What Is Chisel?
Chisel, a cutting tool with a sharpened edge at the end of a metal blade, is used often by driving with a mallet or hammer in dressing, shaping, or working a solid material such as wood, stone, or metal.
A chisel is a tool with a characteristically shaped cutting edge (such that wood chisels have lent part of their name to a particular grind) of the blade on its end, for carving or cutting a hard material such as wood, stone, or metal by hand, struck with a mallet, or mechanical power. The handle and blade of some types of chisels are made of metal or of wood with a sharp edge in it.
Chiseling use involves forcing the blade into some material to cut it. The driving force may be applied by pushing by hand, or by using a mallet or hammer. In industrial use, a hydraulic ram or falling weight (‘trip hammer’) may be used to drive a chisel into the material.
A gouge (one type of chisel) serves to carve small pieces from the material, particularly in woodworking, woodturning, and sculpture. Gouges most frequently produce concave surfaces. A gouge typically has a ‘U’-shaped cross-section.
Chisel comes from the Old French cisel, modern ciseau, Late Latin cisellum, a cutting tool, from caedere, to cut. Flint ancestors of the present-day chisel existed as far back as 8000 BC. The Egyptians used copper and later bronze chisels to work both wood and soft stone. Chisels today are made of steel, in various sizes and degrees of hardness, depending on use.
Chisels are common in the archeological record. Chisel-cut materials have also been found.
How to Use a Chisel?
It is important to choose the type of chisel best suited to the work that you will be carrying out. Additional factors such as the chisel size and blade shape should also be taken into consideration.
Work should begin with a general inspection of the chisel to ensure that it is in the best possible condition. A square can be used to check the flatness of the blade. It may be necessary to sharpen the chisel to ensure that it is well protected throughout the process.
Once the tool itself is in order, a ruler and carpenter’s square can be used to measure the area of the surface and depth to be removed during the chiseling process. You should then proceed to clamp the wood, ensuring that it will remain fully stable when being chiseled.
To make a small indentation when working with wood, the chisel should be positioned at a 90-degree angle. A wooden mallet can then be used to strike the chisel and carve out the desired amount of wood. The chisel should be held with the beveled edge closest to the wood.
Next, proceed to run the chisel following the wood grain. The scored area should be chipped away until the wood inside the outline has been extracted to the required level. Care should be taken to strike away from the body and only extract a small amount of wood with each strike.
Paring chisels are well suited to woodworking tasks requiring a high level of intricacy and precision. The paring process involves the gradual smoothing and removal of surface layers. Once the wood has been firmly secured on the workbench or vice, one hand should be kept on the chisel’s blade with the other on the handle. It is common to use your non-dominant hand to secure and guide the chisel.
The bottom of the chisel should be kept in contact with the wood throughout this process. The cuts should be repeated at a gradual rate until the desired amount of wood has been extracted.
Masonry chisels can be used for scoring, trimming, or shaping materials such as brick and stone. It is important to select a masonry chisel of an appropriate shape and width for the particular task at hand. Before beginning work, it is recommended to mark the material to be chiseled with pencil or paver’s chalk. Scoring marks can then be inserted along this line in preparation for chiseling.
The masonry chisel should be set at a perpendicular level of 90 degrees for precise entry into the brick or stone. The mallet can then firmly strike in the center of the scoreline, repeating the process until there is an even break.
Regardless of the particular type of chisel in question, it is recommended to keep a honing stone to hand, so the chisel can be sharpened as and when required. Additionally, the bevel can be sharpened and refined with the use of a grinder. Once this has been completed, it is possible to proceed to hone and polish the chisel blade.
How to Use a Wood Chisel?
A sharp wood chisel can cut mortises, shave rough surfaces, chop out corners and scrape off glue. We’ll demonstrate these techniques and show you how to sharpen your chisel. The wood chisel is an indispensable member of your toolset. We’ll show you how to get the most out of it.
