due to the pellet containing the detonating compositionbeing supported by lead feathers, which gave way under the

jolting motion of the limbers. This has been remedied byusing a cup-shaped support of thin brass, as shown below.(The cup was p roposed by C ol. Freeth, R.A.)

(2.) The fuze sometimes failed to ignite when the detonatingarrangement f ired. This was due to the hard surface of thefuze com position ; the flash from the pellet failed to light itwith certainty. This has been overcome by boring a small

* A full account of the fuses used by European nations up to 1871 will be fountin Recherches thiorirses et profitless our lee Feasts, par H. Romberg. Thegradual development of the Armstrong class of fuzes c an be traced there, starting fromthe Bormann and Breithaupt fuses, to those used by the Prussians, Austrians, andSwiss. There is also an interesting appendix to the a bove work, entitled, Posies' Prossimmes, m odification, proposies, par H. Romberg. Both works are publishedby H. Mersbach, Brussels .

t This composition con sisted of amorphous phosphorus (with 10 per cent. calcinedmag nesia) 8 g rs., chlorate of potash, 16 gre., ground glass, 6 gre. The deterioration was caused by the effect of moisture, which caused the phosphorous to oxidise at theexpense of the chlorate of potash, thereby injuring or destroying, according tocircumstances, the detonating cha racter of the composition.

2 Much information will be found in a book by Col. WraT, 0.B., BA., giving the"Changes of pattern and modifications in the Armstrong tune and F.S. percussionfusee since their introduction in 1860," printed at the D .G.O. Office, Woolwich, in1869 ; also see §i 90, 609, 1,294, 1,472, 2,178 2,496, Changes in War Stores.

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"E" timefuse,Mark §§ 1472, 1790,1791, 2178,2498.

hole in the ring of fuze composition dose to the channelwhich conducts the flash.

(8.) The fuze sometimes becam e unserviceable from the phospho rouscomposition deteriorating. This has been overcome, as pointedout before, by using cap composition.•

No dou bt a prejudice was created by the bad results obtained whenusing this fuze with segm ent shell, but these shell should be u sed witha percussion fuze ; no t ime fuze wil l g ive good results with segmentshell (see p. 148).

The following is a sho rt description of the fuze at present issued tothe Navy:—

Both body and nut of the last pattern (E. III.)' are made of gun-metal,and the gradu ations for length of fuze in inches and tenths are m arkedon the m etal rim instead of on paper, as in former patterns. The pellet

which is supported by a brass cup is filled with R.F.G. powder, securedby thin paper fastened on its base ; the detonator in the head con sists of § 2178. cap com position (fulminate of mercury, chlorate of potash, a nd sulphide

of antimony), instead of the amorph ous phosph orous composition whichdeteriorated in damp climates. In those lately mad e a disc of brass,-001" thick, covers the deton ating com position. The w ord cap " isstampe d on the base of the fuze.

The channel by which the flash from the pellet reaches the ring of fuze composition is enlarged in this pattern, and a strand of quickm atchis placed in it ; a little hole is bored m the rind of fuze com position to

iensure its lighting. The fuze composition i s pit mealed powder pressedinto a ring or groove wh ich runs round close to the exterior of the fuzebody ; this composition burns at the rate of 1 inch in;wo seconds, and ,owing to a metal stop, can only burn iu one direction, i.e., from left toright.

A leather washer and movable gun -metal collar cover the ring of composition. At one part of the collar a channel, primed with mealedpowder driven and pierced, and marked on the outside with an arrow,commu nicates with a groove round the neck of the fuze, which containsmealed powder; this groove is connected by a channel with the blowing

• An a ccount of an extended trial of the old pattern of "E." time fuze will befound in Extracts, Vol. VIII., p. 188.

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4chatab er, which is primed w ith mewled pow der, driven and pierced ; asmall brass disc closes the chamber.

The m ovable collar is kept in its place by a nut w hich screws on tothe neck . The body h as a sm all hole in the side to fit a projection inthe Armstrong key u sed in screwing in the fuze. See p. 65.

Stress must be la id on the importance of screwing the nut t ightlyhome when the fuze is adjusted, otherwise the washer will not betightly pressed down o n the ring of fuze com position, and a prematuremay O CCEIT.

On firing the gun , the brass cup is crushed in, the pellet strikes theneedle, which explodes the deton ating comp osition, the ring of fuze-composition is ignited by the flash and barns till it com es to the channelma rked by the arrow head, leading to the groove in the neck primedwith mea led • •wder, the flash is then instantaneously c onveyed intothe blowing c ber, and thence into the shell.

The changes recently introduced, particularly the cap compo sition,and the ensuring ignition by piercing a hole in the ring of fuzecom position, have greatly improved this fuze.

Divide number of hundreds of yards in range by 6 for length in

inches, thus for 1,200 ya rds, length of fuze = 2 inches.One in a waterproof bag placed in a cyl indrical t in box wrapped in

brown pa per, 72 boxes in a deal case, placed on the sides or heads, thebottom of each tin box is marked " top " to prevent it being placeddown wards. Since Jun e, 1875, the tin boxes containing " E." time fuzes,primed with cap composition, are stamped "cap," and the same wordis stencilled on the waterproof bag. Since July, 1875, in the case of repaired fuzes the date of repair will be labelled on the boxes con tainingt h e m .

An " F " t ime and percussion fuze was introduced in 186 7, but wasnot a su ccess, as the percussion action o ften failed. It was ordered inFebruary, 1869, to be regarded simply as a time fuze, and in June, 1869,th e manufacture was discontinued, the " E " time fuze, Mark III.,previously approved for India, being then broug ht in for general service.

Special Fuzee.

