In the Engineering workshop you will use a variety of hand tools. In this chapter we will look at:
Files are used in the workshop for rough waste removal as well as fine finishing of material surfaces. The illustration below shows the two main parts of a file.
The tang of a file is not hardened during manufacture. The tang can be quite sharp and may cause injury to your hand if you use a file without a handle. Never use a file without a properly fitted handle on the tang.
The body of a file is hard and brittle. When a file is manufactured the teeth are cut into the face of the body which is then hardened and tempered. The size of a file is usually given as the body length. Some files have single cut teeth and others have double cut teeth for faster waste removal. Files are available in various shapes, sizes and grades. The most common grades are smooth, second cut and bastard.
Bastard files are quite coarse and are used for roughing down and for fast removal of waste material on softer metals.
Second cut files are used to produce a smoother finish after roughing down with a bastard file. They are also suitable for roughing down harder metals.
Smooth grade files are used for finer finishing work. They produce a smoother finish than second cut files.
These general purpose files have double cut teeth on the faces and single cut teeth on both edges. They taper toward the point and can be used on both flat and convex surfaces.
Hand files are also general purpose files that have double cut teeth on the faces. They are parallel files with single cut teeth on one edge only. The edge without teeth is often called the safe edge.
Half round files have one flat face, a curved back and, like a flat file, the shape tapers toward the point. Half round files are used to file round holes and concave surfaces.
Mill files (or millsaw files) generally have single cut teeth on both faces and usually have one rounded edge with single cut teeth. They are used for sharpening circular saw blades and fine work such as draw filing and filing turned surfaces on the lathe.
Warding files are thinner than other files, rectangular in section, parallel in thickness and tapered toward the point in the width. They are generally used for filing narrow slots and small keyways.
Small triangular files (slim taper files) are often used to sharpen hand saws. They have single cut teeth and some have slightly rounded corners.
Larger triangular files are sometimes called three-square files. They have double cut teeth and relatively sharp corners. Triangular files are used for filing out acute angled corners greater than 60°.
Round files (or rat tail files) are circular in section and are used for enlarging holes and filing fillets. They have spiral cut teeth and are generally tapered.
Square files are square in section and they are usually tapered. Square files are used for filing keyways and for smoothing or enlarging square and rectangular holes. Larger square files generally have double cut teeth.
A file brush (or file card) which has stiff wire bristles, should be used to clean waste material out of the file teeth. The file brush should only be used across the file in the direction of the teeth to avoid unnecessary wear of both the brush and the file.
If the particles of metal (pins) are firmly wedged between the file teeth, they can be removed with a piece of soft metal. The pins should be pushed across the file, working in the direction of the teeth.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /r /f ][ If you want to file narrow slots or small keyways, what type of file would you use? ][ * Flat file. ][ Warding file. ][ * Mill file. ][ * Square file. ][ The warding file is made for just this purpose. ]]
[[ mc /r /f ][ A rat-tail file is also known as a: - ][ Round file ][ * Square file. ][ * Bastard file. ][ * Half-round file. ][ Round like a rat's tail. ]]
[[ mc /r /f ][ The narrow, sharp pointed part of a file that all files possess is called the: - ][ Tang. ][ * Handle. ][ * Rats tail. ][ Taper. ][ The tang is the narrow part that a file handle fits over. ]]
[[ mc /f ][ In order from smoothest to coarsest, file grades are: - ][ Smooth, Second cut, Bastard. ][ * Smooth, Bastard, Second cut. ][ * Bastard, Second cut, Smooth. ][ * Bastard, Smooth, Second cut. ][ Bastard is the coarsest; You can work out the rest. ]]
Various types of hammers are used in the engineering and metal trades. The three most common ones are illustrated on the following page.
The engineers hammer or ball pein hammer is used for heavy percussion work such as cutting metal with a cold chisel. The ball part can be used for various burring and rivetting operations.
Cross pein hammers are general purpose hammers used mainly for lighter work than the engineers hammer. The cross pein can be used in corners that are difficult to work in with the face of a hammer.
These soft faced hammers are used for any application where a hard faced hammer might damage the work.
Before leaving this page, think of what you've just been reading, and test yourself with this question.
[[ mc /f ][ You need to tap a steel pin into an aluminium block. What do you reach for? ][ * Your engineer's hammer. ][ Your cross pein hammer. ][ * Your nylon faced hammer. ][ Your cross pein will do the trick. ]]
Chisels that are used for cutting metal are often called cold chisels. During manufacture they are forged to the required size and shape, then hardened and tempered.
