As Pete says, we were discussing ways of securing lathe bed to bench.
1 - our small lathes are very light, our benches are often not as solid as they should be and workshop floor is often flimsy timber. However much effort you out into securing the lathe without distorting it, it is often all in vain because everything moves, twists and distorts.
2 - all the lathes with more than three fixing points - by default it is difficult to achieve flat plane that avoids distortion. If you have one fixing point (like on watchmakers lathe with pedestal under headstock) you cannot distort it by fixing to bench. Similarly with two fixing points (again mostly small lathes) you are not twisting the bed (as long as you discount the width of the pedestals). With three fixing points - you achieve flat plane by default. And yet most of the lathes have at least four and often more bolt downs.
3 - however carefully you adjust all the multitude of legs/fixing points, unless you leave one end of the bed free, you will be affected by thermal expansion distorting the bed fixed rigidly to bench
Solutions:
Some people fix the lathe to something substantially stronger and heavier than the lathe (eg granite block).
I was in turn extolling virtues of the idea used by Hardinge in their HLV-H lathe. Three point support (two under headstock, one under tailstock), tailstock end allowed to expand as well as preventing bed from twisting (single point). All three points sprung loaded. One could adapt similar idea (using intermediate plates between lathe and bench) to our little lathes.
Advantage of this arrangement - it is impervious to flimsy floor, weak bench, not affected by thermal distortion and not bothered by owners adjustment.
Chris
ps mine is
Prazimat DLZ
