Cylindrical grinding a tap on my Hercus
Toolmaker needs to tap 30mm M6 into Aluminium, and is as cheap as me. Instead of one of us doing a hack job on a bench grinder (one of these days I'll make a jig), decided to setup my Hercus with a little grinder.
Started with the chuck:
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but the runout was terrible, so made use of one of Peter's collet holders:
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Failed to get a good action shot showing any sparks, but I was going VERY slowly – only 2 or 3 thou off each pass, and mostly hand feeding because my slowest auto feed was too much. End result pretty good:
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About 1mm off the wheel diameter, and about the same off the tap shaft!
There is a slight step, more runout further away from the collet.
Might be a bent tap, might be my imperfect collet taper machining.
Attached Images
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