On Monday 27 August 2012 19:19:02 Jon Elson did opine: > Gene Heskett wrote: > >> But, I have done a lot of 10-32, 4-40 and 2-56 tapping in aluminum. > >> I use "alum-tap" with is a fantastic tapping fluid. > > > > I've been meaning to get some of that, I keep forgetting it when I'm > > on the phone ordering other stuff. But alum-tap or aluma-tap? > > Sorry, I've been off vacationing in the Ozarks. It is AlumTap, by > Winbro. > > > The 10-32 stuff has always cut sweet even in steel, but lots of rack > > rails are tapped 12-24 and I recall one RCA rack back in the 60's > > that was tapped 12-32! And one from the J. A. Pan Co that I couldn't > > find the right metric screw for & wound up drilling to 12-24, the > > whole 7 foot rack. > > Umm, 12-24 is an obsolete thread, and has been since WW-II or before. > You must be running > into REALLY old racks. > Broadcasting is an old business. The gear mounted in the rack may change, but lots of 1030's era racks still exist in the back rooms away from the public view, in radio stations in particular.
> >> I have done > >> thousands of 4-40 holes > >> in 3003 and 5052 aluminum with combined drill-taps, and some others > >> with spiral-flute taps, typically at 1000 RPM, and go full depth in > >> one pass. > > > > I have done quite a few 6-32 holes in 7078-T6 but can't claim a lot of > > experience in tapping the common alu stock sold at Lowes/TSC, its > > pretty soft. ISTR the last batch of 4-40's I tapped about 3/8" deep, > > blind, took about 4 trips back out to clear the chips. Not much chip > > room in a common hand tap. > > I've tapped 6061, 2024, which tap nicely, and 3003 and 5052, which need > a good tapping fluid > to glide the tap in, as these are more gummy alloys. Their advantage is > that even thick sheet > of the 3003 and 5052 are bendable. > > Jon > Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! You will remember something that you should not have forgotten. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
