2.5 inch wide 4"x6" angle iron. Half inch thick!
6 Welding squares for less than $20. I had this heavy piece of angle left over from a project kicking around for a couple years. My local metal supplier sells me steel by the pound and this piece would have been under $20. I have been wanting more squares and they have been too expensive for the little I would use them.
This angle was very close to true 90 with only a little sanding and grinding to bring it into spec. You will see I made 2 of these a little narrower for smaller jobs and I cut the inside rounded corner out to make it true inside as well.

A few tools used in this project I will link below. I want to shout out to Olson saw blades. I bought this king bandsaw over 6 years ago and I broke the 2 blades that came with it new in the first week. After a bunch of research and reading a lot of reviews I bought 3x 64.5" @14 TPI BiMetal blades and only put the 3rd blade on during this job. 3 years for 3 blades!

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Olson saw blade https://amzn.to/3pJSLPI

Silver Streak welders pencil. https://amzn.to/3zeXiwO

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