The flat cold chisel can be used for purposes such as chipping flat surfaces, cutting thin sections of metal, splitting nuts and cutting off bolt heads when they can’t be removed by other means.
The illustration below shows the cutting angle of a chisel which is formed by grinding two equal bevels. The included angle is the cutting angle or angle of the cutting edge.
The cutting angle can be varied to suit the metal being cut. A more acute angle can be used on softer metals. An average angle suitable for mild steel is around 65°. Angles of 55° and 75° are used for brass and cast iron.
The cross cut cold chisel is a special purpose tool used for cutting keyways and grooves that require a flat bottom and walls that are right angled to the bottom. The blade is wider at the cutting end to prevent the chisel from jamming in the groove.
Cold chisels are sharpened on a grinding wheel. Hold the chisel lightly against the grinding wheel and move it back and forth to ensure even grinding. Avoid overheating the chisel by frequently quenched it in water. Overheating results in loss of temper in the steel and the chisel will be too soft to cut effectively.
Grinding wheels must be in good condition. The grinder must be fitted with wheel guards to protect your hands and clear spark guards should be positioned over the grinding area. Always wear eye or face protection, restrain long hair and keep your hands clear of the abrasive wheels.
Before leaving this page, think of what you've just been reading, and test yourself with this question.
[[ mc /f ][ When sharpening your chisels, how do you prevent them from going soft? ][ Cool them by dipping in water regularly. ][ * Sharpen one face at a time. ][ * Sharpen from the body towards the tip. ][ * Don't lose your temper when sharpening them. ][ The usual practice is to dip repeatedly in water while sharpening them. ]]
[[ mr /f ][ What safety issues must be addressed when sharpening chisels? ][ Guards need to be fitted to the grinding wheel. ][ Eye and face protection should be worn. ][ * No-one else should be nearby when sharpening chisels. ][ Long hair needs to be restrained. ][ As long as everyone is wearing appropriate PPE, others can be nearby. ]]
The prick punch illustrated below is used when marking out, to permanently and accurately witness mark centres and lines with a small indentation (prick). The point angle of a prick punch is 60°.
The centre punch shown below is used to make a conical indentation in the surface of metal, to help a drill to start accurately when drilling a hole. The position of the centre can be accurately marked with a prick punch before centre punching. The point angle of a centre punch is 90°.
The pin punch illustrated below is used to drive metal pins when parts are being assembled or dismantled. It can also be used to punch small rivet holes in light gauge sheet metal.
Before leaving this page, think of what you've just been reading, and test yourself with this question.
[[ mc /r /f ][ What type of punch is best suited to marking medium-gauge sheet metal just prior to drilling? ][ A prick punch. ][ A centre punch. ][ A pin punch. ][ The centre punch is made for just this purpose - to centre the drill on the job. ]]
The illustration below shows a basic steel rule that would be used in most school workshops. Basic steel rules are graduated in millimetres. Some engineers rules are graduated in half millimetres and are available in a range of lengths from 150 millimetres to 2 metres. Steel rules are used for making accurate measurements and are handy straightedges. Keep steel rules clean and avoid damage to the edges at all times.
The scriber is used to mark lines on metal surfaces. It is made from tool steel that has been hardened and tempered. The fine point can be lightly ground and then finished on an oilstone.
The engineers try square is made from steel and is available in a range of sizes. A try square is used for testing the accuracy of surfaces that must be at right angles to each other. It is also used for setting work at right angles and as a guide for marking lines at right angles to edges or other surfaces.
The engineers square is a precision tool which must always be used and treated carefully. Make sure you don’t bump the square against other tools on the bench or use it for purposes other than those mentioned above.
It should be stored carefully and coated with a light film of oil or anti-rust compound when not in use.
Spring dividers are used for scribing arcs and circles, dividing lines and circles into equal parts, stepping off equal distances and transferring measurements from the rule to the job. Always keep the divider points sharp and equal in length.
Calipers are used for measuring the diameter of a shaft, a hole or a straight line distance between two surfaces. Always adjust the caliper jaws to the surfaces with the correct feel, without play (too loose) and without pressure (too tight).
The firm joint calipers illustrated below can be lightly bumped to make fine adjustments to the setting.
Outside calipers are used to measure outside diameters.
Inside calipers are used to measure the diameters of holes.
The spring calipers shown below are used for the same purposes as firm joint calipers.
