I have been having trouble taping delrin, the finished threads are too small.
I think the delrin is expanding and bending with the tap shape.
M8 x 1m tap in 10mm dia delrin, drilled and tapped on lathe.
Any hints? Any substitute for delrin, but a bit harder? Are there harder and softer delrins?
thx,
-- Peter Fairbrother
Yes it is expanding as you tap. If it is a one off or small quantity, put it in the freezer overnight then re-tap with a brand new tap
What about whipping string around the 10mm diameter to prevent it expanding?
Best chance is probably hold in 10 mm collet and use a new tap.
There are taps for plastic which are hooked but very expensive.
Lots of alternetive plastics BUT its pot luck which would suit you.
Regards Colin
Other than the suggestions of freezing it or putting it in a collet (both good), If you've got a T&C grinder, Grind a very sharp rake on the tap.
Regards Mark Rand
Idiot me! I meant to also suggest single pointing it with a sharp tool...
Regards Mark Rand
There is a danger you may make delrin brittle, even with domestic freezer temperatures if I remember some of the details from my undergrad year, all but 40 years back. While it was many years back, I vaguely recall something about a dramatic change in acceptable elongation before breaking. You could easily 'strip' your new threads by shearing them as you cut the next ones.
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