In article , Harold and Susan Vordos says...

In my mind, the purpose of a level is to duplicate the condition in which a
machine tool was manufactured. That does not imply that they use levels in
the process, but allows one to duplicate a condition after the fact. If
you level a bed, it will be in the same plane as when manufactured, at least
in theory. I think both of us would agree that it could lean in any
direction (but remain in a flat plane, regardless of angle) and still
perform as intended. The purpose in leveling is to establish a datum
plane, or point, so one can make relative measurements (or comparisons) with
ease. Machines that are not level make it very difficult because of the
constant compensation for the degree of tilt. Beyond that, I don't see it
as a necessity. In fact, I recall advising one fellow that he could set up
his small lathe at an angle such that he could access it easily from his
wheel chair. So long as the bed is not twisted, it makes no difference
that it leans one way or another. What say you?

I think that is true. I'm just trying to imagine how for example
the south bend beds were made.

First cast, then probably the ways were roughed out on a planer.

At this point there was possibly a level used on the planer bed - but
my guess is they first got the mounting surfaces all in the same
plane, then flipped it over and did the ways. So when you were
done, if the planer bed were level then the part done on the planer
would be also.

Then the bed goes to the scraping department - and there I don't
know if they simply used spotting gages or if they make more
sophisticated tests. I know in the moore book they describe the
use of full length test gages and even more intricate tests like
autocolimators and so on. The implication is that maybe the
level things before they start, but that's only the beginning,
a spirit level even like the starrett master precison on simply
won't come close to giving the accuracy for a machine like that.

Reading between the lines, I get the impression that the south
bends were pretty much Chevys, and something like a moore would
be a deusenberg. g

And that the things the moore folks worried about were even
conceived by the guys at the south bend plant.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================