Looks like part of a combination square

[skipskip]

But it's a design I haven't seen before.

no name that I find , yet

any ideas?

oct326 by Skip Albright, on Flickr

oct327 by Skip Albright, on Flickr

[Yadda]

Per Google image search

This is a vintage Chaplin's Patent Standard Tool Co. center square, an antique measuring and marking tool used in woodworking and metalworking.
This specific item appears to be the main body of the tool, known as the head or base, which is made of cast iron.
It is designed to attach to a steel rule (which is missing in this image) to accurately find the center of round stock or mark 90-degree angles.
These tools were produced in the late 19th century, with patents dating to the 1880s.
The base shown is likely a 6-inch size, a less common variant among the original offerings of 4, 5, and 6-inch bases.

[skipskip]

Thank you

[Bill Houghton]

And utterly useless, and I'll dispose of it for you so it doesn't clutter up the shop, just let me know and I'll send you my address 

Neat find.

[Yadda]

And utterly useless, and I'll dispose of it for you so it doesn't clutter up the shop, just let me know and I'll send you my address 

Neat find.

+1

[skipskip]

Came in a heap of stuff, now I need to find the straight edge that goes with it