Tangential Tool Grinding Jig

To grind tool-bits for the tangential tool-holder, an alignment jig is needed. This jig takes advantage of the large tool supports that I've fitted to my bench grinder.

The design of this is very similar to the one described on the Mike's Workshop page: I shamelessly plagiarised his excellent design. Like his, it is made out of two pieces: a block with a 30° surface with a v-groove cut into it and a piece of bar material for aligning the jig with the edge of the grinding rest.

Manufacture

It took me a long time to work out how to make this jig, but in the end it was fairly simple. I mounted the block of aluminium in the milling vice and used my digital angle gauge to get it as close as possible to 30° to horizontal. I then milled the flat using a fly cutter. Finally, I mounted a 12 mm end-mill in the spindle, rotated the spindle by 45° and lowered the column until I had cut a v-groove of a depth that looked reasonable. I doubt that this was the most accurate way of doing it, but it seems to have worked adequately. After the v-groove was made, the rest was just a case of drilling some holes and tapping so that the bar could be mounted on the bottom.