Lathes on casters

This is confusing two separate steps.

Winding sticks are one way of tackling Step 2, not a substitute for Step 1.

My feeling is two different reasons for levelling have become intertwined and this causes  confusion.

Schlesinger's step 1 is basic engineering best practice. Lathes are designed to operate upright on a flat floor. Consider the lathe as a bridge or girder rather than a machine tool. Its substantial weight is best managed by taking it straight down to ground. If the weight isn't taken straight to ground the frame is likely to twist and the machine might topple over. Builders level and use plumb lines to ensure their walls are true for this reason. Failing to level a tower block or even a garden wall is incompetent. Perhaps less obviously levelling is also necessary when installing any kind of large machine, and the need for level accuracy becomes more important as size and weight rises.

New machines were set-up level by the maker, and could be expected to perform properly if installed level in the same way by the customer. Stage 1 is applied first to the floor, then the stand, and finally to the lathe. Schlesinger emphasizes levelling because he was a professional engineer concerned with getting the best out of large machines, not the tiddlers we own!

Considered as bridges, mini- and other small lathes are stubby and stiff compared with Myfords. They can be plonked on any reasonably flat surface without twisting the bed. Levelling these likely to be a waste of time.

Considered as bridges, Myfords are bendy. Their beds twist making it necessary to take reasonable care installing them. Having a bendy bed isn't all bad, because they can be deliberately bent to improve alignment.

Moving on to Stage 2, all big lathes should be considered bendy. Even monster machines sag under their own weight, and more when loaded. A stiff lathe lightly loaded with small work may be fine, but not if asked to turn something heavy. How much each machine bends varies, but it's best to install on a stiff straight stand supported by a firm flat floor.

One way of correcting alignment in Stage 2 is with a sensitive engineering spirit level, another is the 'Rollies Dad' method, and I suppose 'Winding-sticks' would get close too, at least with a flat-bed lathe. How accurate is aligning by straight-edge and does it work on a prismatic bed? I don't know.

Once a lathe is installed in a fixed position, it doesn't need to be level to turn straight. Within reason they work tilted on ships or in outer-space.

So two related but different reasons for levelling lathes, both potentially optional. It's confusing, especially when 'levelling' is used to mean 'aligning'.

Dave

Edited By SillyOldDuffer on 21/01/2023 13:39:37

My latest inhumane lathe experiment is a castored and aligned mixture of a 180*300 and a 210*400 lathe with a homemade 48mm hole spindle.

Target was to make a potent lathe where all parts can be handled by a reasonably fit 77 year old.The stone is a borderline case

Google NU210E auto for my next  journey to lathe land

Edited By Niels Abildgaard on 22/01/2023 11:31:55

That's quite a slab of granite there Niels. I am sure you don't get much bed twist there. Could be a bit top heavy though? 48mm through hole sounds pretty handy. i wish I could do that on my Myford.

The 5£ second hand shop under-thing is 550mm wide and can easily pass a 770mm dor opening.

It has not felt dangerous and unstable ,but my very nice appartment has no dor steps.

A picture in sligthly better resolution can be seen here

Indor oilfield lathe

Edited By Niels Abildgaard on 22/01/2023 15:51:31

Edited By Niels Abildgaard on 22/01/2023 15:53:08

Niels Abildgaard:

Out of curiosity:

What was the original use of the second-hand stone?

What is the 21.8mm dimension?

More power to your inhumanity to lathes!

Hello ega

Stone is one of a pair that worshipped a central,bigger tombstone with doves and angels.

I pass the unused twin every day with dog.

Cost was 1 kg instantcoffee and some chokolate.

21.8mm is measure from top of compound slide to centreline within plus minus 0.01mm.

Glad You do not disapprove lathe harming.