If you are using it as a probe, why not put the drill in the chuck backward, then you have a precision rod, not a drill.
Spinning seems like an interesting idea, moving fraction is always less than static friction. You would likely need to spin a 3mm rod fast enough so that the tangential speed is comparable to the up and down speed. Let's see,… spinning a 3mm drill at 60 RPM, one rev per second you have 3 * 3.14 mm. per second tangent speed. That is something close to 9mm/sec. that might be too fast, I don’t know Even if used “point down”. My guess is is that you want the tangent speed comparable to the Z-speed. I use those very cheap 2, 3 and 4mm drillig for 3D printed plastic to ream the holes if they print undersized. The cheapest Aliexpress drills I can find are good enough. Good that you have found another use for them. The diameters are spot-on, or as good as I can measure. Is the coating on the bit electrically conductive? I know some oxides don’t conduct electricity. > On Mar 15, 2024, at 7:52 AM, gene heskett <ghesk...@shentel.net> wrote: > > I have obtained a 10 pack of uxcel 3mm mills. Look more like a rasp than a > normal spiral mill. 2 edges on the plunge face though. > > They will be used as both the probe signal generator to find the 3mm holes > for bolts in a 9mm wide linear bearing rail. That means they will have maybe > .2mm total clearance when inserted into the 3mm hole in the rail to reach the > bottom of the hole. When functioning as the probe contact I'm spinning them > in reverse, so if they do touch, tripping the probe, they should skip w/o > cutting because they are turning backwards. I intend to do the usual 4 corner > search when locating the hole, but once found, I'll g38.2 Z deep enough to > reach the cf tube, reverse the direction to fwd, and run it down several mm > thru the cf and stroke it up and down to clear as much of the cf from the > hole as possible. > > What I need is a good idea of an rpm and feed rate that will not wear the > edge from too slow. > > What revs and feed rate stands a chance of doing a decent job of making a > clean hole w/o excess tool wear? Max revs about 2750/minute. > > Thanks all. > > Cheers, Gene Heskett, CET. > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
