Making Small Ratchet Wheels in a Lathe
Accurately formed ratchet wheels of small size may be made without special appliances in a lathe. A triangular file and a simple gauge, made of a piece of hardened steel, are the only tools required, as shown in the illustration.
Ratchet Wheels may be Cut Accurately with a File, Using a Hardened-Steel Gauge as a Guide
The lathe is prepared as an index for the ratchet wheels by dividing the face of one of the steps, preferably the largest of the cone pulley. A center punch may be used in marking the graduations slightly, and another point should be marked in the headstock base, from which dividers are used to gauge the movement of the spindle. The dividers should be set, when the work is begun so that one point rests in the punch mark on the headstock and the other in one of the marks on the pulley. The bearings should be tightened so that the work will not shift easily. The blank to be cut is supported on an arbor provided with a shoulder, and is held in place by a small machine screw threaded into the end of the arbor.
The teeth are cut by filing them with the gauge as a guide. If the spindle is turned carefully so that the dividers register the graduations precisely, the ratchet wheel will be cut accurately. By first roughing out the teeth and then refiling them with a fine file, a more smoothly finished surface will result. Other forms of teeth might also be made if a properly shaped gauge is provided.—Charles F. Merrill, Hopedale, Mass.