Square my Square

[poolhound]

This old square belonged to my grandfather. It is ebony with a brass face and unfortunately not quite square. I could file down the blade somewhat and make it serviceable but the issue is really where the brass joins the ebony. There is a gap between them and the bass face is not straight or square.

Any ideas on how to make this workable or maybe I just use for rough "close enough" work.

[LCHIEN]

Grinding the blade down won't keep the sides parallel and may be hard to even keep the ground edge straight.

the first thing that jumps to mind is that it needs to be reset. I might consider drilling out the two diamonds to the right leaving the one on the left as a "pivot" temporarily.
Set the square so its truly square using the ability to pivot and then clamp it where its square. Drill a 1/8 or 3/16 drill and some roll pins to lock the right side - I'd carefully drill to the right of the two diamonds.

Now you've sort of got it locked with the roll pin and no play.
Now drill out the two diamond holes and use screws and nuts with clearance just to lock the ebony to the blade. Won't look as pretty as the original but it will be square.

[capncarl]

If you file the sides square you would have a mess! Are the diamonds really nuts? The other side may have the screw head concealed under similar shapes of some cover for the screw heads. I'd do a little probing before I did anything drastic. These old tools were very well built and usually had built in adjustments, you just have to know how to find them. They don't build them like this any more. I have a couple of flexible steel rulers that have been broken and repaired by splicing a simular piece onto the side and riveting it. You wouldn't know it was a repair without close inspection, and it's still very accurate.
capncarl

[wardprobst]

If the blade is not square, I would attempt to move it and reset the pins under/in the diamonds first. It doesn't take much and that's an attractive piece. You can reset them with a ball peen hammer and small punch.
DP

[JimD]

I would also try tapping it in the direction it needs to move. It probably won't move but might.

[Healey]

I have three like that, in three different sizes. The smallest is square, the other two are not. I tried forcing and tapping one of the others, but to no avail.

Were my father alive, he'd know how to fix it. (knowledge lost must be regained by trial and error) I don't think the "pins" in the diamonds are screws, I think they are draw pins. I'm going to see if they will drive out. If so, then leaving one as a pivot, it can be squared and slightly larger holes can be drilled and re-pinned.

While checking for square, I discovered that two of my modern combination squares were not square either.

[poolhound]

I found this excellent article on exactly the issue i.e. separation between the brass wear plate and the wooden stock.

https://paulsellers.com/2012/08/fixing-old-tri-squares/

He also indicates that the pins are fitted in a way that makes them not easily removable. I am going to try and remove/repair the brass plate and wood stock and see where I stand. It gives me a good reason to properly sharpen and setup my cheap bullnose plane