On 13/11/17 19:44, Bob La Londe wrote:
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."Â* I have an idea worked out, but it has to be supported at
both ends.Â* I was thinking two cheap spindexers face to face would
work.Â* The work piece is machined with a radius slot in each end that
can be clamped to a pin mounted in each spindexer.Â* Yes, I know.Â* 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 theÂ* machine I am
pretty sure.Â* 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.Â* Of course if the customer likes the prototype I'll be making a
bunch of them over time.Â* So I'll need to throw them on the table and
take them off regularly.Â* I have enough clearance on my knee mill I
could mount them in my vises.

No comes the problem.Â* They will need to be re-indexed to the machine
every time they are used.Â* The front and the bottom are the only
reference surfaces.Â*Â* The sides of the base appear to be as cast.Â* 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.Â* Well the quality of the
indexers is much better too, but to much for the prototype part they
will be used to produce.Â*Â*Â* 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.Â* Cut the minimum to square up the base.Â*
Flip and mount.Â* Mount a work piece in each.Â* Measure the offset.Â*
Remove the offset from opposite sides of each base.Â* This thought JUST
came to me, so I am sure there has to be something wrong with the
idea.Â* Hit me.

Flame suit on.

The cheapÂ* spin indexer I have I went to the trouble of aligning it and
milling the sides parallel to the spindle axis, I believe the Suburban
Tools indexer the cheap ones are a knock of have this as standard. I was
taught that the T slot are accurately machined and can be used for
alignment so I slot a piece of 5/8" wide cold rolled into the slot on
the BP and use that to align the indexer, quick and simple.