A lurker here, who bought my ML7 from me has asked a question, and I'm not sure what to advise. Here's his question:
"I recently bought a backplate off RDG on eBay, as I wanted to put the three jaw chuck on my old lathe onto the Myford. It does not fit onto the spindle nose! It does fit the 2MT/Myford adaptor that came with the lathe though.
When I say it does not fit, I mean it does not screw fully onto the spindle to the extent that it does not reach the unthreaded portion of the spindle.
I looked at the spindle and there's a small palce where the thread is very slightly burred. I wonder if I fettled this a little my problem would go away. Do you know if the spindle nose is hardened, and/or what would be the best way of doing this. I've seen the credit-card- sized diamond 'files'. Would one of these be OK used _very_ carefully? Do you think I should try to tap out the threads on backplate (is it 1 1/8 x 12 whitworth? Tracy Tools I guess)?
What puzzles me is that it fits on one thing (the 2MT adaptor) but not on the other (the spindle). Now it seems to me the spindle is likely to be more accurate (though maybe slightly damaged). Maybe the backplate is cut very 'tight'."
The lathe was supplied with a Myford chuck which fits fine, and an adaptor to allow Boxford chucks to be fitted (which also fits fine).
Any ideas? I was going to suggest using some engineer's blue to check the fit, when I realised that my understanding of how to do that is probably iffy, and one of you lot could explain it much better.