On Tuesday 01 August 2017 23:26:31 Ken Strauss wrote: > Have you considered using a larger tap drill? A lesser thread depth > makes a huge reduction in the required tapping torque without > significantly reducing the holding power. Some references > (http://www.tapmatic.com/tapping_questions_torque_vs_thread_strength.y >dev for example) show that a 50% thread requires less than 30% of the > torque needed to cut a 75% thread. > I think I was shooting for an 85+% thread because the bolts are brass and the engagement is only 2.5 to 3 threads deep in that pipe wall. In this case I hit it pretty close as the end of the bolt was an interference fit since it was bigger as it got further from the chuck jaws. Next time I may try to use the G33 because one can make a compensating taper with it, but not the leadin or out while maintaining thread synch. G76 needs to be able to taper the drive line. But I haven't found a way to achieve that. Best I could do with a G33 would be a g0 speed backout at the end, but it wouldn't be a synchronized backout. I may see if thats a suitable solution next time I need to make such bolts. That may be the guard screws, which are 1/4" steel, but not 28 tpi, the darned things are 30 tpi! If I decide to get one of the Boyds VT stocks, I'll take advantage of the flat belly and redo the front of the floor-plate/trigger guard by removing the OEM steel under it welded up to be flat face now. A couple ounces of welded up steel the was added to flatten it, removing the OEM belly bump, welding some flaws to fill them in, and remachining it dead flat and possibly a bit narrower before I start putting it to bed in the new wood. In either event, its pillar bedded now, and will be when I am done.
But this is nice to know the next time I tap for steel bolts, thanks Ken. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