Hand Grenade Fuze. — Used with the 3-pr. or 6-pr. hand grenades. Theyare readily known from all other fuzes by their small diameter, absenceof paint, and by the head being secured only by a paper cap. Theycontain 1-5 inches of fuze com position, which burns 7.5 seconds; thecomp osition is unsupp orted at the base.*

No boring is required ; the fuze must be firmly fixed in the grenade,uncapped, and lighted by a portfire.

They are now rarely demanded. When men are using them theyshould be cautioned not to retain the grenade too long in their hands.

1,200 in .a whole metal-lined case.These fuzes in their general construction, preparation, and action,

resemble the common fuze. The figures, however, give the time of burning in seconds instead of half-seconds ; a pap er label is pasted abovethe row of f igures with the words " t ime of burning," and the figureshave " " " above them indicating second s. The fuzes are painted blue.Each natu re of parachute light has a special fuze.

* As the grenades are thrown by hand, support at the base is unneuessary.7,

Pr epar a t ion . ' '

Act i on .

Short rule forfinding length

of fuze.Issue.

§ 2751.

§2781.

§§ 1473, 1688,1720, 1790.

Hand grenadefuse.

Preparation.

Issue.

Fuses for

parachutelights.



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10-inch para-chute fuze.

8-inch pars-chute fuze.

5i-inch pars-ante fuze.

Fuze for life-saving rocket.

10-inch Parachute Fuze.—Has three inches of ordinary fuze compo-sition and burns 15 seconds. The first side hole is numbered 6 ,indicating 6 seconds ; the second row of side holes give the half-seconds, beginning at 6.5 ; the last hole is numbered 1 5. The fuze is.about four inches long.

8-inch Parachute Fuze.—Has 2 inches of slow burning com posit ion,which burns 18 secon ds. The m arking is peculiar, the first side hole isnum bered 7, indicating 7 seconds, the top side hole of the second rowis numb ered 715, the next hole in the first row is num bered 8.5, and so.on, the fuse reading to intervals of second, the last hole is marked13. The fuze is about three inches long."

5.i-inch Parachute Fuze.—Has 1.5 inches of slow burn ing compo sition,which burns 10 seconds. The first side hole is num bered 4, indicating4 second s; the succeeding holes are num bered 4.75, &c.; the last sidehole is numbered 10 . This fuze is about 24 inches long.l .

Fuze for life-eating rocket. See p. 282.The following are the limits of time of burning allowed in m anufac-

ture. These must not be confounded with the limits employed intesting fuzes at out-stations given in Instructions for Proof, p. 30 7.

Large mortar fuze • •SmallCommon KzeDiaphragm Shrapnel fuze . •5-seconds M.L. and B .L. fuze9 I t20 „Iland-grenade Fuze ..

8, , ,,

, , 54 ,, ,,

Time of burning.

30 to 32 seconds.15 to 16

13

91 to 10.34.8 to 5.24.8 to 5.29.7 to 10.3

19 .4 to 20. 6

7 .5 to 8

. 0

14.4 to 15 . 6

12 . 5 to 13 . 5

9.7 to 10.3

• •Parachute light, 10-inch fuze

The reason why n o minu s limits are allowed for the mortar fuzes isbecause the shells are fired with a low velocity and contain largecharges ; hence a fuze burning at all short is to be avoided, as pieces of the shell might fly back to the battery ; a m inus limit would evidentlybe most objectional in a hand-grenade fuze, so non e is allowed.

Manby's fuze.

* The 10 and 8-inch parachute fuzes may on any emergency be used with commonshells for S.B. guns.

t This fuse would not be used with S.B. common shell as its diameter is too small.

Mosby'. Fsze.—Is obsolete, as the Manby's shot has been superseded by the life-saving rocket. Their use was to give light so as to allow the course of the shot to beseen at night when firing over a wreck. They burned 121 seconds.

Digitized byGOOgle



45

CHAPTER V.-PERCUSSION FUZES.

GENERAL REMARKS.-PETTMAN L.S. AND G.S.-B.L. PLAIN, R.L. FUZES,

AND SENSITIVE FUZE.

Wo od, though suitable for time fuzes, cannot b e used for percussion Geneve

fuzes, where great nicety o f fit is necessary, and w here evert a trifling rma rss'alteration of form would prevent the fuze from acting.*

The m etal employed m ust not be liable to oxidise readily ; iron wasat first tried and proved to be quite unsuitable. The so-calledmetal, consisting of copper and tin, to which a little zinc hasaddedt (see p. 332), answers well for the body.t Copper wire hasbeen found suitable for suspending any part of the fuze which has to" set back " on the sho ck of the d ischarge, while brass wire, being lesssoft and m ore elastic, is suitable for safety pins.§

Lead answ ers well for checking rebound s, owing to its softness andlack of elasticity, but these qu alities render it unfit to be the su pportto the internal parts of a fuze, at least when it has to sustain theshock caused by the jolting motion of a limber ; it answers howeveras " feathers " or projections destined to be sheared on the shock of

discharge.When percussion fuzes are employed in rifled shells which strikepoint first, a very simple construction answers, but when shell maystrike in any accidental position, the problem is more difficult, as maybe exemp lified by the construction of the obsolete Moorsom fuze, whichhad no less than 3 hamm ers and 5 patches of detonating composition.The difficulty has been successfully met in the Pettman fuzes.

Percussion fuzes are em ployed for two distinct purposes ; they are

• Freoburn's concussion fuze was made of wood. The principle is simple andingenious. The fuze contains a central channel, the lower portion of which is driven with fuze com position, the upper with m ealed powder. Three holes closed withthree conical plugs with the large p art of the cone towards the interior of the fuzelead into the portion of the fuse driven with m ealed powder. On firing, the conical plugs are sup ported by the m ealed powder, this burns away rapidly, and when the

shell strikes the object the plugs being unsupported fall into the fuze, the flamefrom the fuze composition passes through the holes and explodes the shell. SeeExtracts, Vol. VIII, pp. 86, 163, 348.

t Adding a little zinc or lead renders the m etal easier to turn.I It is essential that the bodies should be strong, as otherwise the fuse will fad

with even moderately heavy charges. Hence the introduction of Mark IL R.L. percussion fuze. Se e p. 55.

