I can't see how lathe alignment could affect your angle. If you turned the OD running forwards with the cutting tool in front and bored the ID running in reverse with the cutting tool in back, then yes. But if both were done with the spindle going forward then the tip of the cutting tool is in exactly the same place and should be moving at exactly the same angle.
I must say that if I was doing this I probably would program both the ID and OD tapers _exactly_ the same, even if that means one of them is longer than necessary and wastes a bit of time cutting air. When you change the Z length you leave room for errors to creep in. I suspect that delta-x divided by delta-z is not the same in your ID program vs. your OD program. On Tue, Mar 28, 2017, at 09:54 AM, Gene Heskett wrote: > On Monday 27 March 2017 03:56:53 Gene Heskett wrote: > > > On Monday 27 March 2017 00:17:19 Erik Christiansen wrote: > > > On 26.03.17 18:53, Gene Heskett wrote: > > > > But is 7 the correct factor? It should be fairly easy to jack it > > > > back out. > > > > > > Gene, I've never made one of them, but looking here: > > > > > > http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ve > > >d= > > > 0ahUKEwiE6q-q5PXSAhWGKWMKHeZIAf0QFgg-MAc&url=http%3A%2F%2Funiversalb > > >ear > > > ings.com.au%2Fdownload-subproducts%2Ftaperlock-bushes&usg=AFQjCNGOFI > > >vAU jPQ1JccxaHkdEjC0hT5oA > > > > > > the first bush in the table seems to be: > > > > > > atan((35.2 - 33.7)/11.1) = 7.7° included, near as dammit. > > > So I did the taper turn at TAN[7.7]*total z len which was 0.735" > > Finished (except for jacking holes) hub looks great. Set it aside for > now. > > Chuck pulley and hammer around for concentricity etc, spins good and > true. Edit code to do the tapered bore, but change for a full inch of Z > motion, so I used the TAN[7.7] raw as the inner factor to sub from the > bore at z left end. Using one of those cheap $20 a kit of cemented > carbide boring bars. Re-shapened with a diamond disk in a dremel. Get it > bored big enough (and bore looks like shit, tool is skipping) to start > checking fit using the hub I just made at what was supposed to be the > same angle. Bored angle too steep by quite a bit. Hub goes in about > half way, jams on tip of hub and can be rocked around. Its not trashed > yet, but this is where I start fiddling with bar sharpening angles, > widening the hole at the deep end until it fits. And changing the bar to > a monster I made years ago, a 5/8" diameter bar about 10" long I had > made a groove in the side of to hold a small bar that seriously needed > some stiffening. Takes std diamond pattern chips. Then gradually reduce > the x decrement until it fits. > > I don't believe the spindle head on this lathe has ever aligned with the > z motion of the carriage. I replaced the whole head a year ago after > refitting a new head with all metal gears, and while I cleaned the paint > overspray off the mating surfaces on its bottom, I think this one is > sitting even more out of alignment. At one time years ago I had wasted a > piece of cold roll and a few days adding an offset per inch factor to x > until it was turning a decent cylinder, and should have painted it on > the monitor, as its in the area of 7 thou per inch, but that was on the > OEM head assembly. Cheap, mumble mumble, Chinese crap. > > Andway, change the bar to the big boy, then start shaving the angle is > todays project. After I go to the store and get stuff for breakfast and > fix it for us. > > > Cheers, Gene Heskett > > > 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 -- John Kasunich jmkasun...@fastmail.fm ------------------------------------------------------------------------------ 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
