THE accompanying engraving shows a practical little kink for turning scollop hand-wheels in a lathe. The writer once had a large number of hand-wheels to be made as shown at O. The wheels were made of bronze and were cast. The outside diameter was to be machined so the job would look mechanical and it required too much time to file the wheels up, so this tool was devised. The forming tool A was made of machine steel to the exact finished size of the hand-wheel. A roller B was made of tool steel, and was of the same diameter as the radius of the scollop in the hand-wheel. Some slight changes were necessary in the lathe to accommodate the working of the tools. The feed screw on the cross-head of the lathe was removed and a coil spring was run from the cross-head of the lathe to the back of the carriage. This spring was made of No, 10 B.&S. wire, which was strong enough to control the cutting of the tool. A double tool post was rigged up and placed on the cross of the lathe carriage. The work was then mounted on the mandrel of the forming tool and placed on the center of the lathe; the roller B was placed in the tool post as shown at D,o the lathe tool E was then secured in the opposite tool post E, and the lathe was started up. The roller B, which is shown in position at D, would roll pver the scollop on the forming tool A, and by so doing would feed the lathe tool into the work in the same manner. A very neat finish was done on the hand-wheels in this manner in less than half of the time it would take to file them to a finish.
This article was originally published with the title "Turning Scollop Hand-wheels in a Lathe" in Scientific American 105, 18, 392 (October 1911)