(06-04-2014, 10:08 AM)Micktoon Wrote: ..... Or to make a special parting tool so it could part away the very end section of the backplate nearest to the spindle shoulder yet miss the spindle by a thou or two, I could also make the tool so it could not go in too deep and mark the spindle as I have a smaller spare backplate with the exact same register to measure.
Any help most appreciated
Cheers Mick
Mick, I'm afraid I have no unearthly idea why your chuck would become so stuck like that. I can say that I've used a parting tool in that way to remove rifle barrels that were over-torqued onto their receivers. They let loose with a bang sometimes when the tool breaks through, and then the barrel can almost be unscrewed by hand. I agree with you and would consider that a last resort however.
Just thinking out loud here..... But what if you tried chucking up a good size piece of steel bar in the lathe, and tried bump knurling it at slow speed with the spindle running in reverse? Maybe the side pressure on the chuck/backing plate combined with the reversed rotation might coax it to come loose? Just an (amateur) thought.
That is one beautiful looking lathe by the way! Best of luck to you.
Willie