On Friday 15 July 2016 21:50:37 rayj wrote: > You might try cutting in something softer, nylon or maybe machinable > wax. Probably wouldn't break the chip if things go wrong. > > Raymond Julian > Kettle River, MN
Thats a thought. A major portion of the problem in this instance is that I would like to keep the fingers that are to be squeezed down onto the ball screw end by this tapered thread and similarly tapered nut bore, is that by the time I have expanded the thread to where my boring tools will actually do the job, the wall thickness is so great that much of the squeeze the tapered nut and thread are applying is being wasted in bending the roots of each "finger". The bore for the butt of the screw is about 9.13mm if I want the screw to fit precisely enough that the nut can compress the socket after I cut 2 or 3 cross slots so it is flexible enough to grab the screw. Ideally, an internal flex point to increase the flexability of the gripping fingers or leaves would help, or a similar groove machined at the root of the slots to serve as a stress concentrator and allowing the A2 shafting fingers to spring or bend easier could be done. As this nut etc on the end of it will restrict the outward motion of the crossfeed by however much length it occupies, I'd like this fat part to not be more than than the thickness of a grade 8 3/8's nut plus another 1/4" occupied by wrench flats". The required flex is constrained by how precisely I can bore the socket to fit the screw, every thou of slop I bore oversize is tonnage of pressure on the nut. The A2 is easier to machine than the nut, I believe because the small bore is causing undercut interference on the bottom of the chip in my smallest bar (which is actually my biggest bar as its a 5/16" boring bar laid in a groove in the side of a 3/4" bar, sitting in a bar holder clamp I made years ago) and I may have to do the final nut boring with a 1/4" carbide mill. That would be done more precisely if I had a 1/4" sleeve for a QC boring bar holder. How well I could make one of those for a bar holder bored for 1/2" bars remains to be seen. Good tooling for one of these tabletop machines is more often than not patented by Rube Goldberg. :) Because the donor steel is 1/2" A2, and the extension needs to be .375" OD with a key groove about .192" wide cut into it, and its got to be at least 3.5" long, this does not portend to be an afternoons job. I can rig a ball bearing tailstock, but with the lack of precision in jacking the tailstock on this POS into usable alignment (its off vertically too), I'll probably have to write gcode to correct it while doing the finish grind with a dremel in the toolpost. Take the .500 down to about .400", then grind the final fit to .3750". Fun and games, not. 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> ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports.http://sdm.link/zohodev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
