On Wednesday 07 March 2018 02:38:37 Marcus Bowman wrote: > On 7 Mar 2018, at 06:28, Erik Christiansen wrote: > > On 07.03.18 00:58, Gene Heskett wrote: > >> And the grub screws stayed tight? > > I made a whole tapping system for my pillar tool, for small taps, > using the 4-grubscrew technique, and I have used it successfully for > years. I only use it for threads below M3, though, and only for manual > tapping. One flaw is that although the grubscrews stay fairly tight, > most of the time, they do have a tendency to work loose because of the > angle of the twisting force, which is roughly parallel to the flat of > the squares, at the tangent point of the imaginary same-diameter > circle. Another more annoying problem is that there is nothing much to > stop the tap from tending to slip along its long axis, as the screws > slacken slightly. What they need is a conical hole, a vee or a flat > with shoulders ground into the shank, to stop the sliding. For larger > taps, that would be easier to arrange, but I suspect the forces > involved with those larger taps would tend to magnify the problems. > > Is the answer not to use a thread mill? Expensive - yes - but more > controllable and easier to cut the thread in several passes, I think. > I've no experience, except of looking at my shockingly expensive > thread mill cutter and wondering about its life expectancy. > > > Marcus > I actually have one of those, bought in my younger and dumber days. But its never been used as its 3/4" OD. Minimum practical hole would be at least 1.5". In HSS, life would be what, 4 tapped holes in clean steel? I might use it someday, if I ever need to tap for a >1.5" bolt... I can't imagine using it for anything but a monster woodworking vices nut. > > ---------------------------------------------------------------------- >-------- 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
-- 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
