Chisels - choosing and using

Although power saws and routers have taken a lot of the hard work out of woodwork, there's still a place for a basic set of chisels in any DIY toolbox.

Chisels concentrate hand pressure or a mallet blow into a small, sharpened area which can slice through timber with great accuracy. Even if you have to economize on other tools, buy the best set of chisels you can afford. Although they can be bought individually, a set of four (6, 12, 18, 25mm blade widths) is often the best value.

Take care, as with all sharp tools, keeping the body (particularly hands) behind the blade to avoid accidents.

Buying checklist

Check the steel blade is hardened and tempered, giving a long-lasting edge.

The handle shape and material (traditional wood or polypropylene) is a personal choice as long as the grip and size 'feels' right.
The joint between handle and blade is vital for strength. It should be either a flared section of blade or secured with a brass ferrule.
You may be able to pick up good quality second-hand chisels but don't buy if the metal is badly pitted with rust.

Storage

Store chisels safely away from other tools that may blunt the edge. Lubricate the blades with a light oil to stop rust forming.

Which type of chisel to use

Bevel edge blades have tapered sides which means the chisel can be pushed right into the corners of joints. Modern hardened steel bevel edge blades can be struck with a mallet, making them a good general purpose tool.

Firmer chisels have a rectangular profile blade which makes the blade strong enough to be used with a mallet for forming larger joints.

Mortice chisels, which are almost square shaped in profile, can be used to chop out large mortices such as door locks.

Cold chisels chop through masonry and plasters and should have a protective plastic shroud to protect your hand from stray hammer blows. You should only need a 25mm and a 100mm width for most work. Soft grip insets make the handle more comfortable.

Keep chisels sharp

Use a honing guide to set the angle for honing wood chisels and an oilstone or diamond stone to sharpen the edge. Chisels have the blades ground to an angle of around 25 degrees. Hone the very tip of the blade to about 35 degrees to provide a stronger cutting tip. If you are away from the workshop, you can re-sharpen a chisel by honing the blunt edge on fine silicon carbide paper, taped flat.

Most chisels come with a protective end cap which should be kept in place when the chisel is not being used. This will protect the blade as well as your hands.

Paring edges

Always keep both hands behind the chisel blade. Use a finger and thumb to guide the bevel for delicate work. Place your shoulder directly over the chisel when paring directly downwards, providing controlled force behind the cut.

Across-the-grain work

Make cutting across the grain easier by making a series of parallel saw cuts across the grain at 5mm intervals. Pare away the waste with as wide a chisel as possible and support the wood from underneath. Keep the chisel with the bevel face upwards so that it gives a flat level surface at the bottom of the cut. Ensure the wood does not splinter outward by working from both sides. Work towards the centre and don't try to take off more than 3-4mm at a time.

Cutting a recess

Chop around the marked edges of the recess with the chisel held vertically - bevelled edge towards the waste. Score across the grain and chop out the loosened pieces from the centre outwards.