§ Wire is n ot suitable when a " pellet " is desired to set back on the shock of .discharge, and to move forward again on striking an obstacle, as the broken ends of the wire are liable to form burrs and check the action.

, , I

I::1



46

used in shells intended exclusively to act against solid obstacles, suchas earthworks,brick, or mo derately thin stone walls, or wooden ships;and they are also used in shells employed a gainst troops in the field, aswell as in shells directed against buildings and m aterial generally.

For the first purpose it is desirable that the fuze should on ly act ondirect impact, and a very instantaneous action is not required. It will

be seen (p. 48) that the Pettman G.S. percussion fuze is speciallydesigned to act only on direct imp act.For the second purpose, when used a gainst troops in the open, it is

necessary that the fuze should act on graze, and that it should actalmost instantaneously, as otherwise the shell has time to rise to aconsiderable height before bursting, and thus its effect against troopsis diminished. Such an action is secured in the R.L. and B .L. plainpercussion fuzes and in the Sensitive fuze. This nature of fuze isabsolutely rryy to develope the effect of segment shell when usedagainst troops in t e field, and good resu lts have been obtained fromShrapnel when using such a fuze at moderate ranges.

Safety pins are used in the fuzes w hich act on graze. They serve toprotect the " feathers " in the fuze by taking the shock caused by the

jolting motion of the limbers. The " feathers " only come into usewhen the safety pin is withdrawn, guarding against risk while theshell is ramm ed home.

It is important to employ a detonating composition which keepswell ; the earlier percussion fuzes frequently failed in this respect_ Experiencehas proved that cap compo sition (p. 320), properly pressedand varnished, resists climate well. The most trying climate is onewhere great changes of temperature are to be met with in combinationwith hot damp seasons ; parts of India are very trying in this way.The changes o f temperature are likely to open the joints of the fuze byalternate expansion and contraction, while the warm damp air is Bure-ts) penetrate it, if it f i nd s the least opening Even in such clim ates theordinary percussion caps are foun d to keep w ell ; this is due probablymore to the mechanical condition of the composition, than to anyspeciality in the com position itself. A very heavy pressure is appliedto the compo sition when placed in the cap, thus forming a hard po lished

surface not liable to absorb m oisture : in addition the com position isprotected by varnish.

In a l l fuzes where pressure can be applied to the detonating com-position this system is carried out, but it canno t be done in all cases,and w here it is im possible, the greatest care must be taken to c losethe fuze hermetically. This is illustrated in the construction of thePettman G.S. fuze.

All percussion fuzes in the service at present (except the B .L. plain,which fits inside the shell) , are tapped w ith a screw thread to fit intothe conical fuze ho le of the shells* A fuze having its screwed portionconical can be screwed hom e mu ch m ore rapidly than wh en it is of acylindrical form, as the fuze will enter some distance into the conicalfuze hole before the screw bites. There is no n ecessity for a shoulder,as a conical screw can not be screwed too far hom e.

Percussion fuzes are useful in the absence of range finders when firingtrial shell, It is difficult when time fuzes are used to judge exactlywhether the shells are bursting under or beyon d the object, but when

• A number of obsolete fuzes, such as the Moorsam, 7* and 20-seconds metalfazes, pillar fuses, and Pettman S.8. fuze, may readily be distinguished by theirbeing tapped to fit the cylindrical MOOTS= gaug e.



47

the shells are burst on the groun d it is easy to determine on which sideof the object they are bursting.

Percussion fuzes are useful when firing at artillery where a localaction is desirable ; they are less effective than time fuzes against an open formation of troops.

A great advantage of this class of fuze is that they require nopreparation, beyond withdrawing the safety pin in those fuzes whichact on graze. The safety pin of the sensitive fuze is not withdrawn,but the fuze is uncapped.

For the Navy , a proportion of the shell are issued filled, and fuzedwith the Pettman G.S. fuze. Shell thus fuzed are very safe, and notl ikely to be injured by an accidental explosion in their neighbourhood.See p. 132.

The following brief account of the percussion fuzes in th e service willbe sufficient, in conn ection with the d rawings, to explain their action :—

Pittman Percussion Fuze, L.S.

Penman Percussion Fuze, L.S., used with comm on shel l of comm ongauge. The fuze hole m ust be tapped through out to receive this fuze;

this is indicated by a cross cut on the plug.*The body of the fuze is made of gun -metal ; the ball, cone plug, and

steady plug, of a harder alloy to strengthen them ; the remaining partsare gun-metal, except the lead cup.

The section shows the construction.

Pcttman percussion,

fuze, L.S..§ 414.

A. Body.B. Top Plug.c. Steady Plug.n. Detonating B all. x. Cone P lug.F. Lead Cup.G. Bottom Plug.

A strand of quiokm atch closes the Ire hole in the bottom plug.No pr!paration is wa nting with this fuze, which explodes the shell on

its striking a hard body, such as a wooden ship, walls, &c. It is notintended to act on graze.

The ball is the only part of the construction which is not quiteexplained by the sketch ; it is roughened by vertical grooves and has ahorizontal groove as well ; it is coated with a detonating com positioncomposed of chlorate of potash, 6 oz.; milli& of antimony, 6 oz.•,sulphur sublimed, I oz.; mealed powd er, It oz .; m ade into paste w ithmethylated spirit and shellac. Varnished gut is tied over it, and acover of varnished silk over that ; these covers both keep off dam p andprevent premature explosion.

