Identify This Machine Part?

Miller Precision Threading Attachment for lathe

Found this in a machinists' estate. Can't figure out what it is/does?
No maker's name or model number seen.
Can anybody identify it?

Thanks

Uhhh--what part? What am I missing?

JH

That's a frangelkröckenspenner, Model 710, or possibly a tool grinder.

An early example of a manual non-turbo encabulator?

Generically, that's an dividing head (or indexer), with built-in provision for varying the worm gear ratio through a change gear set, mounted on a cross slide. The mounted-on-a-cross-slide strongly suggests it is part of some specific larger machine, and not a general accessory for a milling machine (for example).

If I had to guess what it's "off of", maybe a tool grinder of some sort? Perhaps a reamer flute grinder?

Added in edit: the currently unoccupied clamping bore is almost certainly for an overarm which would carry a bracket for either a dead center (most likely) or an indexing finger (much less likely). So this gizmo was intended for a grinding or machining operation, and not for measurement/inspection.

And a question for you, Mel in WA: Does the slide leadscrew interact with the worm wheel at all? I'm guessing not, but if it does, it would yield helical flutes in a tool-making application.

Whatever it is, I'd like to buy it. Too cool to pass up.

Mel it's a Garrett millerette indexing attachment for a lathe that has been modified and its missing the overarm and tailstock did you get the gear set that goes with it I found the gear chart in one of the tool boxes I got there Ken what its looks like http://www.lathes.co.uk/southbend9-inch/img31.gif

Thanks to everybody that helped, especially Ken who fully identified it and pointed me in the direction of the change gears which I do have.
This forum is a great resource!

It is for sale, and I have sent a PM to Ron.

Any chance this is still available? I'm looking for the same item if anyone has one. Recently acquired an incomplete Millertte attachment.

I have one with a vice that I'm looking to sell