"John Manders" wrote in message
...
It's very easy to check a square.
Get a straight edged sheet of plywood and drw a line square to the edge.
Turn the square round and it should match the drawn line. If it doesn't,
the
square is out by 1/2 the difference between the square and the line.

John
You do not need a square to do this just cut a peice of wood and flip it
over onto itself
Same rule if the end do not line up you are out 1/2 that amount

to test a 45 degree mitre cut 4 peices the exact same length with the 45 on
each end lay them on a table
in a square if the last joint is open at all divide that distance by 8

The shortewr the sample peices are the more accurate you will be
I like peices about 6 to 8 long

Good luck,
George