Gene Heskett wrote: > On Sunday 07 July 2013 01:20:43 Jon Elson did opine: > > >> Gene Heskett wrote: >> >>> Now I can >>> >>> write a peck loop wrapping up the G33.1, that can drive a 10-32 tap >>> half an inch into a prepared hole, backing out to clear chips, and do >>> it in perhaps 45 to 60 seconds. Each direction change, at 300 revs, >>> takes a bit less than 3 seconds for the stop, and accelerate to the >>> same speed in the other direction. Listening to the z stepper growl >>> seems to say that it is totally and absolutely locked. I have killed >>> the motor power in mid cycle, and rolled the spindle by hand, with >>> the z drive following it perfectly, as I expected. ;-) >>> >> I do 4-40 holes with a combined drill-tap in about 12 seconds at 1000 >> RPM. it takes most of the time doing the drill plunge, then the tapping >> only takes a >> couple of seconds. I do 10-32 in pre-drilled holes in about 4 seconds >> at 660 RPM. Those are single-pass tapping cycles in aluminum. >> >> Jon >> > > Chuckle, yes, and I can imagine the cost of the tap to do that. I am using > what I can get at Tractor Supply, Arrgh! I use $8 taps from the usual suppliers like MSC. These are spiral flute combined drill-taps, and bring the chips up out of the hole like a twist drill. You get long needle-like chips from them, and very little clogging. There is a depth limit to them, go above that limit and the chips jam the flute and break the tap. But, for speed when you have many hundreds of holes to drill-tap, you just can't beat them. Basically, if the machine is set up right and the first hole goes OK, the tap never breaks, even after thousands of holes! > with gullets that wouldn't pretend to > have enough room to carry the chip load from a hole that was likely the > nearest fractional 1/64th inch size smaller. But you would be amazed at > what a 3/32" diameter diamond coated bit, laid in the groove, turning slow > enough to not ablate the diamond, used to deepen the gullets by .005" can > do for the performance of such a tap. I've also found the usual Ace Hdwe > Hansen tap breaks like cast iron today, where 50 years ago it was close to > the best you could buy. > Yup, seen that crap, Vermont American was what they sold a few years ago, white sintered stuff that crumbled quite easily. Sears sold similar junk under the Craftsman label. I try to only use machine shop-grade stuff now, and keep an extra one or two new taps in most sizes so I don't HAVE to run out and buy the junk at Ace.
Jon ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