On firing, the shock of discharge crushes up the lead cup , the ball, Action,

cone plug, and steady plug setting back • the sketch shows how the lead

cup dovetail(' on to the cone p lug and bottom plug, preventing rebound ;the steady plug prevents the ba ll touching the sides as it sets back, andthe irregular motion o f the shell in the air causes it to disengag e fromthe ball. On the shell striking the ob ject, the ball, now unsup ported, isdashed violently against the side of the body, explodes the detonating

• The fuze is fixed in the shell by the key, fuze, and plug, GM., see pp..116,•39.



48

Issue.

Proof.

rcttman per-. . eussion fuze,0.8., Mark I.§ 1235.

Figs. 1, 21.

Top plug.Figs. 2, 3.

com position and fires the shell, the flash passing through holes in thecone and bottom plugs. The hole in the latter has a thin paper discover it.

These fuzes are packed by fives in tin cylinders.This fuze was introdu ced for garrison service ; it is not suitable for

field gun s as it does not act with certainty on graze.5 per cent. of the different parts are most carefully gauged beforebeing put together; samples of the metals are selected and subm itted tothe Chem ist, War Depa rtment, for analysis. After the fuzes are finished15 per 1,000 are selected for examination and proof. The whole of these are carefully ranged and exam ined.

10 are dropped in a 3 2-pr. com mon shel l 20 feet on an iron block,in any accidental position. These should not explode. Three of thedropped fuzes are opened and the balls taken out and a weight of 7 ounces allowed to fall upon them from a height of 22 inches. Theseshould fire.•

The 5 rem aining fuzes are fired at Shoeburyness from a 32 -pr. gun,com m on shell, 3 with 10-lb. charges at about 8° elevation to ricocheton w ater. The object of this proof is rather to test the fuzes un der ahigh charge than to determine w hether or not they explode on strikingwater. As a general rule they do not explode, but they are notspecially constructed to stand such a test.

The other 2 are fired w ith a 4-lb. charge from the sam e gun, at anoak butt, 200 yards. These should explode.

Pettman Percussion Fuze, G.S., Mark I.

This fuze is arranged so as to act equally well from a S.B., from aB.L., or R.M.L. gun.

For shells with which this fuze is used, see table, p. 58.It is specially designed so a s to act on impact, not o n graze ; it will

not explode on a shell passing through a wave, but will explode on theshell striking a woo den ship.

Its construction is shown in the plate. Page 352.The body and top p lug are made of gun-metal, the cone plug,

detonating ball, and steady plug are also made o f gun-metal, but of aharder alloy to prevent them from altering their shape ; the plain ballis made of brass, and the suspending wire is made of copper.

The body is conical, tapped throughout with a screw, to screw intothe G.S. gauge fuze hole, it is about •2" thick, a strong case beingessential to resist the shock of a heavy charge. It is slightly hollowedout in the cen tre to allow sufficient play to the detonating ba ll, andis also hollowed out at the base to allow the lead cup to dovetail intothe recess when it is crushed up. There are two slots cut in the topof the body to allow the fuze to b e screwed into the shell, it is tappedat the top to receive the top plug. There is a hole in the centre of thebase which serves to allow the cone plug to set back .

The top plug is a small disc having two holes in the upper part toenable it to be screwed into the fuze, and a cup-shaped recess in its

lower part, into which the plain ball fits ; it is tapped with a screwthread to fit the body.

The plain ball is a sm all solid ball, turned from brass wire.

The steady plug is a disc, recessed at the top and roughed to receive

• This proof is quite distinct from that used by fire masters at outstations,s e e p . 8 0 8 .

Digitized byGOOSIC

Plain ball.Fig. 4.

liteady p lug.Figs. 5, 6.



49

qt ring of detonating com position, and having a cup in the centre toreceive the plain ball ; three fire holes are pierce' through it to allowthe flash to pass down . The bottom of the central hole is enlarged toreceive the projection of the detonating ball. A detonating com position(see p. 320) is pressed into the recess a nd is covered over by a thin

.copper washer. The detonating ball is roughed b y a num ber of vertical grooves and

has a deep h orizontal groove near the centre, these grooves serve toretain the com position with wh ich the ball is coated (see p. 320), andalso render ignition certain when the ball strikes against the body. At-the top of the ball is a cylindrical projection wh ich fits into the steadyplug, and at the bottom is a smaller rounded off projection which fitsthe cone plug. Over the composition two thin copper hemispheres areplaced and un ited by a piece of shellaced pape r, the ball is furtherprotected by covers of varnished gut and silk.

The object of the copper hem ispheres and of the copper washer overthe steady plug is to bring the sensitiveness of the com position withinsuch limits that the sh ock of grazing will not explode it, wh ile the.shock of direct impact against a solid body will make it act.

The con e plug is so called becau se it has a con ical form in thePettma n L.S. fuze. It is pierced by th ree fire holes, the centra l one

'being slightly enlarged to su pport the detonating b all, the bottom of the plug contains a cham ber which is filled with m ealed powde r, drivenand p ierced like a tube, it is recessed near the top o f the cylindricalpart to allow the lead cu p to dovetail on to it, pierced near th e basefor the suspending wire, and closed at the base by a sm all cardboarddisc.

The lead cup is a hollow cylinder, having a flange on the head to fitthe recess on the cone plug.

When the fuze ha s been put togethe r in a perfectly dry state, thetop plug,laaving its edges coated w ith a waterproof cement,* is screwedin and al lowed to stand un ti l the cem ent sets. The slot holes in thehead of the fuze are then carefully filled with cement, the hole in the

'base is closed by a cardboard disc, and finally the top and bottom of the fuze are coated with cement. These cementing operations secureth e fuze from dam p, their importance will be seen further on. Fuzesthus secured have been found to resist water when placed in it for somehours.

A label is attached to the top of the fuze, giving the Mark, num berof thousand and date of manu facture; if the fuze has been secured orre-primed, the letters t S. or R . and da te of the operation will be foundon the label. P. on the label shows that the fuze has b een packedin tin cylinders.

