B. R. Wicks

Continuing the work of machining the bench grinder, lay out the boss for the bearing of rest No. 1 central with the boss and square with the spindle bearing, and drill and ream to 1/2 in. diameter. The front of this boss can be faced off with a counterbore and filed and polished, but this is only done for looks.

The two bosses on the back of the spindle bearing, which are for the spindle adjusting screws, are to be laid out, drilled, counterbored and tapped. When the centre of the bosses have been located and centre punched, first drill all the way through with a 3-16 in. twist drill. Have at hand a counterbore with a 3/8 in. body and 3-16 in. pilot and counterbore down to the depth of 3-16 in. Enlarge the 3-16 in. hole to the depth of 1/8 in., with a 17-64th in. twist drill, and tap out the remainder of the 3-16th in. holes with a £-20 thread tap, as in section C-D on drawings.

The 1-16 in. slot for the take-up piece and the oil groove will be put in after the spindle, B, has been turned and fitted, which will come later.

The £ in. boss on the top of the spindle bearing is to be drilled all the way through to the 9-16 in. boss with a £ in. twist drill and enlarged with a No. 1 twist drill to the depth of 5/8 in. and tapped out with a £ in.-32 V thead tap for an oil cup.

There must be a 3/8 in.-16 thread tapped hole in the side of the frame, central with the thickness of the casting and exactly central with the £ in. hole in the boss, to hold the set screw, K, which holds the rest No. 1 E, in position when the machine is in use.

Tap this hole 3/8| in.- 16-thread U. S. S. and use a 5-16 in. twist drill for the tapping 6ize. L is the shoe that works against the 3/8 in. flat on rest No. 1, E, to keep it in position, and also to avoid screw K from cutting in the | in. flat on rest No. 1, E. This rest is made of a piece of 19-64 in. brass rod and cut off and finished to 3-16 in. long, and placed in the | in. tapped hole when the machine is ready to put together. Screw K is a regular screw cut off and hardened to the figures given on the drawings.

The spindle, B, is made from a piece of round machine steel 6 15-16 in. long and 15-16 in. diameter in the rough, and is drilled, centred and turned up between centres to the figures given on the drawing. Both the £ in. and 9-16 in. diameters of the spindle must be turned exactly straight, and true and smooth for good results from the machine. Allow enough on both diameters to file and polish, and fit the spindle to the 9-16 in. reamed hole in the frame, A, which forms the spindle bearing.

After filing the spindle, finish with fine emery cloth and oil using, as before stated, the 9-16 in. hole for a gage. The thread on the end of spindle B can be cut in the lathe, but if the builder has not a screw cutting lathe it can be done with a die. The die stock should be provided with a £ in. guide to insure a straight thread.

The thread to be cut on spindle B is 1/2 in. 13-thread U. S. S. 1 1/4 in. long, right hand. There is one £ in, 13-thread semi-finished nut wanted which should be case hardened.

The two wheel flanges, D, are made from grey iron castings, and are to be chucked, centred, drilled, reamed and turned. The flange that fits against the 3-16x7/8 in. shoulder on spindle B must be bored out a little less than £ in. the diameter of the flange end of the spindle to allow for a shrinking fit. After having bored out this flange force it on a mandrel and turn the back face that will fit against the shoulder on the spinale true. The remaining part make about 1-32 of an inch larger than the drawings. Heat this flange to a good cherry red and tap the spindle into the hole and be positive that the face of the flange and the face of the 3-16x7/8 shoulder on spindle B come up tight together ; let it cool off (do not put it in water). When cooled put the spindle between centres and finish up the flange to the drawings and polish with emery cloth and oil. The other flange is bored so that it will slide on the spindle, and finished up In a £ in. mandrel to the drawing. When in the chuck do not neglect to put in the recess 3-64 in. deep.

The pulley, C, is made from a grey iron casting. Chuck the casting and drill and ream ont to 9-16 in. diameter.; force it on a 9-16 in. mandrel and turnup to 2 in. diameter. Face the two sides of the rim, making it If in. wide. Face up the hub £ in. from the rim on each end, making it a total length of 17/8 in. The pulley will now be crowned from 2 in. in the centre to 1 15-16 in. on the sides, as in the drawing; file, and polish with emery cloth and oil. There will be two £ in. 20-thread tapped holes to be made in the hub for the two£ in 20x£in. headless set screws. J, which will hold the pulley C in position on the spindle, B. Lay these holes 5-16 in. from the rim and central with the diameter of the pulley, and centre punch mark and drill all the way through the rim and hub with a 3-16 in. twist drill, and tap out the 3-16 in. holes in the rim only with a 3-16 in. twist drill. Enlarge the holes in the rim only with a 17-64 in. twist drill and tap out the 3-16 in. holes in the hub with a £ in. 20 thread U. S. S. tap. The two set screws, J", are regular sizes and will not have to be made up by the builder. Two of these screws are wanted.

