Squarness Comparator

[rossbotics]

Hi Doug,

I have two questions. Assume that I have your device and a surface plate but don't have a precision cylinder square or other high accuracy orthogonal reference.

1. Is it possible to test the squareness of an ordinary machinist's square - the L-shaped style? In particular, is the outer edge of the square's blade perpendicular to the surface plate when the square's body (the chunky part of the square) is placed on the plate?

2. Is it possible to test the squareness of the inner edge of the blade to the inner edge of the square's body ?

I have my own ideas about how to do these tasks but I want to hear how an expert would do it before prejudicing the discussion. If either of these is doable, could you describe how you would do it, please?

Hi Marv
with this tool I call a squareness comparator you could only check one side of the machinist square, and that would be the side where the body of the square is pointing away from you, but then you have to check the other side as a reference to the adjacent side, this is where the cylinder square comes into play, there is another way to check your square but not with the squareness comparator, instead of me explaining to you how to do this I attached a video of how to do this operation, this is how we use to it.
Thanks for asking
Doug