Chisels Buying Guide...
It is hard to believe that the chisel, as we recognise it today, has been used since the times of the ancient Egyptians. Available in many different profiles and forms, chisels are still the best way of accurately and efficiently cutting and shaping wood and are often seen as the most important tool in the workshop. Every woodworker should own a set of good quality chisels. A sharp chisel that feels comfortable and well balanced in the hand is a joy to use and can improve the quality of the resultant work dramatically.
Anatomy of a Chisel
Primarily consisting of a blade and a handle, understanding how a chisel is constructed allows it to be used more efficiently.
The blade, which is usually forged from a single piece of steel, features the cutting bevel at one end and either a tang or a socket at the other.
The angle of the cutting bevel is an important consideration when selecting a chisel as this gives an indication for what the chisel is designed for. Shallow angles, around 20-25 degrees are ideal for paring, 25-30 degrees gives a good general purpose cutting edge and above 30 degrees allows for heavier cuts to be made.
The micro bevel is a secondary bevel that is often honed on to the cutting bevel by the user. Normally 1-2 degrees steeper than the angle of the main cutting bevel, the micro bevel edge is all that requires honing when the chisel dulls. Some chisels feature bevelled sides giving extra clearance to the edge allowing it to cut right in to a corner.
The shoulder of the blade is at the end of the main cutting blade and is where the blade begins to taper towards its narrowest point, the neck. From here the neck increases in width to create the bolster.
The bolster is important as it forms the blade's main point of contact with the handle. A bolster that fits correctly against the handle with no gaps and has full contact with the handle offers a better transference of energy from the handle to the cutting edge. Not normally seen, the tang is an integral part of the main blade and forms a solid anchor in the tool handle.
The handle is most often made from either hardwood or a split proof synthetic material and is usually contoured to give the most appropriate grip for the function of the chisel. A ferrule, situated above the blade bolster at the bottom of the handle, gives support to both the handle and the tang, preventing the handle from splitting. Depending on the type of chisel, some handles may feature reinforcing hoops around the top to prevent the handle from spreading when repeatedly hit with a mallet. ©
Types of Chisels
Bevel Edge Chisels
With a cutting angle of between 25 and 30 degrees, bevel edge chisels are widely recognised as the workhorse of the workshop. Extremely versatile in their use, bevel edge chisels are used for making paring cuts where thin, fine shavings are taken as well as smaller, lighter duty morticing and stock removal tasks, and are a good starting point for any chisel collection. Bevel edge chisels are characterised by the side bevels on their blades that allows the chisel to access tight corners and areas not easily accessed by other styles of chisel. As a general rule, those bevel edge chisels that feature a reinforcing hoop or cap at the top of the handle are designed to be struck with a mallet. ©View our Range of Bevel Edge Chisels
Skew chisels are simply bevel edge chisels with the cutting edge angled to present a prominent point at either the left hand side or right hand side depending on the skew. The skew itself is normally set at an angle of between 45 and 70 degrees and the sharp point is perfect to clean out sharp corners such as those on dovetail pins. The skewed blade can also be used like a hand plane and gives a far superior finish when used for paring and finishing cuts on end grain compared to a straight edged chisel. Skew chisels are sold in pairs with one left hand skew and one right hand skew. ©View our Range of Skew Chisels
Much shorter in length than standard bevel edge chisels, butt chisels are used when accuracy of cut is important. The butt chisel features the same cutting bevel angle of 25 to 30 degrees as its larger counterpart but the shorter blade is easier to control and much less likely to wander from its mark when struck or pushed. Ideal for taking fine finishing cuts as well as for working shallower mortices such as hinge mortices, butt chisels feature handles proportionate in size to their bodies making them easy to hold in the palm of the hand. ©View our Range of Butt Chisels