Technique 1: Mortise cuts
Face the bevel down. Push or tap the back of the chisel to remove thin slices. Control the depth by raising and lowering the handle.
Start recesses or mortises by outlining the area with a sharp utility knife or by making a series of shallow chisel cuts perpendicular to the surface. Skip this step and you risk chopping wood outside the mortise. Then remove thin slices by tapping the chisel with a hammer, bevel side down, to carve out the wood inside the perimeter.
Chiseling with the grain can sometimes have disastrous results. If the grain runs deeper into the wood, it’ll direct the chisel too deep. Stop and chisel from the opposite direction if you feel this happening.
Technique 2: Paring cut
Pare thin slices of wood to flatten the bottom of an open recess. Keep the back of the chisel flat on the wood. For easier slicing, pivot the chisel as you cut to move the blade in an arc.
If the recess is open on one side, like a hinge mortise, flatten the bottom by paring off thin slices with the back, unbeveled side of the chisel held flat to the wood.
In general, when you’re shaving into a piece of wood, face the bevel down. When you’re flattening a cut and have access from the side, face the bevel up and hold the back of the chisel tight to the surface.
Technique 3: Chopping cut
Chop out large Amounts of wood by slicing off small amounts with each cut. Strike the chisel with a hammer and chop down about 1/2 in. Then chisel from the end to remove the piece before continuing. Your chisel must be sharp for this cut.
Caution: Wear safety glasses.
Set the chisel alongside one cut edge and strike it sharply with a hammer to remove wood from notches. This isn’t fine work; the cut will be hidden by another board.
Technique 4: Chop and pare
Cut a groove, or dado, by first sawing along both edges to the desired depth. Then break out the wood in the middle with your chisel. Space the chisel cuts about 1/2 in. apart.
Chisel out dadoes and other more precise joints a little at a time with a series of shallow cuts rather than driving the chisel too deep. Use a hammer or mallet for rough work or press with the heel of your hand for lighter cutting chores or finer cuts.
Technique 5: Scraping
Scrape glue joints or other imperfections from wood projects by holding the blade at a right angle to the wood with the back of the chisel facing you. To remove thin shavings, support the blade with your fingers and press down while you draw the chisel toward you.
Scraping requires a perfectly flat, sharp edge. The chisel tip should scrape cleanly without leaving scratch marks in the wood.
Types of Chisels
1. Woodworking chisels
Woodworking chisels range from small hand tools for tiny details, to large chisels used to remove big sections of wood, in ‘roughing out’ the shape of a pattern or design. Typically, in woodcarving, one starts with a larger tool and gradually progresses to smaller tools to finish the detail.
One of the largest types of chisels is the slick, used in timber frame construction and wooden shipbuilding. There are many types of woodworking chisels used for specific purposes, such as:
- Firmer chisel has a blade with a thick rectangular cross section, making them stronger for use on tougher and heavier work.
- Bevel edge chisel can get into acute angles with its beveled edges.
- Mortise chisel thick, rigid blade with straight cutting edge and deep, slightly tapered sides to make mortises and similar joints. Common types are registered and sash mortice chisels.
- Paring chisel has a long blade ideal for cleaning grooves and accessing tight spaces.
- Skew chisel has a 60-degree cutting angle and is used for trimming and finishing across the grain.
- Dovetail chisel made specifically for cutting dovetail joints. The difference being the thickness of the body of the chisel, as well as the angle of the edges, permitting easier access to the joint.
- Butt chisel short chisel with beveled sides and straight edge for creating joints.
- Carving chisels used for intricate designs and sculpting; cutting edges are many; such as gouge, skew, parting, straight, paring, and V-groove.
- Corner chisel resembles a punch and has an L-shaped cutting edge. Cleans out square holes, mortises and corners with 90-degree angles.
- Flooring chisel cuts and lifts flooring materials for removal and repair; ideal for tongue-and-groove flooring.
