You should first set the lathe to cut parallel without any tailstock support. Only then would you adjust the tailstock for parallel cutting.

Bed likely needs setting level (without twist).

Edited By not done it yet on 22/02/2021 11:00:51

Is it possible that the bed is twisted because of the manner in which the lathe is bolted down?

Well worth checking before disturbing the Headstock

It is taken as read that all bearings and gib adjustments are correct so that Top Slide, Cross Slide and Saddle are not slopping about.

To check for twist and to correct it, look at Ian Bradley's "Amateurs Workshop" or his "Myford 7 Series Manual".

By machining an unsupported bar to a collar at each end, like a cotton reel with wide flanges, the diameters at each end will indicate where adjustment is needed.

This is sometimes called "Rollies Dad's Method".
It will be time well spent!

When the bed is free from twist, then use, or make, and alignment bar.

Unsupported it will tell if the Headstock IS out of line.

If it is not, leave well alone and start checking with the bar between centres, to adjust the Tailstock into alignment

Making adjustments in the wrong order could make matters worse rather than better

Howard

I have a Boxford ME10. It came with screw adjusters built into the feet, a 1/2" Whit thread. In my experience you cannot hope for the lathe to turn parallel without using these.