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 ------------------------------------------------------------------------------ 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
