On Tuesday, February 14, 2012 07:54:16 PM Mark Cason did opine: > On 02/14/2012 03:35 PM, andy pugh wrote: > > On 14 February 2012 18:09, Jon Elson<[email protected]> wrote: > >> For the best finish, of course, you can grind it after the roughing > >> pass. > > > > Hard-turning with CBN is basically single-point grinding. The finish > > tends to be excellent. > > https://picasaweb.google.com/lh/photo/ajPl1y4hNjLTSUjmdbzQUdMTjNZETYmy > > PJy0liipFm0?feat=directlink (The bottom one). It would be better with > > a real lathe, that was with Chinese Junk. > > Andy, what type of steel is that, that is pretty close to the finish > I'm looking for. I have a 2 - CNGA433 PCBN KB5625's on order. I > couldn't pass up 2 for $5.00. > > Also, I found a insert selector on Kennametal's site: > http://www.kennametal.com/en/kenna_perfect/kenna_perf_select.jhtml > > It listed the KB5625 as a general finishing bit. I can also get the > KD050 if I find I need a finer finish, but at about $30.00 - $45.00 > each, I'll hang off a bit, and see if I need it. > > This is just a simple prototype, using available material, but it is > also a educational process, as I tried turning off a seized, and welded > bearing race, but none of my carbide tooling would make much more than a > few tiny cuts in it, before they were destroyed. I'm assuming that CBN, > or PCD inserts would be the only way to turn it off? (And yes, I tried > the grind, and chisel thing first.. all I did was make a mess, and break > a chisel.)
Mark, this sounds like if it was my problem, I would see if I could glue up a plastic container the bolt could pass thru the sides of without heavy leakage as it was supported between a rotary table and its tail stock, so the container could be filled to 1/4" above the bolts top surface with shop heater K2, then get out your EDM power supply, rig some method to insulate an electrode to the spindle, hook the hot side of the edm supply to the electrode and start the table turning while the spindle was fed at about .01/minute & turning 100 rpm or so, and edm it till it could be jarred or cracked loose as a very thin remaining piece & removed that way. You will use up the electrode faster than the steel race, and probably need to change the K2 several times. If you still have an x table drive, feed it back and forth the length of the bearing races width at about 1 minute feed rates. I've had good results connecting to the electrode with a piece of 12 ga stranded, with the strands divided and twisted back together after passing around the electrode, no sparking there at all in what I've done. The copper has enough springback to make a decent connection while the electrode tubing, brass in my case, was spinning inside the loop at 1 or 2 hundred revs. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> There's a whole WORLD in a mud puddle! -- Doug Clifford ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