The cylindrical spring at the top of the calipers tensions the legs and adjustment is made by turning the set screw nut.
Spring calipers can usually be set to size with the correct feel more quickly than firm joint calipers.
When calipers are set, the measurement can be taken with a rule or other graduated measuring device.
Often referred to as jenny or odd leg calipers, one leg is similar to firm joint inside calipers while the other leg has a scribing point. Jenny calipers are used to mark lines parallel to an edge and for centering circular work.
The basic engineers combination set consists of a square stock, protractor stock, centre square stock and an interchangeable blade or rule that fits all three stocks.
The combination square can be used to test and mark 90° and 45° angles. The adjustable blade allows the combination square to be used as a depth gauge or to mark lines parallel to an edge.
The protractor can be set to angles between 0° and 180°. It is used for both marking out and setting work.
The centre square is used for drawing diameters and locating centres on round work.
The square stock and protractor stock usually contain small levels which are handy for setting up some types of work.
The parts of the combination set are precision tools which must be used and stored carefully to avoid damage which may affect their accuracy.
The bevel gauge is used for marking out, testing angles and transferring angles from one part of the work to another. If a bevel gauge is to be set to a particular angle, it must be set using a protractor such as the one shown above.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /f ][ What instrument are you most likely to use to measure the inside diameter of a piece of pipe? ][ Calipers. ][ * Steel rule. ][ * Dividers. ][ * Engineers Square. ][ Inside calipers are designed for this purpose. ]]
[[ mr /f ][ You have to make a metal plate with five equal-length edges and five equal angles. What tools should you use to ensure the angles are all equal? ][ A bevel gauge. ][ A protractor. ][ * An engineers square. ][ * Spring dividers. ][ * A combination square. ][ A protractor to measure the first angle, and a bevel gauge to transfer it around the plate. ]]
[[ mr /r /f ][ What size angles can be marked out using a combination square? ][ 450 ][ 900 ][ 1350 ][ * 1200 ][ * 600 ][ Combination squares can mark out angles of 450 and 900, and the sum of them - 1350. ]]
Hacksaw frames are adjustable to suit the various lengths of hacksaw blades available. The hacksaw shown on the right has a tubular steel frame and a movable handle.
Some older types have telescopic frames which lock into positions to suit the various blade lengths. Most hacksaw frames allow the blade to be held in four different positions. For example, the blade can be fitted sideways when making long cuts. With the blade in this position the length of cut is not limited by the hacksaw frame.
Hacksaw blades are manufactured with various numbers of teeth per 25mm (inch) to suit a range of uses. The illustration below shows blades with 32, 24 and 18 teeth per 25mm.
The most common blade length is 300mm. Other blade lengths such as 250mm and 350mm are sometimes available.
Generally, a fine blade is used for cutting thin tube, sheet metal and thin sections. Coarser blades are more efficient on solid or thick sections.
Hacksaw blades are made either from low carbon steel or high speed steel. High speed steel blades are brittle and can break easily with incorrect use. Some hacksaw blades are hard in the area of the teeth and soft on the back. This allows the blade to flex, probably cracking across the hardened part but not breaking completely.
Before leaving this page, think of what you've just been reading, and test yourself with this question.
[[ mc /r /f ][ What type of blade (teeth per 25mm) is best suited to cutting heavy gauge sheet metal? ][ * 32 teeth. ][ * 24 teeth. ][ 18 teeth. ][ The heavier the metal, the coarser the blade, so 18 teeth would be best. ]]
The size of a standard screwdriver is usually given as the length and width or diameter of the shaft, for example 200x8mm or 80x4mm. The type of screwdriver selected will depend on the work being done and the type of screw being used.
Care must always be taken to select a screwdriver that fits snugly into the slot in the screw head, to avoid damage to both the screwdriver and the head of the screw.
General purpose or standard screwdrivers, are available in a range of sizes for screws with straight slotted and Phillips heads.
Standard screwdrivers are manufactured with the shaft embedded in the handle which is usually made from a tough plastic material.
If it is necessary to use a hammer on a screwdriver handle, a tang-through type should be selected. These screwdrivers are manufactured with the shaft protruding through the handle so the hammer strikes the end of the steel shaft, not the handle.
These screwdrivers are used mainly in the woodworking trades. In the metal trades, patternmakers use woodwork tools and machines to make wooden patterns from which moulds are made. Molten metal is poured into moulds to make castings. Ratchet screwdrivers allow a screw to be driven or withdrawn in a continuous, alternating motion without altering your grip on the handle.
