belt sander1

7/28/2019 Belt Sander1

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Build Your Own

BELT SANDERThis wood-surfacing "smoothie" has two guide fences

for end or side finishing at any angleBy R ALPH G. HENDRICKSON

Sander base is adaptable

for mounting on various

power machines or on own

stand for direct V-pulley

motor operation. Slight ad-

justment of turnbuckles on

side rails controls belt ten-

sion, helps keep belt

centered on pulleys.

ANDING of a pro-fessional calibercomes easy with a

6-in. belt sander youcan make out of a fewpieces of stock lumberfrom your local yard.

If your home work-shop is like ours,chances are you canduplicate most of theunit we built (Fig. 1)at a saving of up to$50 by using thescrap material in your"junk bin." We neededonly the cost of a 6 x48-in. sanding belt anda few common hard-ware items.

While the unit in Fig.

1 was fitted to a Shop-smith, it can be adaptedto other power equip-

s

DRILL FOR SHAFTCLEARANCE

BORE FOR BEAR ING-FO RCE FIT

STEEL

DRILL OVERSIZEFOR SHAFT

R

B SIDE RAIL (2REQ.)DRILL FOR BOLT BKT.

GUIDEGROOVES

c BASEHOLES

HOLES FORMTG. RODS

23"

DRILL FOR OUTBOARDBEARING BLOCK

DRILL FOR GUIDE FENCEAND BASE CLAMP BOLT

HARDBOARD

CLEARANCE TABLETOP RELIEVE FORCLEARANCE

IDLERPULLEY

CROSS MEMBERS

SECTION a- aBOTTOM

MOUNTINGRODS FOR

SHOPSMITH

PULLEY(2 REQ. )

DIA.

a

BOLTS

MACH.

OUTBOARDBEARING OVER

PULLEYRADIUS

P U L L E YSHAFTHOLE

d

CARRIAGEBOLTS

d

b

CARRIAGEBOLTS

SIDERAIL A

C

cb

BOLT BKT,

BOLTSCARRIAGEaSECTION b-b

SLIDING BLOCK

BORE FOR BEARING-FORCE FIT

WOOD SCREWS

SLIDING BLOCK

SIDE RAIL

FIXED SIDE RAIL

BOLT WITH LOCK NUTS

SLIDING BLOCK

TURNBUCKLESPACER

SECTION C - C WOOD

SCREW

CROWN CENTER

FLANGE-

RECESSINTOEND

PULLEY

DETAIL#8 DRILL.

TAPFOR

SET SCREW

COVERHARDBOARD OUTBOARD

BEARING

BLOCKTABLETOP

BOTTOM

SIDE RAILS

SECTION d-d

MTG.ROD.

BASE

BOLTBKT.


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ment by modifying the base. Youcan also drive it with a - or -hp motor by mounting it on a suit-able stand and using V pulleys.

Most dimensions in the draw-ings may be freely altered to suitwhat lumber stock you have onhand. For that reason, several lo-cation dimensions for the various

wood parts and bolts are omitted.Make the Pulleys First, sincebelt size and pulley diameter de-termine the table length (sectiona-a in Fig. 2). Long-wearing ma-ple or other hardwood is prefer-able, but pine can be used. If youdo not have 4 x 4-in. or largerstock, glue up a block from twoor three pieces of the hardwood;then cut off two 6-in. lengths.

Before turning the wood, ac-

quire shafts for the drive and idlerpulleys, with bearings to fit. Di-ameters need not be exactly asspecified in the Materials Listwe chose them because they wereon hand. Center drill through thelength of each block for a tightfit with its shaft.

To reduce clearance betweenpulleys and side rails, recesses arebored into pulley ends to takemounting flanges as in Fig. 2A.You can obtain the flanges inmany hardware stores or get pipefloor flanges from a plumbingshop. Buy the sizes that will justslip on your shafts, or you canream them to fit. Drill and tapflange hubs for setscrews as inFig. 2A.

Push a shaft through a blockslide on a flange, attach it to anend of the block with screws andtighten setscrew on shaft. Mountin your lathe, using shaft to drivethe block. Square off opposite endand bore recess for the flange. Re-move from lathe, install flange inthe recess with screws and lockonto shaft with setscrew. Mountthis end of shaft in the lathe and removeother flange. Square off other end until blockis 6.125 in. wide, then bore recess and replaceflange.

Now you are ready to turn the pulley to

approximate 4-in. dia., leaving a .063-in,crown in the middle to insure accurate track-ing of the sanding belt. Make the other pulleythe same way.

