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Weird thread-like thing I need to turn


Jan 26, 2014
Colorado USA
Hi all, so I've got a somewhat strange thing I need to turn on the Hardinge. It's not a threaded cylinder, but, it'll pretty much look like one; it needs to have a 0.010"-wide 'radiused slot' type form (vs a typical 60deg thread form, say), at a pitch of 48 tpi (so my T10 will do it no problem). (This thing is for winding around and embedding a several-meter-long length of optical fiber on, by the way.) I guess my question is, would I do this with the compound at 29.5deg like a v-shaped thread, or should I go at this 'straight' with the cross feed motion? I can't say I've ever machined anything like this before. I reckon I'll either attempt to make a tool with this minute radius on it, or maybe buy one from somebody if anybody out there makes such things...the material will be either 6061 aluminum or copper, and about 1.5-2" in diameter. The cut depth is real shallow, just a few thou...thanks, and I look forward to some words of wisdom! Charley

L Vanice

Feb 8, 2006
Fort Wayne, IN
48 TPI is .020....? Big order or just a few?
if it is a few thow deep I would go straight in with a 12* -15* back rake sharp HSS tool bit for aluminum..likey the same ok for copper.
I agree. There is no reason to use the compound to feed this shape tool, so just do it in one pass (if it is really shallow) with the depth of cut set with the cross feed. Pure copper is not pleasant to machine. Aluminum 6061 will be better to machine.

If there is money to buy tooling, these people can supply exactly what you need.

Other wise, I would just start with a HS cutoff blade and hand grind a tool.

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