Herbert O. Bacon
The frequent breaking of small twist drills when used in a hand drill upon metal, led me to make the holder for the hand drill with foot-power feed, which is here described, and the use of which greatly reduced the breaking of drills, and afforded other advantages quite evident to any one familiar with work on a drill press. In this device the drill moves, the table is stationary, which permits of placing the work at any angle in relation to the drill and fastening the same when necessary to guard against any movement.
The exact dimensions of the different parts will depend upon the size and shape of the hand drill, but the different makes vary but little, and therefore the specifications given will be suitable for most kinds. The principal points to be seen to are: That the hand drill is securely fastened to the frame and that the frame is strongly constructed without side play, as it is the latter that causes the drills to break.
The general make-up is shown in the illustration. Obtain a piece of spruce plank 3 ft. long, 6 in. wide and 2 in. thick, which will plane up to 1 3/4 in. thick. Also four feet of 2x3 in. spruce, which will plane to1 3/4 x2 3/4 in. and from which cut three pieces, 12 in. long and one piece 10 in. long. One of the 12-in. pieces is put across the top of the plank, one forms the lower carrier of the sliding frame, and the third piece supports the table. The 10-in. piece is for the upper carrier of the frame.
To the carriers of the sliding frame nail two strips about 6 1/2 in. long, 3 in. wide and § in. thick, between which are fastened the two arms for holding the hand drill. The arms are cut out to the shape shown, and of dimentions suitable for the hand drill to be Used, and are securely fastened with screws to one of the vertical pieces just mentioned, and then to the carriers. The other vertical piece is then put in place, and two angle irons put on to prevent side play. The outer ends of the arms are then recessed to fit the hand drill, which is held in place by two clips. (Sleigh clips can be obtained of any carriage supply dealer or repair shop.) These clips have flat iron centers with threaded ends. They are bent to an U-shape to fit around the hand drill, holes being bored in the arms to receive the threaded ends, and the nuts are then tightened up, holding the hand drill firmly in place.
The hand drill frame slides upon two rods, which may be of brass tubing or drawn steel shafting 3/4 in. diameter and 18 in. long, or 1-in. hickory dowel rods may be used. Holes are bored part way into the upper cross piece and the piece under the shelf, and clear through the two cross pieces on the drill frame. Care must be taken that these les are accurately spaced and in line, especially \n the sliding frame, to avoid friction or bends in the rods, which would prevent the frame from sliding easily. After boring the holes, those in the frame should be smoothed up with a round file, to give an easy fit to the rods. When properly fitted the table, a piece of oak 15 x 12 x 7/8 in., is attached with screws to the support, the holes for the rods put through this board, and the parts assembled; the table is then secured in place. Braces are fastened on either side of the back plank and to the front of the table.
Two screen-door springs are then attached to the under piece of the frame and top cross piece, as shown in the illustration, using heavy screw-eyes for fasten\ ing. The springs should have tension enough to hold the frame at the top of the rods, and yet allow it to be brought down easily when the pressure of the foot is applied to the lever underneath.
The treadle needs no description, being simply two boards, jointed with a strong T hinge on the under side. A piece of sash cord is attached to the center of the lower cross piece of the frame; carried through a hole in the table, on the under side of which is an ordinary window pulley, to the treadle, in which a hole is bored, the cord being knotted underneath. Graphite is a good lubricant for the rods, as it prevents wear of the cross pieces.