Side Rail Belt Adj ust ment. Next cut andshape the sanding table sides as in Fig. 2Band slightly bevel edges. For control of belttension and tracking, cut sliding blocks withcare to insure a smooth, sliding fit in the side

MATERIALS LISTBELT SANDERNo.Req. Size and Descript ion

1 pc 1.625 x 5.625 x 32" pine (base, glu ed-u p fence base b loc k)

1 pc x 7 x 30" pine (table top and bottom, guide strips)1 pc x 3.625 x 43" pine (side rails)1 pc x 2.625 x 72" pine (cross members, sliding blocks, panel baseboard, fence

support)1 pc 1.625 x 2.625 x 20" pine (bolt bracket, outboard bearing block)1 pc 1.625 x 5.625 x 40" hardwo od (gl ue d-u p pull eys, mounting rods)

(if not available, substitute white pine)1 pc x 6 x 15" hardboard table cover )1 pc .375 x 12 x 15" p lywo od ( fen ces )1 .625" dia x 15" steel rod (driving shaft)1 .437" dia x 8" steel rod (idler shaft)4 2" dia steel flanges (for pulleys2 bored.625",2 bored.437")3 .625" I.D. ball bea ring s (for driv e sha ft) (try local garag e, machine shop)2 .437" I.D. ball bearings (for idler shaf t)2 3" common turnbu ckles (for sliding blocks)2 1.188" hose c l a m p s (for mounting rods)2 pcs .063 x x 8" strap iron (clamp strips on mounting rods)

Misc. 2 pr 2" butt hinges, 1 pr 1" butt hinges, 2' #8 wire, 2 "-dia x 2" bind-ing posts, 1 .375 x 6" machine bolt, 2.375 x 5" machine bolts with nuts, 2.375 x 4" carriage bolts wit h nuts, 2.375 x 3" carriage bo lts wi th nuts, 4 x 4" carriage bolts with nuts. 12.375" I.D. washers, 8 1/4" I.D. washers,small piece " steel plate, 2 doz #10 x l" fh wood screws, 4 #8 x .875"fh wood screws, 6 #5 x " fh wood screws, glue

Hardwood rods to fit frame of power unit are wedged tightly into

base and ends sanded smooth. Once sander is aligned with machine,

mark position by attaching hose clamps tightly to rods against

frame. This will ensure easy return of sander, after removal, to

proper working height.

WEDGE FIT,SAND

SMOOTH

HOSECLAMPS

BOLTBRACKET

rail recess as in b-b of Fig. 2. Drill hole foridler pulley shaft slightly oversize and boreon inside edge so bearing fits with force fit.Install bearings.

To retain sliding blocks in their recesses,

cut grooves on a shaper with a 3-wing cutter,using either the glue-joint groove as in b-b ofFig. 2 or a matched tongue and groove cutterset. If you do not have a shaper, you can holdthe blocks in place with small .063-in, steelguide plates attached to each side of the siderails as in b-b of Fig. 2.

For tension on the belt, hook up the slidingblocks to side rails with small turnbuckles as


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Left , acro ss-b elt fence speed s sanding against grain, helps to smo oth or bevel end edges. Fence t i lts back wardonly, to prevent wo rk being wed ged be twee n belt and fe nce . Right, paral lel guide has adjus tme nt slot, clampsat any point best suited to sand w ith the grain or handle side edg e wo rk. F enc e can ti lt up to 45 in either direc-

t ion. Belt is remo ved to show con struction detai l. Note "streamlined" ba ck of fen ce base.

in Fig. 1 and in section c-c of Fig. 2. You may

need spacers under each turnbuckle eye forclearance. As an alternate, try a long boltwith locknuts as in section c-c of Fig. 2. Bolt-head bears against end of the sliding blockand locknuts maintain the tension.

You can eliminate the likelihood of a siderail splitting by installing -in. dia. x 4-in.carriage bolts through its width near eachend.

Assembling the Table. To determinelength, fit pulleys inside sanding belt, extendbelt to full length and measure the clear dis-tance between pulleys. Allow about -in.clearance for variations in belt length. Widthshould equal overall pulley length from flangeends, plus thickness of any washers used be-tween flange hubs and bearings. Make thetable depth at least .375 in. less than pulleydiameter.

Cut the table pieces, then assemble top andbottom to the three cross members as in a-aof Fig. 2, using glue and #10 x 1-in. fh (flat-head) screws. Bevel or round off ends to

clear pulleys.Clamp side rails to table so that the topsare about .312 in. below table top and so thattable end will just clear the drive pulley. Ifbearing holes were bored accurately, thedrive shaft will parallel the table top and beat right angles to table centerline. If not,loosen clamps and reposition side rails to lineup shaft. Reclamp and mark all pieces forreassembly later.

Now cut out and shape the base, outboardbearing block and bolt bracket as in Fig. 2and 2C, but do not drill any holes yet. Fitthe clamped assembly to the base as in d-dof Fig. 2 and position the bearing block sothat table top is slightly higher than theblock.

Position bolt bracket on base next to theassembly as in Figs. 2 and 3. Mark locationof bolts through bracket, base and side rail

on all parts. Remove side rails from assem-

bly, drill all holes marked and fasten bracketto base with carriage bolts. Next, insert car-riage bolts from inside edge of rail, makingsure the heads fit tightly since they will notbe accessible during assembly.

