Paul,
I am so sorry, I looked through the posts above and realised that I had not mentioned this. I thought that I had !!
You try to help people and they mess you around like this ! My fault totally !!!!!!!!!!!!!!!!
My record power chuck is in fact a vicmark that RP. sold a while ago, ( they told me today ) this had an adapter ( home made, not by me ) to fit onto a 1" x 8tpi. spindle. This was so jammed on that it was impossible to get off, I have got it off after a year of trying...........few. The chuck itself is 3/4 x 16 tpi. I had an old 3/4 x 16 tpi adapter, that I tried on the spindle and in the screw on drive. Did I make any sense at all here ???
This mistake, on my behalf, has confused matters and I am very sorry for that. I am now sat in the corner chastising myself with a wet Kipper.......sorry.