I assume this 10" shaft extension runs in a support bearing of some description ? because if not you really are fighting an uphill battle !
Right, now for the lecture, If you've gone to all the trouble to buy a lathe then at least spend some time installing it and aligning it before trying to use it ! And whats all this crap about waiting until you can afford a milling machine ? There's no point in having a machine that you cant go and switch on and use with some degree of accuracy is there ?
And finally you show up as living in the North East there are some very very experienced machinists on this Forum who are local to you why dont you try PMing them and see if they can come and offer some advice it would be a dam sight easier than the rest of us trying to guess what you've got and what you've done
RANT OVER !
Good Luck !
Mike
I think you're right about the support bearing. It's something i've been thinking about.

The spindle fits through the hole in that mounting block. This assembly is held vertically, it's part of a spindle sander i'm building, and the motor slides back and forth along the rods constantly. Despite taking care in laying it out, the hole is off by a small amount so i'd have to turn a bushing eccentric. Or make it an undersized top hat and fill the space with epoxy.
As for the lathe, it's one of many things i've needed to 'fix' but I tend to leave problems until I really need them fixed. I haven't required the lathe to be that accurate until now. I've got so many things I could and probably should improve on that i'd never find time for anything else if I really started pursuing them.
Plus those machinists in the north east have their own things to worry about. I don't want to impose on them, but with a thread like this people are free to answer or ignore it as they see fit. (and by the end of the day i'd like to solve these problems as much on my own as possible.)
As a sort of reply to Mikes comments. Sadly, I have only had a couple of evenings off since March. Wife had hip op. It went wrong- injections and paralysed. Now it is cataracts for her as well. I can scribble a few words of possibly constructive advice.
Sorry to hear that about your wife. Old age isn't treating my grandma very well either, but it always seems like it's harder on my grandad than her.
But don't feel you have to come over and fix my problems for me.
Since it sounds like you got stiffed by Chronos, I'd give 'em a call - be all nice about it, but basically try to get them to at least take the thing in to have a good look at it. As they are in stiff competiton with RDG, Arc Euro & Gloster (at the very least), getting a bad rep is the last thing they want...
It was a couple of years ago now and i've never been a big fan of returning items. It's a big hassle, they make you pay the postage, and then there's no guarentee the replacement will be any better.
I wish I knew of some second hand tool shops. You never find anything in the yellow pages, or their website, so the only way to find out is by word of mouth or just stumbling on them.