On Sat, 3 May 2014 01:14:36 +0100, you wrote: >On 3 May 2014 00:53, Gene Heskett <ghesk...@wdtv.com> wrote: > >> But in grinding them down, its obvious I wall NOT have a good shoulder >> because the 8mm is just about the bottoms of the ball grooves. > >Rather than grinding, consider trying a CBN insert, and the fastest >spindle speed you can manage. >(Turning with CBN tips is closest to single-point grinding, if the >material isn't red hot and fizzing, you need more spindle speed).
You don't need CBN to turn ballscrews down. I've done dozens of them, ordinary steel cutting carbide inserts work just fine. Just need to take a decent initial cut to get through the hardened surface. Stainless steel type feeds and speeds work fine on the surface layer and once you are through they are quite soft and easy to work. They centre drill easily then you can use the tailstock for support on the long machined and threaded end. I normally put them in the 4 jaw, take 0.25 to 0.5mm off first pass with a CNMG type tool then switch to a DNMG for subsequent passes. Steve Blackmore -- ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available. Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
