I have a machinists 8" square and rely on it for all my tool setup.
I trust this more then the other squares I have. Got burned once
using a speed square that was off a bit (it went into the trash).
Its construction is robust and will not go out of square. Some
have suggested using a framing square but they can go out of
alignment and besides they are rather large and harder to use on a table
saw, jointer etc whereas the smaller machinists square does the job
very well. I have had mine for 10 years and use it all of the
time.

Marty

Jim In FL wrote:
I've been debating purchasing a 12" Machinist's Square. Would be awfully
nice to be able to quickly verify some of my tool setups by checking,
let's say for example, a 12" plus crosscut off my sled or sliding
miter. Or verifying, with some exactness (is that a word ?) that a
cabinet side is really square with the bottom. I'm trying to really
focus on accuracy these days in my woodworking. I'm finding that it
sure pays off in the long run over the course of a project, to spend the
extra time making sure your setups are right on, and taking the extra
time to verify at each operation.

Problem is, can I justify $60-100 for a precision square. Not a rich
man here - that's not exactly rounding error money for me.

What do you guys do ? Should I just grab my framing square and forget
spending the bucks ?

Jim In FL