The rest, No. 1, E, is made from a piece of 11-16 in. square cold drawn steel, 4 15-16 in. long.

Note. The drawings and previous portion of the description appear in the August number.

Polish off the side of the steel, rub on a little blue vitriol and lay out the 7-16 in. hole for the rest, No. 2, F, to work in. Prick punch where the lines cross and start in with a small drill, abont 1/8 in. or 60, and drill all the way through. Then drill with a 28-64 in. twist drill, and finish out with a 7-16 in. lathe reamer.

The piece will now have to be centred; take it from corner to corner and drill and countersink, and between centres turn the i in. diameter that is to fit into the 1/2 in. reamed hole in the boss on the frame, A. This must be turned straight and smooth to the length of 4 in., leaving .002 to file and finish with emery cloth and oil. It must fit the 1/2 in. hole and slide in and out without any shake. The flat on the side is 3/8 in. wide 3 13-32 in. long, and can be either milled or filed. Do not fail to.notice the location of this flat with the 7-16 in. hole.

The end can be finished up between centres with a round pointed tool. The \ in. hub on the 11-16 square end is now drilled into the 7-16 in. hole with a £ in. twist drill, and tapped out with a 5-16 in. 18-thread U. S. S. tap. The four sides can be draw filed and polished with emery cloth and oil.

The rest, No. 2F, is made from the same stock and machined in the same way. The only exceptions are the length, diameter, and the set screw to be used in the end. The 7-16 in. diameter of rest No. 2, F, fits in the 7-16 in. hole in rest No. 1, E, and must be a good sliding fit without any shake. The 11-16 in. square end is drilled with a 3-16 in. twist drill and tapped out with a 1/4 in. 20-thread, U. S. S. tap.

There will be one of each of the screws shown on the lower right-hand corner of the drawing. These are to fit the ends of rests No. 1, E, and No. 2, F, and are made from regular set screws cut off to the figures given on the drawings, and the heads drilled in and hardened. The drawings show the position of these screws when the machine is assembled.

The tool rest, H, is made from a grey iron casting and is laid out by the 9-16 in. boss on the bottom of the castings, and drilled and reamed out to 5-16 in. diameter, forced on a short mandrel and faced up 3/8 in. thick. The under part does not need to be machined. The 5-16 in. hole is slightly countersunk so that the tool rest spindle, C, can be riveted in. The tool rest spindle, G, is made from a piece of |x2 7-16 in. Bessemer steel. One end must be turned down to drive in the 5-16 in. hole in tool rest, H, ahd be riveted, draw filed and polished on the top and edges.

The remaining work to bedone will be to put in the oil graove ,saw the bearjjsg through with a 1-16 in. saw, make the spindle adjusting piece, paint and assemble. The oil groove in this case can be filed in with a 1/8 in. rat tailed file, starting in on one end and then turning the piece end for end until the groove is made. To saw out the 1-16 in. slot a milling machine will have to be used. Set the casting in the vise by the two finished ends of the spindle bearing and set the 1-16 mili exactly central with the 9-16 in. hole and central with the thickness of the two bosses, as in section C-D on the drawing, slowly feed in the saw and cut the 1-16 in. slot all the way through. Remove from the vise and with a fine half round file, file out the burr left by saw.

The spindle adjusting piece is not shown on the drawings. It is made from sheet brass 1-16 in. thick. Take the piece of brass, file off any burr that may be on it and slide it into the slot within 1-32 in. of the spindle on each end, mark around the casting and locate the two 17-64 in. holes, with a sharp scratch. Now remove and drill the two holes with a 17-64 in. drill, file down to the lines and the piece is done. Make the length of the piece about 2 15-32 in. long. The adjusting piece can now be replaced, and the two spindle adjusting screws which have been made and hardened screwed in their places in the bosses.

The spindle, B, can now be placed in position in the bearing. Screw down the two adjusting screws on both ends until the spindle will turn freely in the bearing without any shake. If the adjusting piece proves to be too thick to get the proper adjustment it will have to be taken out and draw filed until the proper adjustment can be obtained. The only remaining work is to assemble the various parts and paint or enamel the machines. As all the parts are named and the bearings clearly show how and where these parts are to go, there should be no trouble in assembling and putting the machine in operation.