A good set of squares is invaluable, but don’t fall into the trap of assuming any square is accurate. There are many types of square and some are more widely useful than others. Let’s look at a few great options that deliver accuracy and relative affordability.
These engineer’s twi-squares from Faithful tools are the best I’ve found so far. They’re precision-ground and accurate to 0.016 mm on every edge. They’re well made too, though care should be taken with ant tai-square as drops and impacts can alter the position of the adjoining pieces and ruin the square’s accuracy.
The set square is highly versatile and not only makes a great centre finder, but is also great for squaring table saw mitre slots to the face of the blade.
The angle finder, known also as an angle protractor, angle rule or woodworker’s protractor is a dual-arm square that can pivot to replicate any angle. It’s great for transferring angles to a mitre saw, such as the angle of a pitched roof or a sloped box front.
The framing square or roofing square is a simple l-shaped metal plate which is great for squaring longer workpieces. They are useful in cases where the fences of thicker squares get in the way, such as cabinet face frames. They come in many sizes, a 600 mm x 400 mm being probably the most useful. A good framing square doubles up as a useful straight edge too.