The Mark I. fuzes as above described were found to deteriorate to avery serious extent in store, especially in hot moist climates. Num erouscomplaints were received from foreign stations, and for a time it was-hoped that when secured from damp , re-primed, and k ept in hermetically

sealed cylinders that the evil would b e obviated. This result, however,was not attained, and even under these circumstances they d eteriorated

Figs. 16, 17.

Detonatingball.Figs. 7, 8, 11.

Figs. 9, 10.

Cone plug.Figs. 12, 13.

Figs. 18, 19.

Lead cup.Figs. 14, 16.

Securing oroementingPettman G.S.fuze.§ 1719.

Fig. 20.

Pettman G.8.fuse, Mark II.

• Venetian red, Stockholm tar, she llac, and methylated spirit,.t Pettman G.S. Pus is, Mark I., which have not the letters S. or It., and a r e of § mat

manufacture previous to 434th thousand, are not to be considered sena:cable ; and § 2359.,are to be returned to Woolwich for exchan ge unless in shel l on board sh ip.

Few, if any, of these are now likely to be met with, u the order above came outin October, 1872.



50

§ 3200.

Proof.

Action.

to a very large extent.* At the same time the Pittman L.S. fuzes.which were packed either singly iu waterproof bags or simply usbrown paper, and kept loose in a deal box, seldom failed to satisfy theproof.l. This made it apparent that there was some defect inherent inthe fuze itself. It turned out, as the m ost probable cause, that thesublimed sulphur t used in the detonating composition was liable tocontain free acid. The composition being on the gun-metal ball, and'covered by the copper hemispheres, was injuriously acted upon inconsequence pa rtly by chemical and partly by the setting up of galvanicaction. Hence Mark II. Pettman G .S. fuze has been introduced.

It differs from M ark I. as follows : The detonating ball with thecomposition on it is covered first with gut, then come two thicknessesof thin silk, then the copper hemispheres, then another layer of gut,and lastly three thicknesses of silk. Each layer of silk and gut isvarnished. This entails slight modifications in the ball, so as to allowof the extra thickness of pr6tection, and in the copper hemispheres.The copper washer on the steady plug is also lacquered.

Mark I. is easily converted into M ark IL. and w ill probably be entirelyused up for this purpose.

per cent. of parts gangel, samples of metal subm itted for chemical

analysis, &c.15 per 1,0(0 of these fuzes are selected for proof, 10 of these are

placed in an iron block and dropped a height of 20 feet on to iron, theyshould not tire on falling, but may do so when the fuze rebounds andfalls a second time, as the first fall puts the fuze in action. This testproves that the interior parts of the fuze are properly arranged, as if the balls were out of position the fuze would fire on the first fall.3 fuzes are fired from a 7-inch R.M .L. gun, charge 22 lbs., to r icochet onwater ; these should not fire.§ 2 are fired in a 40-pr. B.L. gun witha small charge, 4 lbs., against an oak butt, or against sand bags 200'yards off ; these should fire.

The very ingenious arrangem ent of this fuze is necessary to meet thedifficulty of getting a fuze to act with rifled guns of both nature; andalso smooth bores. For rifled guns only, a much simpler arrangement

answers.(1.) Suppose a shell fired out of a M.L. gun, the steady plug, ball,

and cone plug set back on shock of firing, the suspending wire isbroken, the lead cup prevents rebound, and the stem of the cone plugprotrudes through the base of the fuze, the detonating ball beingreleased from its pivots by the slight wobble of the shell ; on striking,the action will be the same as in the L.S. fuze, the flash finding exit,through the boles in the cone plug, to the priming, and thence to thepowder in the shell.

(2.) When fired from a B.L. gun the steady plug may not disengage,owing to the steadiness of the flight of these shells, and in this casethe detonating ball w ill not act ; the plain ball is released by the steady

Oa the average over 30 per sent. failed under drensaster's peva at ea tpstationa

In the cause of n early four years, as &vomiter at Bcrmu ds, I Lever knew aL.S. fuze to fail at proof, while on the other ha nd the 0.3., which had be en com-

ely a very short time in stove, even if left in the hernietieally sealed eylindere,uently deteriorated so much that the detonating composition might be scraped

off the bell with • knife, and hamm ered on iron without detonating ; and this when30 signs of damp were visible.

(hound distilled sulphur will be n eed in future.§ This proof is quite distinct from Act used by &twitter at outitatioes.

E lm p. We.



51

plug setting back , and is caused by the centrifugal force to spin roundthe circumference of the body over the ring of detonating composition.On shock of striking the object, the ring is dashed against the plainball and detona tes, exploding the shell through the fire holes.

These fuzes are packed b y five in tin cylinders.This fuze being specially designed for firing o ver water is issued to

sea fronts of fortifications and to the Roy al Navy.

It is to be remarked that it is impossible to protect the compositionon the detonating ball by pressure and varnish in the same way as canbe done in a cap. It was early found that the dam p affected these fazes §§ 1612,164t _

and the first remedy w as to protect them by unscrewing the top plug,luting it with red lead m oistened with shellac varnish, screwing it inagain, and coa ting the top with the biting; this was to be don e at out-stations as well as at Woolwich.* § 1 7 4 3 .

Experience has shown the Pettman G.S. fuze to be very safe fromprematures.

Both the Pettman fuzes are designed to act on direct impact, butthe L.S. may occasionally act ou graze (see proof, pp. 48, 50), the G.S.on the other hand requires direct impact. The proof shows with whatnicety the sensitiveness of this fuze has been brought within the desiredli mits, as it explodes when fired with a reduced charge from a B.L. gunagainst wood, and do es not explode on striking water when fired with abattering charge from a 7-inch R.M.L. gun.

