I've got a project that needs to be indexed to drill a bunch of holes. Its
3D part of course so part of the initial machining is to leave it
"mountable." I have an idea worked out, but it has to be supported at both
ends. I was thinking two cheap spindexers face to face would work. The
work piece is machined with a radius slot in each end that can be clamped to
a pin mounted in each spindexer. Yes, I know. You all have a better way,
but this is the way I am going to do it.

Now once you learn a trick you are sure to want to do it again.

I can clamp the two spindexers to the table with a lathe truing bar between
them, and get them dialed in straight to the machine I am pretty sure. It
will just be tedious and time consuming, but after I figure out how to deal
with any flex in the setup it shouldn't be much worse than truing up a vise.
Should be able to get within a half thousandths over its length.

That's fine for one job, but I'm making a single prototype piece. I'll want
to get the indexers off the table and out of the way when its done. Of
course if the customer likes the prototype I'll be making a bunch of them
over time. So I'll need to throw them on the table and take them off
regularly. I have enough clearance on my knee mill I could mount them in my
vises.

No comes the problem. They will need to be re-indexed to the machine every
time they are used. The front and the bottom are the only reference
surfaces. The sides of the base appear to be as cast. I looked at the
slight step up to Phase II indexers, but they don't look to be any better.
In fact to find an indexer with more good reference surfaces the price jump
is substantial. Well the quality of the indexers is much better too, but to
much for the prototype part they will be used to produce. I'd like to
mill off the sides of the base so they are square and perpendicular... not
to hard... but also equidistant from the center line of the indexing body in
a mirror relationship to its counterpart... I have no clue... , so I could
just drop them in the stepped jaws of the mill vises when I need them.

Actually I just had an idea. Cut the minimum to square up the base. Flip
and mount. Mount a work piece in each. Measure the offset. Remove the
offset from opposite sides of each base. This thought JUST came to me, so I
am sure there has to be something wrong with the idea. Hit me.

Flame suit on.