Driver bits for some types of ratchet screwdrivers and power tools are available for the full range of screw sizes and types including hexagonal heads.
The offset screwdriver illustrated below is used for turning screws in positions that would be inaccessible to other drivers. It has driver tips at each end which are set at 90° to each other.
By alternating ends you can make quarter turns of the screw in very tight situations where a bigger swing is not possible.
Before leaving this page, think of what you've just been reading, and test yourself with this question.
[[ mc /f ][ What types of screwdrivers are designed to be hit with hammers? ][ * All of them - the handle is toughened plastic. ][ Only those with the shaft passing right through the handle. ][ * Only those that say that the plastic is heat-toughened. ][ * Only those with wooden handles - they won't shatter like plastic. ][ If the steel isn't visible from the top of the handle, then don't hit it. ]]
Spanners are used in the workshop for a variety of purposes such as assembly work. Other uses include setting, adjusting and maintaining tools, equipment and machines. The most appropriate spanner should always be selected for a particular job. It should fit the nut perfectly and allow the job to be done quickly and efficiently.
Open end spanners have a u-shaped opening at each end which fits neatly across the flats of a nut or bolt head of that particular size.
Ring spanners have sockets at each end which grip all faces of the nut. They are useful when working in confined spaces where a full swing is not possible.
Adjustable spanners are often called shifting or crescent spanners. They have a movable jaw which can be adjusted to fit a range of nut sizes. You must always be careful to fit the jaws as tightly as possible to minimise damage to the nut. Use an adjustable spanner only where it is not possible to use the correct sized fixed spanner.
Sockets or socket spanners provide a positive grip similar to ring spanners. Interchangeable sockets are fitted to a ratchet handle which provides the leverage required.
Ratchet handles (or wrenches) used with sockets provide the quickest action of all hand operated spanners. The ratchet action allows the handle to be rotated forward and backward, tightening or loosening the nut without lifting or repositioning the spanner.
Combination spanners are versatile tools which have an open end spanner at one end and a ring spanner at the other end.
Stillson wrenches are used for gripping and turning threaded pipes. They can be adjusted to fit a range of pipe diameters. Hardened teeth on the jaws grip the pipe as it is being turned.
Pipe wrenches are also used for gripping and turning pipes. The type illustrated is adjusted to size by relocating a pivot pin in a series of adjustment holes.
Allen keys (or hexagonal socket wrenches) are used to turn screws that have hexagonal sockets in the head.
Tension wrenches can be set to a specific tension which is indicated in use by an audible click. This helps to prevent over-tightening of nuts which can damage and even strip threads. The tension wrench is fitted with the appropriate socket for the job.
Spanners and wrenches should be kept free of dirt, grease and corrosive substances. Moving parts should be cleaned and lubricated occasionally.
Part of your maintenance procedure should be to use spanners and wrenches only for their proper purpose. Never apply excessive pressure and always make sure the spanner is fitted correctly to the job.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /f ][ What's the best spanner to use on a tight nut? ][ A well-fitting ring spanner. ][ * A well-fitting open-end spanner. ][ A well-adjusted adjustable spanner. ][ * A stillson wrench. ][ The ring spanner is always the preferred solution if you can get it on the nut. ]]
[[ mc /f ][ What type of spanner would you use to wind a pipe into a threaded fitting? ][ A stillson wrench. ][ * A ring spanner. ][ * An open end spanner. ][ An allen key. ][ The stillson wrench has teeth designed to grip the outside of smooth pipe. ]]
Combination pliers are general purpose tools used for gripping small flat or round objects and bending and cutting wire. The side cutters should only be used for cutting soft wire. The wire cutters (or joint cutters) should be used to cut harder wire.
Snipe nose pliers (or long nose pliers) are used for gripping small objects in confined spaces where other pliers may be too cumbersome or may obstruct your view.
Multi-grip pliers (often called multi-grips) are designed to allow the pivot to be moved to several different positions. This gives a much greater range of jaw opening and enables parallel gripping by the jaws in a number of different positions. The long handles provide additional leverage which allows multi-grips to grip tighter than most other pliers.
Lock-grip pliers (usually called vice grips) have a compound lever system which can apply considerable pressure at the jaws and allows the jaws to be locked on to the job. The jaw opening is adjusted to fit the object using the set screw at the end of the upper handle. When the handles are squeezed together the jaws lock onto the job. A release lever is located in the lower handle.
