Metal lathes have been highly standardized for a long time.
And there are literally dozens of standards to choose from!
There are morse tapers, brown & sharp tapers, threaded spindle
noses, tapered spindle noses ... you can even mix and match
your standards! Most manufacturers do.

Bruce Bourg wrote:
Hi,

How standardized are metal lathes? Admittedly the one machine
shop I use has 4 identical lathes, so I have little sampling.