Tool for squaring

[Stephen Richard]

I've published a note on a tool for squaring cartoons and panels:
http://glasstips.blogspot.com/2011/09/squaring-panels.html

[Tom]

Great tip Stephen, thanks!

[Tre V]

I made a transom last year for a friend. Thankfully I didn't assume the transom opening itself was square and level, because it wasn't. I had to adjust the glass accordingly. But, yes, Stephen Richard, this is a great method for keeping things on an even keel. Thanks for posting it.

[Rebecca]

You are right, Trev!  Don't ever assume ANYTHING is square.

Rebecca

[Scope Builder]

Here in America the tool Stephen mentions is called a "Framing Square" and is used for many framing functions from roof trusses to building stairs.  They are inexpensive and can be purchased at about any hardware store or Big Box building supply store.