Align side rails with your marks on table,then attach with glue and #10 x 1-in. fhscrews. Assemble the drive shaft and pulleyinto the table, then insert the side rail car-riage bolts in the bolt bracket and clamptightly to the base. Drill shaft hole and in-stall bearing in outboard bearing block, posi-tion it to align with shaft, drill base holes andclamp in place with 5-in. machine bolts.

Complete the sander construction by as-sembling the idler pulley, shaft and slidingblocks and fitting the unit into the side railrecesses. Tighten pulley setscrews on bothshafts. Cover the table top with -in. hard-board of the same width and about in.longer on each end. For firm, flat sandingsurface, board should be about .063 in. higherthan pulleys. Attach the board with four

#8 x .875-in. fh screws, one near each corner,and countersink each head well.Mounting Tips. If you own a Mark 2 or

Mark 5 Shopsmithor a Model 10ER equippedwith power mount adapteryou can mountand drive the sander in the same way as otheraccessories for these units.

Turn two hardwood rods approximately 11in. long to 1.188-in. dia. to fit mounting holesin end of frame. You can relieve the pressureof clamping screws against these rods by rab-beting a groove in. wide and .063 in. deepin the side of each rod parallel to the center-line. Insert strap iron strips in the groovesand secure with countersunkfh screws.

Locate base holes for these rods at rightangles to centerline of the sander drive shaft,while this shaft is in line with the Shopsmithdriving shaft. Drill the holes to take rods ina tight fit, then glue and wedge the rods into

DOOR KNOB

FENCE

BASE


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position with the strap iron inserts facingeach other.

To load your sander, close up turnbucklesenough to slip belt around pulleys and table,then expand the buckles until belt is tight.Connect drive shaft to the power unit, switchon the motor and adjust turnbuckles as nec-essary to keep belt running smoothly in itspath around the pulleys. Try sanding a pieceof scrap briefly to check the movement, makeany additional minor adjustments and yournewest shop tool is ready for use.

Fence Attachments. The basic unit is ade-quate for handling flat wood surfaces but youcan do a neater job smoothing sides and edgesby making the two simple guide fence attach-ments in Figs. 4 and 5. Since each fence ishinged, they can be clamped to hold work at

almost any angle for beveling and some shap-ing operations.

You can build a common base for theseguides by gluing and nailing together twopieces of 1.625 x 5.625-in. scrap (nominal 2x6)as in Fig. 6A. The bottom piece is cut back

just enough to fit around the bolt bracket andallow top pieces to butt against table side rail.In this position, drill through block and sand-er base for long bolt to hold fence in place.Install strips along top edges to guide thefence baseboards.

Make the across-belt and parallel-to-beltguide fences as in Fig. 6B, C and D, usingplywood pieces for the fences and some x

2.625-in. pieces (nominal 1x3) for other parts.To control the fence angle, install both sidesof a 1-in. butt hinge near the top of the fenceand knock the pin out. Thread fairly stiffwire such as #8 through the hinge and bendover the slightly protruding end to keep itfrom pulling out. Bend back other end ofwire and run it through a clamp post on thefence support, then slightly curve wire untilit will permit free movement through the postas the fence is moved into any position with-in its range.

Eliminating Loose Tools. If you have anold brass knob handy, braze it to the head ofthe 6-in. machine bolt used to clamp fenceassembly to sander base. It makes a conven-ient handle as in Fig. 4, and does away withthe need for a wrench. For another time-saver, drill and tap a small piece of -in. steeland attach it in position under bolt hole onbottom of the base. Thus, there is no loosenut to fumble with every time you shift,change or remove fence guides.

Where you use a loose tool such as a smallwrench for the turnbuckles, shape a small

holder for it out of wire or metal sheet andattach it to the edge of the base near theidler pulley. The tool will be out of the waybut always handy when wanted.

Combination Sanding Belt

When a sanding belt becomes worn, cut itdown the middle and use a piece of it to coverhalf the width of a belt of a different grit so as

to form a com bination fo r both coarse and finesanding without belt changing. A drop or twoof glue will hold the narrow piece in line andwill prevent its shifting.R. HAN S COM .

117

HINGERELIEVE FOR

TILTING OFFENCE

D PARALLEL FENCE(SIDE VIEW)

BRASS DOOR KNOBBRAZED TO BOLT

E CLAMPING BOLTDIA. X 6"

MAX,

PLYW. FENCE

c GUIDE FENCEPARALLEL TO BELT

SUPPORT

WASHER

BINDINGPOST

SLOT TO FIT

CLAMPING

BOLT

#8 WIRE

HINGE

6"

4 "

BASE

BASE

PLYW.

FENCE

B I N D I N G P O S T

HINGE

BGUIDE FENCE

ACROSS BELT

DRILL DIA.

OR MODIFY TO

FIT CLAMP

BOLT

AGLUED-UP

FENCE BASEFH

SCREWS

12"

belt sander1

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