Thanks for the tips guys, I shall keep them in mind
Getting the bits ready to weld
I made another fixture to fit the holder to make a square hole cutter. The tip is a small HSS lathe tool held in the bar which was in turn held in the lathe. When spun at high speed I used a high speed grinder with a ball stone held against the end to form the cutting shape.
For a trial run I drilled a hole in a bit of alloy stock
Mounted it on the shaper and cut the round hole into a square one ...
It worked very well, and quite quickly too. But every now and again the workpiece left the room, well the vice at any rate. OK, I know it's not very secure, it was only a quick test, now I need to make a fixture to hold the workpiece properly instead of the vice.
I have a sort of angleplate with a hole in it in mind ....
The keyway slotting tool, needs thinning but you get the idea