On Saturday 04 November 2017 06:38:43 andy pugh wrote: > On 4 November 2017 at 00:22, Gene Heskett <[email protected]> wrote: > > Now I know why Shars is considered to be the costo version of > > machine tooling. I am still trimming the register diameter, but so > > far only 2 surfaces have escaped a cutting tool, the OD, which > > doesn't touch anything, and the threads. Everything else either > > wobbled, or was eccentric. > > Are you sure that it is mounted correctly on the thread and the > register? It seems to me that you would have to _try_ to make a > backplate wobble relative to the thread as they are probably all done > in one setup. > > Before you commit too far, have you tried unmounting and mounting it > to see if it goes back repeatedly?
Yes. P now understand that when screwing it on backwards to do the work on its back, that its running into the end of the threads on the spindle probably held it off kilter a bit. Fineing up the bore that fits the cylindrical portion of the spindle so it would screw on all the way whew n turned around to the correct side, and cleaning up the wobble, I note there is a very small eccentricity of the hub when turned correctly, but at the same time, the back face wobble is not visible, so it was forced out of kilter a hair by the wedging against the end of the teeth of the spindle thread. This likely means that when I refaced the rear of the bub, the face isn't dead on. But it didn't take much to clean up the front face, certainly less than 30 thou at the rim when screwed on solid. The supplied register was about 3/8" larger than the pocket in the rear face of the chuck and required quite a bit of trimming to get down to where I can feel it riding the chamfer, so another thou, maybe as much as 2, and it should fit the chuck. But when bolted together, I am going to have to make a sled to fit the ways as its about all I can do to hold it up for a test fit. That guy that could in his 20;s, pick up 250 lbs and carry it all over town, he doesn't exist anymore. Dammit. The intention is to drive it together, put witness marks on it, then drill & tap the new bolt holes to make the final assembly. Its tempting to turn it back around and make the rear 5/8" of the hub the same size as the rear of the hub on the 6.5" 3 jaw, as it would save me some time making a second clamp ring assembly that fits over the hub and joins it solidly to the spindle flange to prevent its coming unscrewed when doing a G33.1. If I had a piece of pipe the right size to make a spacer to stop it from hitting the end of the thread when reverse mounted, that would probably make it run a little truer when mounted backwards as it would assure its self centered on the threads. But I don't have a pipe the right size. Then I could clean up the back face of the hub while turning it down to work with the clamp ring assemble I've already made. It hasn't slipped yet on a g33.1 and if I set the vfd to be downright brutal, it can reverse at 200 rpms in under a second with the lighter 6.5" chuck mounted. Drive belts yelp though. :) Not much use of that, and it may encourage some slippage of the top drive pulley on its worn shaft, which now has a taper hub to lock it in place. Some idiot in its nearly 70 year history put the top drive pulley on backwards while replacing the dual spindle drive belts, and that missed the keyways entirely, so the setscrew was pulled up to what he thought was tight enough to drive it, but all that did was chew up the shaft and of course the wear as it slipped put a few thou of forever wobble in the pulley bore. Well hardened shaft so it was the pulley bore that suffered the major fraction of the resultant wear. That was bored away to make room for the shop made taper hub, so it runs pretty decently straight now. All that was done on TLM. All this was found when I discovered my drawings showed torrington needle bearings in the shaft yoke that were actually bronze bushings. Between that of the heat from the pulley slippage was so bad it would start to bind the shaft and slow the spindle down if I ran it for long enough to cut a lathe pawn out of air. So the cover on the end of the cabinet was drilled loose, the shaft pulled out thru the hole, and I made a driver to push the bronze ones out and the torringtons back in. That lowered the yoke temps about 200F when the spindle had been turning 1k revs for about 5 minutes. The lower shaft did not suffer from excess heating, so the bronze bushings are still in that yoke. IR thermometers are handy, like sliced bread or bottled beer. :) 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
