Joe,
Over at alt.binaries.pictures.woodworking, you wrote:
"I will be making some Tees to mount 3 vises, the belt sander, and who
knows what else on that can just drop into the bench vise when needed."
What you described sounds like a "handy notion". Can you describe these
"Tees" to me (maybe I'm the only one who doesn't know what a Tee is)?
Thank you,
Bill

Sure Bill.
I got the idea from a Woodsmith shop video and posted it for
you on 5/4. You must have missed it. I will repost the
picture, ATTN: you. Hoooooo, boy.
Say you want a vise to use for the occasional metal project, but
don't need it often enough to dedicate bench space to it.
Mount it on a small 'platform' that has a vertical piece of plywood
attached underneath (why I call it a 'T') sized to fit into your vise
(remember the screw and rails underneath). Keep it stored wherever
until you need it, then open your woodworking vise a couple of turns,
drop it in and there's a stable metal vise. Same with a belt sander.
Most have a couple of unexplained notches on the handle. Make
your T, add a couple of bolts or screws to fit the notches, stick it in
the vise, and lock down the trigger. It can also be done vertically.
You can add a couple of blocks or triangles underneath for support
if you want. 1/2" ply works - the thicker the less tippy it is, but
don't go overboard. The idea is stable, but quick and cheap.

My scroll saw and grinder are both done with the same thought -
stable when using them, but I can take them off the bench when
I need the room. They're just bolted onto scrap ply pieces (as of today !!).
They could be clamped to the bench, but with a piece of carpet
padding underneath, they don't move at all.

That's one reason I wanted two shelves under the bench, even though
some stuff will live on the bench, I've got a place for it when I need to.
-J