Featured What do I do? Crude wooden thingy with marked measurements and bone inlay

Got this at a closing antique store for under five bucks because I just liked it. I asked the fellow what it was and he had no clue .

One end can be loosened but the screws prevent anything being slid in even as far as the beginning of the ruler. The two lines on the underside (?) Have some verdigris so I assume there were copper strips in place before.

What on earth is this? Any info much appreciated!

 

Idle guess would be woodworking tool - some kind of mortise or marking gauge, probably hand made to suit that particular user's needs.

 

That is my thinking too. And hoping I find my own use for it one day (besides display riser in a cabinet)

 

It appears the thumb screw was added sometime after the inch cuts were made. I'd measure the distance between the end of the narrow portion and the first inch marking. Is it exactly 5"?

Almost looks to me like some kind of small hand-made square. Antique Builders Square Wooden Carpenter Square - Etsy The short leg doesn't leave much room for marking though. Do the two sides separate?

 

I am not sure if my peabrain is u derstanding. But, it IS exactly 5 inches between these crude marks. I think the marks were put in with the thumbscrew in mind as the smaller increments aren't marked there at all.

I think the whole thing would come apart but I am reluctant to try as the peg opposite to the thumbscrew has pushed out a bit just feom playing with it...