On Tuesday 08 May 2018 22:19:25 Jon Elson wrote: > On 05/08/2018 06:57 PM, John Dammeyer wrote: > > I had a brake disk surface ground so it can be laid on the mill > > table and a dial indicator swept around without jamming into the > > T-Slots. For the work I've done to date it's been adequate. It > > fits on my surface plate so I could scrape it even flatter and maybe > > someday it will move up to project #42. > > I have a program that generates a full circular arc, and > then goes to the center of the arc. > So, I can mill a path around the circle, then swap the end > mill for a dial test indicator, and sweep the > circle. So, I can tram the head to the actual X-Y plane of > motion, not just the surface of the table. > And, in fact, due to wear, I get a little bit of a saddle > shape there. But, you can set the tram to > get the best average of the X-X and Y-Y deviations. > > Jon > And that, Jon, is the best idea yet. I assume you can adjust the diameter so as to re-use the milled plate again for the next time? What I've been doing is to chuck a piece of A2 rod, mag place an indicator rigging to the table so as to touch rods bottom in the x direction, then fiddle with the collet until its running reasonably true, then move it up to the middle of the rods length, still touching it in the x direction. Then raise and lower the head while tapping it one way or the other until it moves with a minimum motion as its run up and down the post. Its at least usably aligned with the direction of motion...
This is far from perfect as its still off in the y direction, a fat 10 thou an inch and quite likely in the x too because the post is bolted onto the base and would need more precise machining to square that up. This will not detect a post leaning in the x direction, only that the up-down motion is aligned along the spindles axis as it runs. But its at least not drilling too eggshaped a hole because the motion is not aligned with the axis of the spindle. Cleaning that up is a somewhat lower number in the line than #42 though. At my age, I might not make it to #42. -- 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
