"Jim Wilkins" wrote in message
...
On Nov 24, 1:24 am, "RogerN" wrote:

A lathe can make another lathe, but a mill can not make another mill. No
CNC's allowed.

What part of a mill can't a mill make? How do you machine a lathe bed in a
lathe?

I think the idea is to remove the head and tailstock and use a tool
bit in the carriage to plane the ways. You might want to hang the new
lathe bed upside down over the old one so you can plane all the way
surfaces parallel.

When I needed to remachine a worn lathe bed I used a large horizontal
milling machine.

I recall some drawings that I saw in the '70s, at _American Machinist_, that
illustrated the self-replicating nature of the lathe. It was a hypothetical
machine, with many components machined flat and/or bored on the faceplate
and with cylindrical ways, like a chucker (American Lathe?) that gained some
interest around 1978 - 1980 or so. There also were very small lathes,
typically types of specialized screw machines, made that way in the early
part of the last century.

Some of the very earliest screw-cutting lathes, maybe even Maudslay's
machine, had a V-way in front and a flat bedway in the back. The idea behind
that was that the V-way didn't require perfect straightness; slight
compensations could be made by filing or scraping the flat way to
compensate, effectively tilting the cross slide up or down a bit. It always
seemed to me that this would help only at one diameter of work, but that's
the way it was done, and many of them were made by hand before planers were
in common use for the purpose. The idea of the self-replicating lathe may
have included an assumption that some of the work was done by hand.

In any case, the running parts of a lathe depend upon round journals and
bushings, and most parts can be made that way either for running or for
locating, so the lathe was the most capable of self-replication.

--
Ed Huntress