- Framing chisel usually used with mallet; similar to a butt chisel, except it has a longer, slightly flexible blade.
- Slick a very large chisel driven by manual pressure, never struck.
- Drawer lock chisel an all-metal chisel with 2 angled blades used for tight spaces, like cutting out the space for fitting a desk drawer lock.
2. Metalworking chisels
A chisel set is for metalworking projects. Cold chisels can carefully scrape excess material from soft metal pieces. The flathead can cut through metal sheets or shave notches through the surface with its resilient steel construction. When punching holes in aluminum, try using a chiseling tool that narrows to a precise point and strike the device with a hammer to puncture metal.
Chisels used in metalwork can be divided into two main categories: hot chisels and cold chisels.
2.1 Hot chisel
A hot chisel is used to cut metal that has been heated in a forge to soften the metal. One type of hot chisel is the hot cut hardy, which is used in an anvil hardy hole with the cutting edge facing up. The hot workpiece to be cut is placed over the chisel and struck with a hammer.
The hammer drives the workpiece into the chisel, which allows it to be snapped off with a pair of tongs. This tool is also often used in combination with a “top fuller” type of hot cut when the piece being cut is particularly large
2.2 Cold Chisels
Cold chisels are used to cut heavy metal that cannot be cut with a saw or shears, usually because space is limited. They are also used for any number of repair jobs, such as cutting off rivet heads or slicing through rusted nuts and bolts, and other heavy work.
Before machine tools became available, cold chisels were more widely used in general engineering. Metal components were often made as close to the final size as possible by casting so that most of the work in shaping the metal was done by the furnace.
Cold chisels were then used to cut away material from the areas of the casting that needed to be brought to an exact size. These areas were then finished by filing and scraping.
To make a cold chisel heat the end of the bar of tool steel until it is bright red and hammer to the desired shape. You will need to reheat the bar several times as it cools quite quickly when you hammer it. If you don’t have a blacksmith’s anvil you can use the face of a large sled hammer instead (if the face is not too scarred).
Clamp the sledgehammer in a large vice to keep it steady. Don’t strike to face of the sled hammer with your forging hammer or you may knock off chips of hardened steel which can damage your eyes.
Once the end of the bar has been hammered to the right shape you can grind the cutting edge as shown in the diagram. Harden the bar and then temper it to make the edge tough so that it does not crack. Different materials will require slightly different edge grinding and tempering.
3. Stone Chisels
With so many types of stones for sharpening, it can be difficult to determine what the best stone is for your woodworking needs. Fortunately, the variety of stone materials will allow you to select a material that will meet your needs and stay within your budget.
The three main types of bench stones are oil stones, Waterstones, and diamond stones. Since every woodworker’s needs and preferences are different, understanding the advantages of each stone will allow you to be a more informed purchaser of sharpening stones.
Oilstones are traditional stones that have been popular for years. Today they are available in man-made and natural stones. The man-made stones are made of either silicon carbide or aluminum oxide abrasives. These are generally available in coarse, medium, and fine grades.
The natural stones are made of novaculite and are available in grades such as Soft Arkansas, Hard Arkansas, and Hard Translucent Arkansas; the harder the grade, the finer the grit of the stone. Natural stones are generally finer grits than man-made stones so it is common to have both man-made and natural oilstones in your sharpening kit.
Waterstones has become very popular among woodworkers because they cut faster than oilstones. Like the oilstones, Waterstones is available in both a man-made and a natural variety. However, in the western world, man-made stones are significantly more popular.
Most Waterstones are made of aluminum oxide abrasive. While this is the same type of abrasive material as used in some oilstones, the stones are quite different. First, unlike oilstones, Waterstones use water to remove the swarf.
Using water makes it easier to clean up and more convenient to use. Secondly, Waterstones cut faster than comparable oil stones because the binding material that holds the stone together is softer. The softness of the stone allows the stone to cut faster because sharp new material is constantly being uncovered. However, the softness is also the biggest disadvantage of the Waterstone because it must be flattened regularly.