Circlip pliers are used for inserting and removing circlips. The points of the pliers are placed inside the rings of the circlip which is depressed or expanded. Straight and bent circlip pliers are available for inside and outside circlips.
Diagonal cutting pliers are used for cutting soft wire and other soft materials. They are commonly called side cutters.
Pincers are used mainly by pattern makers for pulling out small nails and staples and cutting soft materials. The surface of soft material should be protected when a lever action is used to remove nails.
Tinsnips are handy in the engineering workshop for cutting shims and sheetmetal which could be used for purposes such as packing when setting up work in machining operations. They are also handy for cutting gasket material.
Straight tinsnips, as shown below, are general purpose cutting tools. Other types such as small jewellers snips, heavy duty aviation snips and shears may also be useful in the engineering workshop. Curved snips are generally available in most of the different types of snips.
Pliers and tinsnips should be kept free of dirt, grease and corrosive substances. Moving parts should be cleaned and, if necessary, lubricated occasionally. Part of your maintenance procedure should be to use these tools only for their proper purpose and never apply excessive pressure when using the tool.Tinsnips should never be used to cut wire because it is likely to gap the cutting edges.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /f ][ Side cutters are more correctly known as: - ][ Diagonal cutting pliers. ][ * Combination pliers. ][ * Snipe nose pliers. ][ * Circlip pliers. ][ Diagonal cutting pliers are also known as side cutters. ]]
[[ mr /f ][ What is the purpose of the screw adjustment in the handle of a pair of vice grips? ][ It adjusts the jaw opening. ][ It adjusts the amount of grip applied. ][ * It prevents the grips from breaking small objects. ][ * It releases the grip once the job is finished. ][ The screw adjustment changes the jaw opening and the amount of grip applied. ]]
[[ mr /f ][ How do you maintain tinsnips? ][ Keep them clean and free of corrosive substances. ][ Lubricate them occasionally. ][ * Sharpen them by cutting lengths of wire. ][ Only use them for their intended purpose. ][ Cutting wire with tinsnips can put dents in the cutting edge, ruining them for their intended use. ]]
Taps are hardened tools used for cutting internal screw threads. The illustrations which follow show the three types of taps required to thread a blind hole. A blind hole is not drilled all the way through the material.
Taper taps are used to start the thread. They usually have a seven to nine thread lead. This means that the thread on the tap is ground back to taper the teeth over seven to nine threads.
Intermediate taps are used after the thread has been started with a taper tap. These taps usually have a three to five thread lead.
Bottoming taps are used to finish the thread in a blind hole. They have a one to one and a half thread lead and are often called plug taps.
Taps are held in tap wrenches so you can apply the rotational power which is necessary for the threading operation.
Bar type tap wrenches are available in a range of sizes to suit different size taps. The square end of the tap is held between V-shaped jaws which are hardened and tempered. You can adjust and tighten the movable jaw by turning one of the knurled handles.
T type tap wrenches are designed to be used with smaller taps in positions where you can’t rotate the bar type in a full swing.
The tapping hole should be smaller than the tap. The exact drill size required can be found from a tapping drill chart. However, for most metric threads a reasonable approximation is given by the following formula:
Tapping hole = D - p
D is the outside diameter of the tap and p is the pitch. Pitch is the distance from a point on one thread to a corresponding point on the next, measured parallel to the axis of the thread.
Always use a suitable cutting oil when you are tapping and back off the cutting action when you feel resistance, every half turn or so, to break off the waste material. Taps are very hard and therefore very brittle. They will break if you apply too much pressure, particularly if you allow the waste to build up.
Button dies are manufactured from high quality chromium tool steel. They have three relieved segments of a threaded hole which cut external screw threads on round bar. Most button dies have the size and pitch stamped on them, e.g. 4.5mm x 0.60mm. This means that the outside diameter is 4.5mm and the pitch is 0.60mm.
Dies are held in a die stock which is often called a die holder. A typical die stock is illustrated below. To mount the die in the die stock, you rotate the side screws anticlockwise until you can insert the die into the stock with the V in the die located on the centre screw.
The centre screw should be just finger tight. Make sure you enter the die into the stock with the starting side of the die facing outward, then tighten the side screws onto the die until they are also just finger tight. The screws should have entered the dimple holes on the edge of the die, retaining the die in the stock. Now you can tighten the centre screw into the V slot, then tighten the side screws with a screwdriver.
