On 8/17/2012 8:27 PM, Gene Heskett wrote: > On Friday 17 August 2012 20:12:35 Jon Elson did opine: > >>> On 17 August 2012 15:49, Gene Heskett <[email protected]> wrote: >>>> Also I believe, it would be valuable to have a discussion of the >>>> various offerings, so that I for instance, who might have a need for >>>> tapping 40 each 6-32 to 10-32 holes to a depth of perhaps 1/2" >>>> occasionally, might stand a chance of actually buying something that >>>> works better that I can do. So far as I know, no mechanical tap >>>> driver can do that, the 6-32 needing several reversal extraction >>>> cycles to clean and re-apply the cutting oil if any hope of reaching >>>> that half inch depth with full thread depths is to be expected >>>> without broken taps by the pound >> I have not done much 6-32 (Thats the worst thread for major-minor >> diameter ratio). > Little argument there, which probably explains its popularity. I can't > believe how sloppily some electrical hardware goes together. > >> 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? > > 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. > >> 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. Try using roll form taps. They don't generate chips.
Regards, Ken > >> Jon >> >> >> ------------------------------------------------------------------------ >> ------ 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 > > Cheers, Gene ------------------------------------------------------------------------------ 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
