Worm wheels of sufficient accuracy for dividing and indexing are difficult to make in the home workshop. While they can be hobbed in the lathe or mill if one makes up a spiral hobbing cutter, without special equipment such as Jeff Thyer's attachment in MEW 258-9, the teeth can end up varying in width, throwing off the accuracy for precision indexing needed for gear cutting.Being loathe to pay shipping on a pair of commercial worm wheels from the other side of the world, from a supplier who did not answer email enquiries, I dived once again into the scrap box. No 60 tooth worm wheels were found but it did yield up a pre-war Myford lathe change gearthat could be pressed into service. It checked out at 60 teeth, 20 diametric pitch, 14.5 pressure angle. This was perfect to adapt as the larger gear on the Versatile Dividing Head's main spindle, the lower gear shown in photo 1.
展开▼
