SQUARES & T-BEVELS

Squares are used to make sure things are at a right angle to one
another. In a woodshop, these things might be the edge of a board, the shoulder of a tenon, the fence on a jointer and so on. However, square is an abstract term.
Looked at closely enough, nothing is truly square; some things just approach the
idea of being square than others. There are three types of square generally used in
woodworking.

framing SQUARE

these are made for house building. They have
two large blades that form a right angle. One blade is 2in wide by 24in long; the other is 1 ½ in by 18in long. Framing squares are not expected to be precise as try squares or engineer’s squares.

TRY SQUARE

are the most commonly used squares among furniture makers. They have blades of brass or steel (generally from 6in to 12in long) set in a thicker wood or metal stock. If the stock is wood, it should be faced with metal to ensure long-term accuracy. The reliability of try
squares can vary sharply, even among those made by the same manufacturer.

engineer square

these are similar in design to the try squares,
but made entirely of steel. Blades lengths start at approximately 2 in. these squares are more reliable than try squares, probably because engineers are a more demanding bunch than woodworkers. Engineer’s squares can
be used interchangeably with try squares in a woodshop.

t-bevel

A sliding T bevel, also known as a bevel gauge or false square[1] is an adjustable gauge for setting and transferring angles. The handle is usually made of wood or plastic and is connected to a metal blade with a thumbscrew or wing nut. The blade pivots and can be locked at any angle by loosening or tightening the thumbscrew.

In use

The bevel can be used to duplicate an existing angle, or set to a desired angle by using it with any number of other measuring tools (such as a protractor, or framing square).[2]