Chisels

Chisels are made in a variety of patterns and sizes, but they all have one thing in common: to work effectively their cutting edges must be razor sharp. This means that less effort is required to make them cut and they are safer to use because there is less chance of them slipping. There are several styles to choose from. Tools may be sold individually or in sets of common sizes.

As much as three-quarters of the work you do with chisels will be done with tools ranging between 6 and 19 mm (¼ and ¾ in) in width. There are likely to be times when you will need wider tools — sometimes paring chisels — but these occasions will be rare. If buying chisels for the first time, obtain a good-quality set of small bevel-edge tools. These will become some of the most important hand tools in your workshop. Get the feel of using and sharpening these before investing in larger, more expensive chisels.

Chisel Choice

Sets of chisels usually contain popular blade widths  of 6, 12, 19 and 25 mm (¼, ½, ¾ and 1 in), although tools can also be bought individually. Many craftsmen rely on an assortment of small chisels less than 12 mm (½ in) wide. Unless they work regularly on large projects they will have perhaps only three other larger chisels of different widths, up to 30 mm (1 ¼ in). Choose a range of chisels that fits, and becomes an extension of,  your hands.  A handle should balance the weight of the blade — a small one for a narrow chisel and a larger one for a wider tool. Handle comfort can be as important as the hardness of the steel that forms  the cutting edge. Traditionally chisel handles are boxwood, although beech and ash are also common.Plastics such as polypropylene are popular, arguably less comfortable than hardwood, yet more durable.

The most useful chisels for workshop use are those with bevel edge. A light bevel is ground along both long edges of the chisel, making these tools ideal for cutting joints and getting into corners. Because there is less steel, however, these chisels are not as strong as other chisel patterns and should not be used for chopping mortises.

Heavier, firmer chisels are more useful for general carpentry work than for furniture-making or joinery. Their rectangular-section blades make them stronger than bevel-edged tools, although they are more limited in how they can be used. Mortise chisels have heavier blades still, designed to lever out the waste timber when chopping a joint. Available in several styles, all of them are designed to be used with a mallet. A registered-pattern mortise chisel has a steel hoop and leather washer between blade and handle to absorb shock.

Specialist Chisels

There are several less common chisels that will be useful in certain situations. The first is a matched pair of lef-t and right-handed skew-ground chisels. These are essential tools for cleaning out the corners of lapped dovetails, most commonly found on the front of drawers. You can clear those few corner fibres away with a bench knife, but a skew-ground chisel is a much more efficient tool. It is possible to grind a couple of old chisels to the required angles, instead of buying brand new tools.

Bevel-edge paring chisels are useful for fine, delicate work and should never be struck with a mallet or hammer. Their bevel-edged blades are longer than most chisels, enabling them to be used for cutting housing joints. Useful sizes are 16 mm (54 in) and 30 mm (14 in) blades. A cranked paring chisel is very useful for cleaning out the inside of an assembled carcase, its handle raised above the work when used with the blade flat on the work. Without the help of this tool, it is almost impossible to slice off neatly those tiny knobs of half-dried glue that squeeze out from a joint.

Tip :

Long adges of new chisels can be sharp, cutting into your fingers when used for paring. Run at fine sharpening stone along the edges to soften them.

Japanese Chisels

Unlike a European chisel, the blade of a Japanese chisel is laminated. A thin layer of hard steel (the cutting edge) is laminated to a heavier layer of softer steel. If used properly, Japanese chisels retain their edges several times longer than European equivalents. They are honed in the same way as Western tools, though usually with just one bevel, rather than two.

Larger Japanese chisels benefit from the oriental practice of hollow grinding. This enables the user to get the back of the chisel perfectly flat and mirror polished. As the hollow is gradually revealed along the edge through repeated honing, a special hammer is used to restore the cutting edge. Most Japanese chisels have a steel hoop on the handle, so they can be struck with a small metal hammer. Handles are usually made from polished oak and beautifully finished. Although there are benefits to be gained from buying Japanese chisels in larger sizes, many craftsmen prefer European chisels in the smaller, more delicate sizes. European chisels are lighter, easier and quicker to sharpen than Japanese versions.

How To Use Chisels

When using a chisel, the sharpness of the edge is paramount. Never let the edge become blunt — as soon as you feel the need to exert undue pressure when paring, it is time to hone the edge. When a chisel is in constant use, it is not unusual to need to hone an edge once every half hour or so. Always keep both hands behind the cutting edge. Never be tempted to hold a work piece in one hand while chiselling with the other. Instead, always grip timber in the vice or to the bench top using a cramp.

Paring To Gauge Lines

When paring back to a gauge line, always pare away a shaving that is not too thick. This is because a chisel blade is in fact only a sharpened steel wedge. If the shaving you are attempting to remove is too thick, instead of allowing the chisel to pare at right angles to the surface it will drive the tool back, possibly inside the gauged line.

As you approach the gauge line, pare three-quarters of the way down the end grain. Then turn the timber over and pare down from the other side. In this way you will approach the gauge lines with the end grain becoming flatter at right angles to the face side. When you come to the final shaving, click the chisel into the gauge line (you should feel the sharp edge of the blade engage with the line) and make the final cut three-quarters of the depth. Turn the piece over and complete the cut to give you an exact 90-degree surface to the face side.

How To Pare Horizontally

Cramp the work piece vertically in the vice for horizontal paring, about 152-203 mm (6-8 in) above the bench top. At this height it is possible for the timber not to vibrate too much and yet enable you to get into the correct stance.

1.Stand with legs apart and your chest and shoulders at right angles to the face of the timber. The line from the chisel blade through your wrist to your elbow should be straight, and almost parallel to the bench top: you may need to spread your feet further apart. In this stance, power is given to the cut by tucking your elbow tight into your chest. Lean on your knees and upper body instead of applying power with the arm and shoulder.

2. Greater control and flexibility can be provided by using a paring chisel. The length of the tool enables you to exert much finer control over the cuts.

How To Pare Vertically

Hold the chisel close to your body with elbows tucked in, so you can exert the power from your upper body rather than hands and forearms. Rest your forearm on the timber and grip the chisel with an upward pressure. Use your other hand to hold the chisel handle and exert downward pressure. This way, you hold the tool in tension, giving greater power and control. You can drive the blade through end grain and yet control the cut, preventing the chisel from skating away from you and digging into the bench. It is a good idea to use a cutting board to protect the bench top just in case.

1. With a narrow chisel of about 6 mm (¼ in) it is possible to pare relatively soft timber (such as mahogany or walnut) the full width of the blade. With a wider blade it is difficult to retain control of the tool, so start with a narrow chisel first.

2 Work up to using the widest chisel available, as its width will give you greater accuracy and flatness.

Word Discription :

Honing After grinding, edge tools are honed (sharpened) on an abrasive stone to produce a cutting edge.

Paring Removing a thin shaving from timber with a sharp chisel, either from the surface or from end grain.

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