Firmer gouges are specifically used for cutting flutes and curved profiles in wood. The U shaped blade features a straight grind to the cutting bevel leaving the corners of the cutting edge intact. These gouges are designed to be struck with a mallet to assist cutting and feature reinforcing hoops at the tops of the handles to support the handles. ©View our Range of Firmer Gouges
With a cutting bevel angle of 30 degrees and over, the mortice chisel is built for heavy work. As the name suggests, the mortice chisel is primarily used for cutting mortices. Different in design to any of the other chisels, the mortice chisel has a thick, narrow blade which gives the chisel the strength needed to cut and lever the excess wood from a deep mortice. The sides of the chisel taper slightly to prevent the chisel from getting stuck in the wood. Mortice chisels are designed to be struck with a mallet and feature hoop reinforced or steel capped handles. ©View our Range of Mortice Chisels
Timber Frame Slicks
Specifically designed for cutting long sweeping channels and cleaning out large mortices, the timber frame slick features a thin, bevel edge blade. Characteristic to the slick is its over long handle allowing the user to cut under their own force without the need for a hammer or mallet. Used for finishing cuts, the timber frame slick is not designed to be used with a hammer. ©View our Range of Timber Frame Slicks
Timber Frame Chisels and Gouges
Designed for the heavy duty cutting that timber frame and log construction requires, timber frame chisels and gouges feature thick blades and curved, rather than flat, cutting bevels. The curve of the bevel makes it easier to cut deep mortices and prevents the chisel from getting stuck in the wood. These chisels are supposed to be struck with a hammer or mallet to facilitate the cut and are supplied with handles that feature steel end caps or reinforcing hoops. ©View our Range of Timber Frame Chisels and Gouges
Traditional Japanese chisels or Nomi, feature bi-metallic blades. This is usually an extremely hard tool steel with a softer iron or steel forge welded over the top. The harder a steel is, the sharper an edge it is able to take but unfortunately, the harder the steel, the more brittle it becomes. For single metal blades there is a maximum hardness that can be reached before a blade becomes too brittle to be used practically. With the Japanese bi-metal blades, the softer top layer acts like a shock absorber to the harder metal cutting layer ensuring that the hammer blows that would damage or crack a single metal blade of the same hardness has little effect on the Japanese blade. The short blades of the Japanese chisels increase in taper from the heel of the cutting bevel and this shape allows them to cut recesses much deeper than the chisel's blade length. To reduce the contact area and, therefore, friction between the wood and the chisel, the back is hollow ground which prevents the tool from becoming stuck. Mounted on proportionately sized hardwood handles, these chisels are designed to be struck with a metal hammer and feature thick steel reinforcing hoops at the tops of the handles. ©View our Range of Japanese Chisels
Features to Consider When Buying a Chisel
1. Handle - Wood or Plastic?
It is worthwhile taking some time to consider what type of handles you would like your chisels to have. Both wood and plastic have their advantages and their disadvantages. Wooden handles are aesthetically more pleasing than their plastic counterparts and can offer greater comfort when used for prolonged periods of time. Plastic handles are often marketed as split proof and are ideal for very heavy duty work. If you opt for wooden handles, always choose handles that are made from slow growing, straight-grained hardwoods such as ash, hornbeam, oak and beech. The straight grain gives the handle strength and is less likely to fail due to a hidden imperfection in the wood. ©
2. Bolsters and Ferrules
Bolsters and ferrules are important features on a chisel. Both designed to give support, you should look for chisels that have bolsters that are approximately the same diameter as the bottom of the handle. This ensures that, with use, the blade tang cannot be driven further in to the handle causing it to split. Ferrules around the bottom of the handles give extra support to the handles and blade during levering functions and again prevent the handle from splitting. ©
