Sunday, 24 November 2013
divide and conquer
A simple indexing plate for the Taig. It has both 20 and 24 hole circles, yielding 2, 3, 4, 5, 6, 8, 10, 12, 20, and 24 divisions. In this photo, it still needs a locking pin mounted to the T-slots in the headstock.
The plate was made on a large milling machine using a dividing head. Sure, I could have done it the hard way by dividing the circumference of the disc into equal parts, but I had access to the big machine and the head. Dad always said I was good at "energy conservation".
Ran into some difficulties getting the first plate (I made more than one try, yes) concentric on the darned pulley. After several head scratching moments, I discovered that the stepped shoulders on the original mandrel I made up were not concentric. A new mandrel solved the problem.
The plate is held on the pulley using three 1/4"-20 flat head Allen bolts, countersunk into the pulley back. I have two spare plates in case I need other divisions, like 7 or 13, for some future project.
I could've sworn I'd made the pulley with 24 and 25 holes in case I needed to make up some sort of micro-adjustable feature using a 40 tpi thread at the 25 div option. Those spare plates will come in handy...