There are a number of tools available to accurately mark guidelines for cutting etc. These are called squares, bevels and gauges.
Squares
A square is used to mark guidelines when a right angle is required. The three main types of square are the carpenter’s square, the framing square and the combination square.
Carpenter’s square
DIY enthusiasts will generally use a carpenter’s square, which is also known as a try square. It is made up of a wooden handle known as a stock and a rectangular metal blade. The blade extends from the stock at a rigid right angle, so that when the stock is positioned firmly against the edge of a timber plank, the blade will form a right angle across its width. Simply draw along the edge of the blade with a pencil to mark the guideline.
Framing square
DIY enthusiasts will generally use a carpenter’s square, which is also known as a try square. It is made up of a wooden handle known as a stock and a rectangular metal blade. The blade extends from the stock at a rigid right angle, so that when the stock is positioned firmly against the edge of a timber plank, the blade will form a right angle across its width. Simply draw along the edge of the blade with a pencil to mark the guideline.
Combination square
This versatile variation of the square can fulfil several functions. Its rigid rectangular blade takes the form of a 300mm (12in) steel rule that fits into a metal stock, which has an angled face that allows 45° guidelines to be marked as well as right angles. Some combination squares will also have a spirit level incorporated into the stock.
Try square
A woodworking tool used for making accurate marks when timber has to be cut square and for checking that planed timber is square. The metal blade is fitted at right angles to the stock forming an L-shape. They vary in size with the largest having a blade 300mm long.
Adjustable bevel (sliding bevel)
This tool can be set at any angle. A wing nut on the stock can be loosened, allowing the stock to slide along the blade and positioned at the required angle. Simply set the blade to the correct angle and tighten the wing nut.
Carpenter’s pencil
When marking guidelines on smooth surfaces an ordinary pencil will be sufficient. But if you need to mark guidelines on rough wooden surfaces a carpenter’s pencil will be much more effective because the lead is wider and flatter.
Gauges
A gauge is a simple but effective carpenter’s tool for accurately scoring guidelines on timber.
Marking gauge
A marking gauge consists of two main parts: the stock and the stem. The stem is inserted through a hole in the stock just slightly larger than itself. This allows the stock to move up and down the stem. A retaining nut on the side of the stock is tightened to fix the stock firmly in position. A marking pin is positioned towards the top of the stem.
The distance between the marking pin and the top face of the stock will be the measurement scored into the timber. Set the gauge at the required measurement, tightening the retaining nut to hold the stock firmly in position. With the top face of the stock pressed against the edge of the timber and the marking pin against the surface of the timber, draw the gauge along the whole length of the timber. The marking pin will leave a scored guideline on the timber parallel to its edge.
Mortise gauge
A mortise gauge is similar in design to the marking gauge but with two marking pins allowing it to score two parallel lines in a piece of timber. This type of gauge can be used to mark out the position of a mortise lock on a door edge. One marking pin is in a fixed position towards the end of the stem, while the second marking pin is adjustable and is moved by turning a wheel, which is sometimes positioned on the base of the stem. The mortise gauge is used in exactly the same way as the mortise gauge but it will score two parallel lines on the timber.