On Monday 23 January 2017 03:34:23 Erik Christiansen wrote: > On 22.01.17 11:08, Gene Heskett wrote: > > The faceplate hub looks and measures pretty close to cylindrical, > > but it is a rough surfaced forgeing or cast steel surface I am > > looking at, and I'd druther it was trued, which means I'd have to > > separate it from the chuck and turn it around on the spindle to gain > > access to taking off a thou or 5 while making it cylindrical and > > concentric. > > That'd work, and as ISTR the chuck isn't dead concentric now, not a > lot of precious alignment has to be restored. If I had a screw-on > chuck, then a bit of Murphy-insurance would be my priority too.
I am familiar with that guy, he's even been known to drink my last near beer. I tried to make the alignment plug on the G0704, but a 1/4" carbide bit wasn't rigid enough and a calculated circle, because I was a big dummy and let it do it ccw. was about 20 thou undersized for the first, smaller cut, and rough despite keeping the ditch clean and swimming in buttercutt. Fixtures got in the way, and about 2/3rds thru a one inch block of butter soft alu, I gave up, sawed the remaining ears off and chucked it up in the lathe, trued up the face to about .0015" wibble with a hammer and trued up the diameter till my newest caliper was a slip fit on that, and the hub it represents, then squared up the fillet to the smaller diameter that represents the flange of the spindle. While I was trying to do that, the damned noise was attacking my, giving me false joint errors & shutting me off, and everytime it did, I put another ferrite on a cable, but to no avail. This SPI buss is quicker even than a mesa parport look-a-like such as the 5i25, but while the waveforms look good on a 100MHz analog scope, switching noises from the spindles vfd (Its all opto-isolated except of course the vfd output, and ditto for both motor drivers) and the 2 xz drivers. So I guess, I'll have to drag out my gigahertz digital scope and see if I can get a better handle on the SPI bus and its mistakes. That will take me dragging out some scrap and making a table above the light rail, so I can stand on a stool and probe the buss, up close & personal. > ... > > > Its no biggie to me if I have to chuck up a 1/2" piece of A2, put a > > dial of it and work the chuck over with a dead blow hammer to > > restore its grippers to .0001" runout when I'm done. Its a medium > > priced 3 jaw with 2 piece jaws. I have serious doubts it even has > > the ability to match that if the 1/2" A2 is loosened & retightened. > > But I'll find out in due time... > > Looking for alternatives to assault & battery, the jaws can be ground > while expanded inside a ring, for concentricity in that role, but how > would you grind the inside of jaws clamped on something? Drill a hole > in each jaw when it's closed tight, fit pins, and then grip a ring on > the outside while grinding? No, thats commonly done by putting it in high gear so centrifugal force does the outward push. I can get a bit north of 1400 rpm, until the smoke rolls out of the upper countershaft in the pedestal. I may have the upper belts too tight, but the backs of the belt show wear from striking the front edge of the hole in the pedestal/foot, and I took the tension adjustment up enough to stop that contact. On the spindles bronze bearings, they have enough square inches that bearing heating is maybe 15F, but that 5/8" or 3/4 countershaft, that much tension is apparently pulling it plumb thru the hydrodynamic effects and into metal to metal contact. The heating there is serious, as in 160F or above in a 5 minute runtime. > Pretty good is as good as an affordable self-centering chuck gets, I > figure. And I guess that in use, you'll just perform all turning > operations requiring concentricity in one workholding, so it doesn't > matter if there's a thou or two of eccentricity. Or buy a 4 jaw independent similar to whats on TLM now. I keep a mag base with one of those 30-0-30, .0001" short finger feeler indicators on top of its headstock so its handy. I can usually get a part back to a thou or less with a big cheater pipe on the handle, not so much for the work holding force, but for the fine adjustment it allows. Cheers Erik, 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
