Boys' Make-at-Home Things :: HOW TO MAKE A TURNING LATHE

HOW TO MAKE A TURNING LATHE

MOST boys have a speaking acquaintance with a turning lathe. Some boys know how to use one with good results. But to use one and own it too—that is a joy which few boys experience.

After all, though, a lathe is not such a formidable machine, and if a boy is quick at catching an idea and working it out he can make one for himself.

Most of the material can be procured from some machine shop at practically no cost, and the parts that have to be bought outright will cost very little.

The foundation may be an old sewing-machine stand and the lathe is run, just as a sewing machine is, by foot power. In almost any junk shop or second hand shop you will find an old out-of-date sewing machine for sale. New machines can be bought so cheaply nowadays that a second hand one costs next to nothing.

When you have procured this you must take it to pieces. The wooden top part is fastened to the iron frame by screws from underneath. Take these out, and the top and drawer at the sides may be lifted right off. Then take out the screw at the right hand side of the machine part and slip off the upper belt wheel. This upper belt wheel, the belt, the lower belt wheel, and the iron framework of the machine are all that will be needed for the lathe, and the rest you may discard, or put away in the “handy” pile for some future construction. The lower belt wheel is of course fastened to the frame, so that does not need to be disturbed.

Next get a piece of hickory or some other hard wood twelve inches wide, three feet long and one-and-one-half inches thick. Cut a long, narrow slot in this from one end as is shown in Fig. 1. Then fasten this piece to the top of the iron frame with the same screws that fastened the top of the machine on before. The solid end of the wood should project two inches beyond the right-hand end of the frame where the belt is, and the slotted end will of course extend somewhat beyond the frame at the left. This is what is called the “bed” of the lathe. Now bore the two holes which the belt goes through.

When this is done, measure the hole in the center of the upper belt wheel, where the shaft went through. It will probably be one half inch in diameter. Then get a piece of gas pipe twelve inches long and of the same diameter, outside measurement, as the hole, so that the wheel may be put on it with a “drive fit.” This simply means that the wheel fits so tightly that it must be driven on and, once on, it will not turn. It should be driven on far enough so that when the groove for the belt is in line with the groove on the lower belt wheel, the pipe will project the half inch beyond the solid end of the bed.

Now you must make two supports, or “head blocks” for this. Cut from two-inch-thick hard wood two pieces like Fig. 2. The square hole is for the gas pipe to go through and must have a bearing fitted into it. Of course it would be easier to cut just a round hole slightly larger than the pipe for it to turn in, but this bearing, with much turning, would wear loose. So a one-inch square hole is cut; the gas pipe, with a piece of newspaper wrapped around it, is held in the exact center of the hole, the head block standing upright; and melted Babbitt metal is poured down through the hole in the top of the block. To do this pieces of cardboard should be fitted over the pipe and tacked to either side of the block, so that the space inside is like a mold. The metal which remains in the top hole forms a key to hold it. The Babbitt metal may be bought at a hardware store in small bars and melted in a kettle in the fire. It hardens quickly and when hard, the pipe may be removed, the paper taken off and you will have a permanent, durable bearing.

Diagrams of a Turning Lathe.Slip one of these head blocks on the pipe from each end, with an iron washer on each side of each block. The right hand block should be “flush” with the end of the bed, the pipe projecting a half inch beyond it. The other block should be spaced two inches back from the ends of the slot in the bed. The blocks are fastened to the bed with long wood screws which come up through the bed from underneath, and they are held in position on the gas pipe by making “prick punch” holes through the pipe close to the washers and using either “cotter pins” or bent wire through these. Then the end of the pipe, which projects over the slot should be filed so that it has four points, or teeth. This completes the head of the lathe, and is much the most complicated part.

The rest of the lathe consists of a “tail block” and a tool rest, both of which are adjustable to any position desired. Fig. 3 shows the tail block. Like the head blocks, it is made of two-inch thick stock. The bottom of it is cut to slide back and forth in the slot. Just underneath it, on the under side of the bed, is a piece of wood four inches by two inches and one-inch thick which is fastened to the tail block by a screw through the center and which clamps the block in position at any required distance. At the point marked “P” a “lag” screw, which is simply a wood screw with a sharp point and a large flat head, is screwed through the block. The piece of wood to be turned is held in place by this lag screw and the filed teeth on the gas pipe.

The pieces of the tool rest are shown in Fig. 4 and Fig. 5. Fig. 6 shows it as it looks when it is put together in place on the bed of the lathe.

Fig. 4 shows the tool rest itself—that is, the part upon which the chisel or gouge is steadied for cutting. This is fastened upright upon the end of Fig. 5, which is a standard which extends across the bed and is clamped in place, as the tail block is, to a block underneath, except that, instead of being screwed, it is fastened with a three-eighth inch bolt and nut.

Fig. 7 shows the whole lathe “assembled,” or put together with each part marked according to its figure numbers so that you can see just how it goes.

Fig. 7

All the material it has required has been:

One old sewing machine.
About fifty cents’ worth of hard wood.
One three-inch lag screw.
One three-eighths-inch bolt five inches long, with nut and washer.
Four iron washers for gas pipe.
One foot of gas pipe.
Seven three-inch wood screws.
A few cents’ worth of Babbitt metal.

The result is a good practical lathe on which anything up to eight inches in diameter and twenty-one inches long may be turned; and I think you’ll all agree that it was well worth the making.

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