On Sunday 14 January 2018 17:10:05 Chris Albertson wrote: > If you buy the collets on eBay and you measure them, if they are out > of spec you can return them as "not as described" and then seller is > obligated to pay for the return postage. You will get a prepaid > shipping label. Many times sellers don't want to pay to return ship a > bad part, after all what would they do with it? So they jut resend a > replacement. It's a hassle to have to wait twice for you order but > the up side is you might find a use for th defective parts they let > you keep. > > I have four parts being replaced to me right now, One is a precision > 8mm stainless bar that has rider marks on it and a linear > recirculating ball bearing set that ha loose ball in the package. > They are seeing replacements. > > eBay is very safe this way. If the seller does not handle the problem > eBay can reverse the transaction and pull money out of the sellers > account. > > So buy the Chinese part but make sure there is a spec on the web page > and measure it after you unpack it Most of the stuff is very good, > better then spec'd But I did just get some defective parts > This is a part that hard to measure. The 50mm x1.5 threads have enough clearance that the nut falls from one side to the other of the threads clearance, giving you false high runout measurements, so chucking up a ground rod, putting the tension on the threads is about the only way to test it. I have some soft A2 thats centerless ground, but its someplace in the midden heap, stuck in a cardboard shipper tube, but I haven't seen it in 2 or 3 months. When the new ball bearing nut arrives, along with its wrench, I'll uncover it and use that to measure things with.
Then at some point I need to make a ring to fit the drawtube outside thruster pipe to center it in the left end of the spindle. As is, it wobbles about 1/8" and the weight of the hand wheel out on the end of it, limits the rpms to about 100 else it sets up a shake. Lots of little piddly things to fine tune yet. I was rather pleasantly surprised that the alu jig I made to hold that grizzly part worked so well. Remember I started out with about 7 thou of runout in the mouth of the spindle, which tells me it had a case of whiplash from the same fallover that wrecked the compound, long before I paid way too much for it. So my first operation to correct that was grinding a new mt5 in the spindle bore. OTOH, expertise and experience like this has never been free. :-( [...] 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