W e now com e to the fuzes which act on graze. The smaller the chargethe more difficult it is to ensure the action of the fuze. The fuzes aboutto be described act very well in the ordinary field guns, such as the 9-pr.and 16 -pr. R.M.L. and in the Arm strong B.L. field guns, the difficultyoccurs in such a gun as the 7•pr. R.M.L. when using a 6-oz. or 8-oz.

charge t where the velocity is too slow to ensure sufficient shock beinggiven on discharge to shear off the feathers. Quickness of action isessential with these fuzes, as the effect of a burst on graze is lost if theshell has time to rise to any height before bursting.

A short range is the m ost trying to the fuse, as when the trajectory isflat the velocity of the shell is but little checked by gra zing ; these fuzeshave however been found to act well at 400 yards and even at shorterranges. The softer the ground the greater the chance of failure, butour present experience is that these fuzes may be depend ed on over all

• At some stations the fuzes were found to be carelessly put together, so that thefuse was in a most dangerous condition, the detonating hall being loose inside. Allfuzes so repaired at out-stations were re-called. Should any still exist they may beknown by the date of repair being masked en them is s t amo s e r i p t . They are to belooked upon as dan gerous, and if in Mail with an unloadin g hole, tam bursting chargeia to be drowned. If the shill haw no unloading hole it is to be thrown into deep water.

t A letter from the Supe rintendent of Isperiments, Shoeburyness , states that66 common shell hare been fired from the?-pr. R.M.L. steel n, 6 oz. chew N.Growan-, R.L. ' fine, Mark 1. • 46 sated y, 4 en mesed grace,and were ark IL sate -

wo r s e , 6 at of 20 tried at proof were bbod.

A.C. 1 8 7 0 ,Cl.

16.

A.C. 1869,Cl. 143.

•u§ 2 3 5 9 .

D 2



5 2

natures of ground.' It is also satisfactory to find that preinatures areof very rare occurrence.

The fuze introduced in 186 2 closely resembles the present B.L. plainpercussion fuze in its arrangements, but the latter has two importantadvantages, viz. , cap com position, which, as before pointed out, resistsdam p, and a safety pin.

B.L. Plain Percussion Fuze.t

Used with field service B.L. common and segment shell. This isa modification of the Armstrong C. percussion, the improvement con-sisting in using cap comp osition pressed and varnished, as in gun caps,which experience has shown to stand dam p climates well.

The body and top are made of gun-metal, and the body has a rimprojecting at the top which ensu res the fuze being placed in the correctposition in the shell . In the centre of the top, on the inside, is fixed asteel needle, point down ; the top is pierced with four holes to allow of the action of the Arm strong E. t ime fuze, wh ich is still used in the Navyin conjunction with the B.L. plain fuze. A washer of thin sheet brasscloses these holes (it is blown in by the action of the time fuze). Thebody is pierced with two holes for the safety pin.

-- - 10i-

Z..

N.B.—The cut represents an earlier pattern converted. The presentpattern has the bottom screwed into the body.

• See Extracts, VoL X, p. 351.1 6 , 5 8 4

A letter in the Royal Laboratory, 15 , gives an account of a trial of the R.L.5

percussion fuse, Mark I., from the 9-pr. R.M.L. gun. It states that the fuze acted well on all natures of ground an d water at ranges from 825 to 2,250 yards ; 138 outof 141 burst on first graze. On boggy ground 102 burst first graze out of 108,rang es 600 to 1,500 yards. On sa nds 137 out of 143 burst on first graze, rang e 800to 1,800 yard.. This pra ctice was carriel on us ing the h ollow headed ram mer (n ow obsolete) and to this cause three premature, which occurred during the practice were attributed ; this ramm er used to grip the fuse, a nd so cause it to come loose inramming home.

This fuse was known as the "C. Cap" percussion fuse, but the nomenclature was altered to " B.L. plain " by § 2620.

By § 2029 a number of obsolete fuses were called in to be converted to theB.L. plain percussion fuze. They are easily known, as none of them h ave a safety pin with braid attached to it. When converted " Cap " is stamped on them. By

2761 the date of repair is to be labelled on the boxes. A " C." percussion screw fuse, which fitted the Armstrong F.S. gauge, is also

obsolete.For details of the various patterns of these fuses, from the introduction in 1860 of

Armstrong's original " Metal Concussion Fuse," see Colonel Wray's pamphlet, referredto in foot-note p. 41.

B . L. plain per-r uss ion fuze.§§ 1983, 2292,2620.

Vonstract ion.



r3

The guard is made o f gun-metal, and is pierced with two holes for Guard.th e safety pin • it fits inside next the top, and is recessed inside toreceive the head of the pellet ; there is a slight undercut at the top of the recess into which the pellet expands when the guard sets back.

The pellet is cast of equal parts of lead and tin ; it is hollowed out pellet.and receives in its .top the copper cap , which is primed w ith . ..ap com-position (fulminate of mercury, sulphide of antimony, and chlorate of potash), pressed' and varnished in the same way as in gun caps. Thecomposition is further protected by a very thin disc of brasst ; thishas been found necessary to prevent premature explosions; a disc of paper coated with shellac is stuck on the top of the pellet covering thecap. Cap..

The cap is pierced with three small holes, arranged in a triangularform round the centre ; these holes allow the flash to pass down to thelower part of the pellet, which is filled with a pellet of pressed powderpierfr.d like a tube and roughen ed so as to ensu re ignition.

On the exterior of the pellet are four feathers or flanges, and belowthe pellet a disc of paper is placed to prevent its adhering to the bottomof the fuze.

The bottom consists of a gun-metal disc which screws into the base Bottom. ,of the fuze; in the centre is a sm all hole which contains pressed pow derdriven and pierced as usual. This hole is closed on the exterior by athin brass disc.

The safety pin is ma de of twisted brass wire, and has a piece of braid Safety pin.attached to it to enable it to be withdrawn readily ; a little beeswaxis applied to seal the hole, and the braid is secured by a paper stripshellaced round the fuze.

