Two items that fall in the "what is it" category

[JustKeepDigging]

Two items that fall in the "what is it" category

I have no idea what these two things are, found them earlier today. The bolt thing is marked "general hdwe mfg co N.Y.C. The other thing kinda looks like a key?

 

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[50bmg]

first 2 pics are clamps for a framing square for doing layouts of stairs and rafters

https://www.homedepot.com/p/Empire-3-4-in-Brass-Stair-Gauges-2-Pack-105/100162901

 

[50bmg]

third pic looks to be part of a baseplate for a saw
that v notch would be where you would follow your cut line

 

[JustKeepDigging]

Thank you guys, nailed it.