3.3. Diamond Stones
Many woodworkers are catching on to the advantages of diamond stones for some good reasons. Unlike oil and water stones, diamond stones are all man-made. These industrial diamonds are applied to a metal backing to create an abrasive surface.
The diamond stone can be extremely versatile. It can be used to sharpen any woodworking tool. It can even sharpen carbide-tipped router bits that both oil and water stones can’t touch.
Diamond stones do not wear unevenly because the diamond surface is so hard. Because of this diamond stones can be used to flatten oil and water stones.
4. Masonry Chisels
Masonry chisels are typically heavy, with a relatively dull head that wedges and breaks, rather than cuts. Often used as a demolition tool, they may be mounted on a hammer drill, jackhammer, or hammered manually, usually with a heavy hammer of three pounds or more. These chisels normally have an SDS, SDS-MAX, or 1-1/8″ Hex connection.
Some masonry chisels are designed for cutting soft stone, while others will stand up to harder use.
Like brick chisels, masonry chisels are generally used only to score the stone; as with glass cutting, the task involves scoring first, then breaking along the scoreline. Gentle taps on the chisel create the scoreline, allowing the stone to be snapped off when the line has been completed.
Floor chisels are another variety of chisels that can be used to scrape floors, clear off blobs of concrete, and do other rough chisel work.
Types of masonry chisels include the following:
- Moil (point) chisels
- Flat chisels
- Asphalt cutters
- Carbide bushing tools
- Clay spade
- Flexible chisels
A plugging chisel has a tapered edge for cleaning out hardened mortar. The chisel is held with one hand and struck with a hammer. The direction of the taper in the blade determines if the chisel cuts deep or runs shallow along the joint.
What is Gouge Chisel?
A modern gouge is similar to a chisel except its blade edge is not flat, but instead is curved or angled in cross-section. The modern version is generally hafted inline, the blade and handle typically having the same long axis.
If the bevel of the blade is on the outer surface of the curve the gouge is called an ‘out-cannel’ gouge, otherwise, it is known as an ‘in cannel’ gouge. Gouges with angled rather than curved blades are often called ‘V-gouges’ or ‘vee-parting tools’.
The blade geometry is defined by a semi-standardized numbering system that varies by manufacturer and country of origin. For each gouge, a “sweep number” is specified that expresses the part of a circle defined by the curve of the blade.
The sweep number usually ranges from #1, or flat, up to #9, a semi-circle, with additional specialized gouges at higher numbers, such as the U-shaped #11, and a v-tool or parting tool, which may be an even higher number such as #41.
In addition to sweep, gouges are also specified by the distance from one edge of the blade to the other (this corresponds to the chord of the circle section defined by the edge of the blade). Putting these pieces together, two numbers are used to specify the shape of the cutting edge of a gouge, such as a ‘#7-20mm’. Some manufacturers provide charts with the sweeps of their blades shown graphically.
In addition to varying blade sweeps, bevels, and widths, blade variations include:
- ‘Crank-neck’ gouges, in which the blade is offset from the handle by a small distance, to allow working flat to a surface
- ‘Spoon-bent’ gouges, in which the blade is curved along its length, to allow working in a hollow not otherwise accessible with a straight bladed gouge
- ‘Fishtail’ gouges, in which the blade is very narrow for most of its length and then broadens out near the working edge, to allow working in tight spaces.
All of these specialized gouges allow a craftsperson to cut into areas that may not be possible with a regular, straight-bladed gouge.
The cutting shape of a gouge may also be held in an adze, roughly as the shape of a modern-day mattock.
Gouges are used in woodworking and arts. For example, a violin luthier uses gouges to carve the violin, a cabinetmaker may use it for running flutes or paring curves, or an artist may produce a piece of art by cutting some bits out of a sheet of linoleum.