Since 12/71 these fuzes have been painted with a black varnish § 2169.similar to that used with friction tubes in order to exclude damp asmu ch as possible.

Remove the safety pin and drop the fuze into the shell, rim to the Preparation.front ; replace the plug in the shell , except for naval service, when theE. time fuze is used.

When the safety pin is removed, the guard is supported by the Action.feathers of the pellet. On the shock of discharge the guard sets back,shearing off the feathers, and its shoulder is jamm ed iuto the undercutin the interior surface of the guard. When the shell strikes an opposingobject, or grazes, the pellet and guard fly forward as one mass, thecap comes violently against the needle and is thereby fired. The flashis taken up by the powder pellet, the brass disc at the bottom is blownout, and the bursting charge exploded.

This fuze may be depended on to act on graze even on wet boggy ground or on water, and will act at 400 yards where case ceases to beeffective. Before the addition of the safety pin the feathers of thepellet were found apt to give way under the jolting to which the fuzewas exposed in limber boxes; but now the fuze is quite safe, as the pintakes the part of the lead feathers, which are only called into play w hen

the pin is withdrawn.In tin cylindrical box, holding t*o fuzes, each fuze in waterproof Issue.

bag, 80 tin boxes, or 160 fuzes in a deal packing case. These fuzes §2217

.

will be issued in tin cylinders (5 in each) when the present store of cylinders is used up.

• The pressure is 600 lbs. on the area of the oap.'001" thick.

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11966. For field service 20 fuzes are ca rried on their sides in a tin box fittedto receive them, and carried in the centre limber box.

Fu:e, Percussion, R.L., Mark

f§ 2101,2620. Used w ith R.M.L. field service 7-pr. and 9-pr. comm on and Shrapnel• shell. This fuze exactly resembles the B.L. percussion fuze in its

internal arrangements. The bod y is of gun-metal ; both body an d topare cast in one piece, the bottom is screwed in, a squ are hole in thehead fits the G.S. key by which it is screwed into the shell. This fazefits the G.S. gauge.*

Preparlitit.:?.

Action.

The safety pin is a plain brass wire. Through the loop at one endpasses a brass wire ring which fits round the fuze in a recess cut forthe purpose in the 'uppe r surface of the shoulder. This ring has a piec eof braid attached to it, and the latter is kept in its place by a slip of paper pasted over it. The pin is not to be withdrawn until the shell is

placed in the gun.

When the safety pin is withdrawn, the hole through which it passed,if left open, would probably ad mit of the passage of the flash from thedischarge of the gun into the interior of the fuze, and so a prematureburst would take place. To guard against this a small lead pellet

slides freely in a recess cu t in the head an d closed by a thin brass thee,soldered on flash with the top of the fuze. When the sh ell is ramm edhom e the pellet sets back and so closes the safety pin hole.

See p. 66.

As described above for the B.L. plain fuze.

This fuze of course acts on graze in the same way as the B.L.p e r c u s s i o n . t

These fuzes resist dam p well ; out of 48 which had been wetted in acentre l im ber box only two fa i led, one from the cap being dam p, theother from the guard wo rking stifly.

* A leather collar used to be issued on the fuze un der the shoulder, but is now

discont inued as i t is an advantage to screw the fuze home as far as poss i ll e .t The action of this fuse from the 7-re. is uncertain, a considerable surobdr atblinds here oecurred.—Execaete, Vol. IX, p. 26.

It acts very well from the 9-pr. B.M.L.—Extracts, Vol. IX, pp. 67,119.The lowest charge that will cause it to act with certainty from the 9-pr. appears to

bo 10 oz.—Extracts, Vol. IX, p. 120.Trials were made as to whether the fuze would act without removing t h e nfeq

pin, several blinds occurred when the safety pin was left in.,--Extracts, Vol. 1X, p. 297.

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55

Five fuzes in a tin cylinder, each fuze wrapped in brown paper, and Issue.hsix cylinders packed in a deal case. § § 2201, 2328

For field service 16 fuzes are carried on their sides in a tin box forthe 9- pr., and 12 fuzes for the 7 -pr.

FUZE, PERCUSSION, R.L., MARK II..

For shells with which this fuze is used, see table p. 58.•

It can be used with common, segment, or Shrapnel shells, and will.act either on graze or impact.

It is tapped with a screw thread to fit the G.S. gauge of fuze hole.

Its construction is given in the p late, page 353.

This fuze has been introduced because the R.L. fuze, Mark I., wasfound to fail when fired with heavy charges, and differs from it itt thefollowing particulars:—

1st. The pellet and gu ard, vide plate, are sma ller in diameter, to adm itof greater thickness in the side of the fuze, and of a deeper screw

thread at the bottom, thereby giving the base greater power to support. t he weight of the pellet and guard on the shock of discharge.t

2nd. The pellet has no powder pressed into it, and there is anincreased quantity of detonating composition in the cap at the top of he pellet. The fuze is thus ma de quicker and mo re certain in its

.action.

3rd. The safety pin (of double twisted wire) passes through the head-of the fuze, and is kept in its place by the two ends being opened outslightly, so as to bind them selves in a conical cup, as shown in thedrawing. A thin disc of brass is then fitted in over the ends, andsoldered over to keep the fuze w ater-tight. The bead o f the safetypia is fitted with a loop of string, by which it is withdrawn . There isno brass ring or recess round the head of the fuze.

See page 66. The action is the same as in the B.L. and Mark I. fuzes, except that

t here is no pow der to ignite in the pellet, the flash from the cap goingdirect to the bursting charge.

As for Mark I. fuze.

Fuzes of Mark I. are only suitable for use with 7-pr. and 9-pr. guns;but for these natures they are as efficient as the Mark II. fuzes. Allissues for these two natures of guns will therefore be taken from the

-existing store of Mark I. fazes un til it is used u p.

