My Chester Craftsman lathe has a similar problem, seems to be too much clearance between the parts.

I drilled and tapped to fit three screws, one on top and one each side to take up the play. Not ideal, but it helped.

I think the real answer is to rebore the the tailstock and make a new spindle. It,s not a very good design, perhaps if the tailstock was split and clamped it might work better.

A pet hate of Tony at lathes.co.uk but I see what you mean!

Windy:

Does the moly combine in some way with the treated metal?

Myfords changed the design of the Super Seven tailstock to avoid this lift problem.

It's many years ago now, but I remember Anthony Mount bought a new Warco BH600 lathe which he was pleased with, but just did a few tweaks to it, or fine tuning as I vaguely remember he called it.

I seem to remember he commented that the tailstock quill was a good fit in the casting, and I think he made a collar to fit over the quill and screw to the face of the casting but this was just to house a seal.

So if your quill is a sloppy fit in the tailstock bore, and it is the bore that is worn or it's all just a slightly sloppy fit from new, you could machine a thick collar that is a close sliding fit over the quill and secure it with screws and maybe dowels to the end face of the casting, assuming the end face is machined flat and square to the bore. The clamping method that your tailstock has wouldn't then matter or cause a problem if there is no clearance around the quill.

I have a 16 year old large Warco 1330 lathe with a tailstock quill that is a firm push fit in the honed bore of the casting, just like my old Boxfored lathe, with no play at all. The quill on my Warco lathe is clamped by a Bronze bush either side of the bottom of the quill that are pulled together by a lever, the radiused ends of the bushes then clamp the quill firmly. This is a common method used on lathes but even this would still deflect the quill if it were a sloppy fit in the casting.

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That form of clamping only causes problems if the two parts don't fit together well.

The Smart & Brown model A uses half of that system which would certainly lift if there was slop. The drill mill and the Tom Senior light vertical use an exact replica on their quills, and I have tested them both. Using an optical sight in the spindle focussed on a target mark, I tightened up the locks and there was no noticeable movement in either mill. The line spacing is 0.025mm, and movement of a tenth of that is visible.

Wild idea … maybe not for Windy, but for the back-burner:

Put an ER Collet on the nose of the tailstock body.

MichaelG.