What is the secret of these things. I just burned up a 1/2" HSS mill. Do you run at them at RPM for the inside diameter, the outside diameter or some place in between?
Also, how do you flood cool them? IF you flood from the top the outer circumfrence slings the opil off and the center gets hot. If you spray it up from below the outer edges don't seem to get enough oil.
I never run at the calculated speed on any form cutter. I would run maybe 1/3 less than the speed for the outside, and decrease the feed accordingly. And you can hog off a lot beforehand with a regular end mill, too, which will decrease the load on the form cutter. Can't help with flood coolant, don't use it.
Grant
Glenn Ashmore wrote:
--Just kiss the edge of the part with the i.d., then feed the part up with the Z-axis. Take two passes or even three to get the desired results. Use spray mist if you can arrange it. As for surface feet per minute: do it based on o.d., not i.d.. It'll be a little slow for the small end, but that's OK. Make a clean-up pass (conventional mill, not a "climb cut") when you get what you want; this will knock off any burrs.
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