3. Blade - What Type of Steel?
In recent years, more and more tool steel alloys have been developed specifically for edge tools and distinguishing between then is often difficult. Many chisels are now made from high speed steel (HSS) and alloys of chrome vanadium. These are much harder than very popular high carbon steel and are less susceptible to the problems associated to this metal such as losing temper and become brittle if the blade gets too hot during sharpening. Chrome vanadium alloy steel is less prone to metal fatigue than other steels making it the ideal steel for those chisels which are designed to be struck by a mallet. ©
4. Steel Hardness - Rockwell Testing
The hardness of the steel is shown using the results of the Rockwell test for that particular chisel. Normally show as a range such as Rc 60-61, the R signifies Rockwell, the c indicates which test has been used - it is always c for tool steels and the numbers indicate the hardness of the steel. The higher the number, the harder the steel. Harder steels take longer to sharpen and hone than softer steels but the pay off with this is that a harder steel will retain a sharper edge for much longer. ©
5. Hardened and Tempered Blades
Look for chisels that have been hardened and tempered along the entire length of the blade. Over the cycle of using and sharpening, the blade will get shorter as metal is removed at each sharpening. A blade that is hardened along its full length will take as keen an edge when the blade is 5cm long as it did when it was 25cm long. Cheaper chisels have only the first 3 or 4cms hardened giving the chisel a very short lifespan. ©
Tips From the Experts
1. When marking out use a marking knife rather than a pencil. A thin score line is more accurate than a broad pencil mark and it also gives a starting channel to place the chisel edge in to. ©
2. Always strike or force the chisel in line with the cut. This makes cutting more accurate and more efficient than when the force or strike is slightly off axis.. ©
3. Rounding off the heel of the cutting bevel will help to prevent the chisel from getting stuck when cutting deep in to the wood. ©
4. Keep the cutting edge sharp. When the performance of the chisel starts to drop even slightly, it is time to sharpen it. You are more likely to injure yourself using a blunt chisel. ©
5. When working with chisels that are designed to be struck, a wooden mallet rather than a metal hammer is preferable as it is much less likely to damage that chisel handle. ©
MHG make all of their edge tools in Germany from the finest quality materials. Their chisel blades are made from German chrome vanadium steel, a hard metal which is particularly resistant to metal fatigue. Each blade is hardened and tempered along its entire length giving the maximum possible working life to the tool. Available with hardwood and split proof handles, MHG chisels are built for hard work but offer the finesse required for fine cabinet work.View our Range of MHG Chisels
Not a brand usually associated with carpentry chisels, Pfeil of Switzerland have made their name for producing the world's finest carving tools. With over 100 years of knowledge and experience. Pfeil understand what is required to make the ultimate edge cutting tools. Using chrome vanadium alloy steel, their chisels are highly resistant to metal fatigue and are fully hardened to give a long working life to each chisel. These tools are produced for the master craftsman.View our Range of Pfeil Chisels
Sharpening & Maintenance
Chisels can be sharpened manually on sharpening stones or mechanically using grinding machines. ©
With any new chisel, it is essential to flatten and polish the back of the blade. The cutting edge of the chisel is formed where the cutting bevel and the back of the chisel converge. ©
When sharpening, it is important to maintain the angle of the bevel. A good honing guide is a worthwhile investment if you are choosing to sharpen your chisels using bench stones. ©
If you are sharpening using different grades of stones, begin with the coarsest grit and work up to the finest grit. To prevent contamination of the stones by other grits which can damage the blade, clean the blade thoroughly before using the next grade of stone. ©
Once the back of the chisel is polished, use only the final polishing grit to remove the burr from the back of the blade. ©
For faster sharpening, hone a micro bevel on the edge of the chisel. This only needs to be 1 or 2 degrees steeper than the cutting bevel angle but the micro bevel will replace the cutting bevel as the cutting edge of the tool. As the micro bevel is much smaller than the cutting bevel, it is much faster to maintain and sharpen. ©
A coating of light tool oil will protect the blade from rust and corrosion. ©
For greater protection against rust, chisels can be stored in corrosion inhibiting bags. ©
Always store the chisels in a fitted box or tool roll and use chisel edge guards to protect the cutting edges. ©
Never allow two chisel edges to contact one another as this will cause damage to the edges. ©
Inspect the chisel before use and replace damaged handles immediately. ©