The R.L. percussion fuze Mark II., has acted w ell from the 9-pr.,16-pr., 40-pr., 64-pr., and 80-pr. R.M.L. guns, and also from the 40-pr.

§ 2621.

Prepare( ion. - Action.

Issue.

• This fuze will reph see Mark I. for the 7 and 9-prs. when the protect stock of the § 2621.latter is toed up.1). N. 0., 18/4/74, reports that R.L. fuze, Marks L and II., answer equ ally when

fired in 7-pr. comm on and Shrapn el shell, 8-oz. charge. With the double shell, 4-oz.charge, .18 Mark I. out of 14 were blind, and of 14 Mark II. all were Wind. Thisshows tha t the 4-oz. a does not set the flue in action. Extracts, XII., p . 169.

t The thickness of the knimi disc, which closes the ilrehole in the batten, has beenreduced in those made since N ovember, 1878. The safety pia hole used tote catered

with beeswax , and the bottom of the fuze painted, but in reeent m anuisdu re these'operations are discontinued.

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5 G

Proof of B.L. plain and R.L. percussionfuzee, MarksI. and H.

Sensitive fuze.§ 3221.

B.L. gun ; if it was desired to use seg men t shell against troops in thenfield, this fuze would be invaluable.•

15 out of ea ch 1,000 are selected, the " feathers " are cut off 10 of them, and the fuze dropped head duw n about four inches in an iron•block ; these sho uld fire. The remaining 5 are f ired, the B.L. plainfrom 9 or 12-pr. B.L. gun, the R.L. from various R.M.L. guns up to the

80-pr., to see that they act on graze.tSensitive Frae, Marl. I.

A sensitive fuze has been approved for use with 7-pr. R.M.L. guns,and 8 " and 6"•3 R.M.L. howitzers. In general principle it resembles-the P russian percussion fuze.

E L E V A T I O N .

SAFETY PIN. SECTION ON A B WITH PIN REMOTED..

• See Extracts, Vol. XI, p. 67.The Sup erintendent R.L. states the trials of the E.L. percussion fuze, Mark IL,

hare been very satisfactory, that there appears to be no liability to premature-explosions, that the fuze acts with at least as much certainty as any other percussionfuze yet tried under similar conditions, and that the rapidity of action is better thanany yet tried.—Extracts, VoL XI, p. 134.

Experiments h ave been carried out to ascertain whether this fuze would set when,

used in connection with the lowest charge fired from the 8-inch R.M.L. howitzer, itfailed to act when fired with 5 lb. or 6 lb. charge s at an elevation of 10°, but acted

with charges of 71be. and over. The in itial velocity is probably too slow to cause tin-" guard " to set back when the sma ll charges are used. A trial at Shoeburynees (January, 1874) showed that the R.L. Mark II. fuze

acted with the 7-inch B. L. gun ; 25 were fired, 23 burst first graze, an d two burstsecond graze. It is obviously necessary to take out the safety pin before placing theshell in the bore when using the R.L. fuzes with B.L. guns.

The lowest charges which make the R.L. faze Mark II. act in the 40-pr. and64-pr. R.M.L. guns are 2f lbs. and 3* lbs. respectively.

t For Amm eter's proof, see p. 306.

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S E C T I O N .



57

It is designed so as to be equa lly efficient with very low charges andwith the highest charges used with the above pieces.

The fuze consists of (a) body ; (b) ham mer or pellet ; (c) steel needle; Construct iori_

(d) t h i m b l e ; (e) detonating cap ; (f) safety pin ; (g) outside primer of quickmatch, and (h) band. The body, hammer and cap are made of

gun-metal, and so is the bottom plug which has a fire-hole closed witha thin brass disc spun over.The hammer tapers slightly from top to bottom to allow it to move

freely forward on impact of the shell. A thin steel plate, the centreportion of w hich'forms the nee dle, is fitted as shown in the cut, into aslot in the top of the hamm er, and a hole bored through the centre of the latter allows the flash from the deton ator to pass on bo th sides of the steel plate and down into the shell.

The thimble is a thin brass cylinder, flanged at the bottom, andencloses the hammer. It allows the latter to move freely forward, and, going with it, prevents the hamm er from being imped ed by dirt, &c.,which m ight otherwise enter through the safety pin hole on graze ori mpact on earth, &c.

The detonating cap is screwed into the head of the fuze and secured

by a small side "stop screw." It contains about 71 grains of pressedmealed powder covered with a perforated copper disc. Below this ispressed 3+ grains of c ap com position, which is covered with varnished finewhite paper and a thin brass disc ; the latter has a hole -1" in diam eterin the centre to allow the needle to pa ss through to fire the composition.

The use of the m eal powder is to ensure the production of a sufficientquantity of flame to comm unicate with the bursting charge.

The sa fety pin is of brass wire (No. 15 B.W.G.) screwed to a heavyhead of gun-metal, as shown in the cut. It is secured by a strand of six-thread quickm atch, fastened by silk thread and coated with m ealpowder priming. The w hole is covered with a tape and copper band,like that used with wooden time fuzes for R.M.L.O. The safety pinfits easily through one w all of the body and into a recess in the oppositewall.•

The fuze is " uncapped " by removing the tape and copper band. preparation,

This is not to be don e till the shell has been placed in the bore.The flash of discharge burns up the quickmatch.' The safety pin,

Action.now free to move, is whirled out by the centrifugal force due to therotation of the shell. On impa ct or graze the ham mer and thimble flyforward and the needle point enters the cap. The flash passes downthe pellet, blows ou t the thin brass disc wh ich closes the base of thebottom plug, and so fires the shell.

Five fuzes in a tin cy linder. Six cylinders in a deal box. Issue.

* Gun-cotton loosely twisted will very possibly be shortly substituted for quick-match.

british time and percussion fuzes

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