8/14/2019 Plans for Radial Drill Press

1/4

POPULAR MECHANICS64

ARM BEARINGCAST IRON

DETAIL OF TRAVERSING SCREWAND ELEVATING GEAR

WORM SHAFT

WORM-SHAFTBEARING

WORM

TRAVERSINGSCREW

What the Giant Radial Drill

Is to the Large Shop ThisLittle Drill Press Is to the

Small One; It Can Easily BeAdapted to Power Drive, Us-ing an Ordinary Electric Drill

PIVOTBAR

WORM-WHEEL NUT WORM

PIVOT BEARING,CAST IRON, 2

REQUIRED

SECTION OF THREAD

DETAIL OF ARM

FLAT

PIVOT-BAR DETAIL

4 THDS PER INCH

8/14/2019 Plans for Radial Drill Press

2/4

A Radial Drill Press for Small Shop

By J. V. ROMIG

OST mechanics, while appreciat ingthe value of the radial drill press in

the large shop, and realizing what a helpsuch a tool on a smaller scale would be inthe small experimental shop, look upon itsconstruction as beyond the scope and ca-pac ity of the sma ll shop. Such is not thecase, however, as a glance at the accom-pan yin g dra wi ng s wil l prove. In this de-sign, the machine work necessary hasb e e n r e d u c e d t o t h e m i n i m u m , a n d a l l o f i t is w i t h i n the capacity of a sho p equ ippe dw it h a good lath e. A drill press of th istype is capable of a much wider range ofwork than the ordinary post drills andbench drill presses found in the small

shop. As it can be sw un g back agains tthe wall when not in use, it can be usedw h e r e b e n c h r o o m i s l i m i t e d ; i t w i l l d r i l lholes anywhere within a 38-in. radiusfrom the pivot bar, and thus is of specialadvantage on sheet-metal work, on heavy jobs that cannot be handled easily on ac-count of their weight, and where holes

must be drilled in the center of pieces oflarge diameter.

The arm is made of 6-in. channel iron.,cut to the length shown in the drawing,and wi th one f lange cut away for a p o r -tion of its len gth . To the rear end isbolted a casting that forms the pivot bear-ing: the dimensions of this bearing aregiven in a detail, and it is split and fittedwi th capscrews and a cl am pi ng lever. Theslide for the drill head is made of a 36-in.

M

Perspective View of the Finished Radial Drill, Show-ing the General Assembly of the Parts

length of by 4-in. cold-rolled steel; thisis fastened to the arm by means of -in .flat-head machine screws, which go all theway through and are fitted with nuts onthe inside face of the channel. Betweenthe slide and the arm is a filler strip of .375by 3-in. cold-rolled steel 32 in. long,machi ned to 3.125 in. in width. Both of

CAST-IRON BENCH BLOCK

INTERCHANGEABLE.

HANDWHEEL

TRAVERSINGSCREW

SPINDLE.

NUT

VERTICAL FEED

GUIDE RODS

STEEL SLIDE

WORMELEVATING

NUT

CHANNEL IRON

ARM BEARING

PIVOT BAR

PIVOTBEARING

8/14/2019 Plans for Radial Drill Press

3/4

POPULAR MECHANICS66

4 HANDWHEEL

FEED-SCREWBEARING

NUT

GUIDE ROD

THD. FEED SCREW

TAPPEDFEED NUT, DIVIDEDON CENTER LINE

PIVOTBAR

ARM

BEARINGDIAM. SPINDLE.

AXIAL HOLE

GIB SCREWS

KEYWAY

CHANNEL

IRON

SHIMSTRIP

SLIDE

SHIM

TRAVERSINGSCREW NUT

SIDE VIEW

FEATHER KEY

MORSE TAPER

BEVELGEARS

END VIEW

Details of Construction and Assembly of the Drill Head or Saddle; Bronze Bushings May Be Fitted to theSpindle Instead of the Plain Bearings Shown

DRILL-HEAD AND SADDLE DETAILS

these cold-rolled pieces must be very care-f u l l y straightened and the edges scrapedtru e. It is also necessary to take care thatthe slide and the pivot bearing are squarewith each other.

The pivot bar is made of 2-in. cold-rolled steel, threaded for 18 in. of itslen gth . The threa d is of sharp V-fo rmat the bottom, but flattened on top, asshown in the detail; this provides a sur-face for the bearing, while not interferingwith th e fu nc ti on of the screw. Theworm wheel is used to elevate the arm tothe desired height; it is made of bronzeto the dimensions given, and is actuatedby a steel worm on a shaft extending to abearing on th e fr on t of th e arm. The

pivot bar is held against the wall by pin-ning it in bearings at each end, which, inturn, are bolted to a stout stringer fas-tened to the wall by lagscrews or expan-sion bolt s. A pl u m b bob is used to set thebar exactly verti cal on the wa ll. When inuse, the arm may be held fast in any posi-tion on the pivot bar by means of theclamp screws.

The drill head, or saddle, is a casting,machined to fit on the slide and drilled

spindles . The bearin gs are sp li t; thefront half of the casting also has the bear-ing fo r the crank spindle. A sui tab le pairof bevel gears, of 1 to1 ratio , are pu r-chased, and the larger gear is pinned tothe crank spindle, as also is the crankhandle; the spindle is in. in diameter,and the bearing is drilled for an oil holeas in the draw ing. The small gear is fit-ted with a feather key, and, when in placeon the spindle, rides on a fiber washer.The spindle is turned from good machin-ery steel, and is bored at the lower end toNo. 1 Morse taper. A groove is tu rn edin the upper end to take the feed nut, anda .437-in. ho le bored axially to clear thefeed screw. The groove is hig hly finished.

The feed is effected by means of a splitnut of novel design, which is a nice run-ning fit in the groove in the spindle and isthreaded internally to fit the feed screw.It is prevented from turning by two guideposts, one on either side, the posts alsosupporting the top bearing of the feedmecha nism . The nu t mu st slide freely onthe posts, and is provided with an oil hole.The posts are screwed into a steel collarwhich is fastened to the top of the upper

8/14/2019 Plans for Radial Drill Press

4/4

POPULAR MECHANICS

upper feed-screw bearing, and to the topof the screw is pinned a small handwheel.The spindle bearings can be fitted withbronze bushings if desired; and this is,in fact, preferable, as it will add to the lifeof the mac hine.

The top of the upper saddle slide, bear-

ing on the rail, is tapped for two -in. set-screws, which are used to adjust the gib tothe slide. The gib is made of sheet brass,bent up at each end to prevent it fromcoming out, and both the upper slide andthe gib should be drilled for oil holes. Abrass or bronze nut for the traversingscrew is screwed to the lower surface ofthe saddle, and a bearing for the screwand the worm shaft is fastened to thefro nt of th e arm. The ends of both thescrew and shaft are squared to fit an in-

terchangeable handwheel .A good table or faceplate can be made

from an iron bench plate, and care should

be taken to see that the press and the topof the plate are square with each other inever y dire ction . The best location for thedrill is near the end of the bench, so thatthe drill can be swung over the end of thelatter for work that cannot be raised tothe bench. A d ri ll chuck of -in. capacity

is fit ted to the spindle; although the gearsare strong enough to drive drills largerthan in., it is seldom, in the small shop,that larger drills will be used in the ma-chine. Larger holes, how eve r, may bebored with a boring bar held in the chuck.

The head may be modified with verylitt le trouble to make the tool power-driven, by using an electric drill andmounting it on a saddle designed on thesame lines as the one shown, but modi-fied to suit the dr il l. If th is is done , the

tool would be an ideal one for the garageor woodworking shop as well as the smallmach ine shop.