Jess wrote:

I've got this neat old steady rest, and I've had it for years, without
ever knowing what it originally fit, and well, was hoping to get some
help with its identification from some of you old (and / or new) hands
here in the group.

Here is the link to a picture and some dimensions / details. No spam
at this link, just info. on the rest.

http://www.indiancreekprecision.com/steadyrest.html

I believe it would fit a lathe with a swing of 16".
Its a very well made, heavy and rigid rest, I wish all steadies were
made this way. I love the adjusters on this thing.

I have thought about copying this pattern to make a 'jr' version of it
for my smaller lathe.

If you are careful to provide the dimensions you have already measured, then you
shouldn't have any trouble selling it e.g. on ebay. It would be nice to
mention whether the castings are iron or aluminum. You're going to need some
luck to find out what lathe that came off of. If the castings are aluminum then
I bet it came off an import, the way those adjusters work. - GWE