On 7/7/2013 1:51 AM, 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, 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. > > So today I look for the MIBRO brand, they are not only sharper, but can > take 2 to 3x the torque a Hansen tap breaks at. Sure, they aren't a $30 > tap from Henly, but they do a fine job for a 7 dollar bill including the > right size tap drill. My problem is keeping the tap and the drill together > after removal from the blisterpack card. I should make me some box covers > for brass storage plates, with the plate having 2 holes drilled in it with > each tap drill, and one of then tapped for the tap so they are always > together. I'll probably do that right after I find my missing round tuit. > :) > > The best small drill and tap storage ever was the little plastic& > cardboard sleeve they shipped rifle ammo primers in 50 years ago. I still > have one of those with all my 6-48, 8-40& 10-32 taps& drills (some of > those are carbide) stored in it. > > Cheers, Gene > Gene,
Do you have a Menards near you? The tap/drill pairs that they sell hold up well. I think they are $5.00 for an 8-32 set. I use them to drill and tap holes in steel control panel backplanes and they do ok. I chuck the taps in a cordless drill and go to it with a touch of lube I break very few of them. I've used nice spiral point taps but they last about the same. You are right.. ..Hanson used to be very high quality. Dave ------------------------------------------------------------------------------ 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