File a small bevel on the end of the rod to help start the thread. Hold the die stock with both hands near the die and press the starting side of the die firmly down on the work, making sure that the die is square to the rod. Apply cutting oil and turn the die clockwise, backing off to break the waste when you feel resistance.
When the thread is started, grasp the die stock by the handles. Use a steady forward and backward action to continue cutting the thread, advancing only a little at a time. Once the thread has started properly, the die will draw itself into the work.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /f ][ In what order would you use these taps to cut a threaded hole? ][ Taper, intermediate, bottom. ][ * Bottom, intermediate, taper. ][ * Taper, bottom, intermediate. ][ * Taper, bottom, water. ][ Taper taps start the job and bottom taps finish it. ]]
[[ mc /f ][ What should you do to a piece of rod to make it easier to cut a thread onto it? ][ File a small bevel on the end of it first. ][ * Coat it in cutting oil from end to end. ][ * Keep dipping it in hot water to keep it soft. ][ * Clamp it in a pair of vice grips. ][ A small bevel will assist the die to start the thread cut. ]]
[[ mc /f ][ Why should you occasional wind taps and dies backwards? ][ * To keep them cool. ][ * To keep them covered in cutting oil. ][ To clear waste material from the cutting face. ][ * To stop the cutting tap or die from binding on the metal. ][ Waste material breaks away when you turn the tap or die backwards. ]]
Chipping hammers are used to remove slag and spatter from the weld area. Make sure you wear eye protection when you use a chipping hammer.
Wire brushes are used to prepare the weld area by removing rust and other contaminants that could affect the quality of the weld.
Before leaving this page, think of what you've just been reading, and test yourself with this question.
[[ mc /r /f ][ When working around welding equipment, and with welders hand tools, what is the most important piece of safety equipment? [ rcl ][ Eye protection. ][ * Hearing protection. ][ * Dust protection. ][ * Electrical shock protection. ][ Eye protection is an absolute must. ]]
In the metal and engineering industries, patternmakers use a range of woodwork tools and machines to create wooden patterns from which moulds are made. Molten metal is poured into these moulds to make metal castings.
Planes are used to straighten, smooth or shape faces and edges of timber. The photograph below shows a typical plane and its adjustments.
You turn the adjusting nut to increase or decrease the depth of cut and move the lateral adjustment lever to set the blade parallel to the sole of the plane.
The illustrations below compare the relative size of the smoothing plane and the jack plane.
Smoothing planes are used mainly for fine finishing work. Length is in the range 230mm to 260mm and blade widths are 45mm, 50mm and 60mm.
Jack Planes are general purpose planes that can be set for fine finishing work as well as for fast waste removal. Length varies from 350mm to 380mm and blade widths are 50mm or 60mm.
The illustrations below show a selection of common wood chisels. Handles are made from either wood or plastic. Wooden handles usually have steel or brass ferrules fitted to help prevent splitting. Chisels should be kept sharp, free from rust and glue and always stored in a way that protects cutting edges.
Firmer chisels are general purpose chisels with a rectangular blade, used mainly for heavier bench work.
Bevelled edge chisels are used for fine work and where the bevelled edge allows the chisel to fit into acute angles.
Mortice chisels have a thick blade and are used for the heaviest work where the waste needs to be levered out.
Gouges are similar to chisels, except that the blades are curved and are used for general carving, and grooving.
Wooden mallets of the type shown below are sometimes called carpenters mallets or joiners mallets.
Mallets are used to strike chisels when removing waste material in shaping operations. The mallet is preferred to a hammer because it is less likely to damage the chisel handle.
Spokeshaves are used to smooth curved edges. They have a blade and cap iron similar to a plane and work in much the same way.
Flat faced spokeshaves are used for smoothing convex edges and round faced spokeshaves are used for smoothing concave edges.
Rasps are used for rough shaping of wood. They are usually available in three different grades.
Half round bastard rasps are generally used for the roughest work. Regular cabinet rasps and smooth cabinet rasps are used to produce a progressively finer finish.
Patternmakers also use files for shaping and smoothing, particularly half round files which are sometimes called cabinet files. You must never use a rasp or a file without a properly fitted handle on the tang.
Grinding becomes necessary when the cutting edge is chipped or gapped or when the edge is worn and you find it hard to sharpen on an oilstone. Check that the tool rest on the bench grinder is set to give a grinding angle of around 25º.
Always hold the blade lightly against the grinding wheel and move it back and forth carefully so the grinding angle will be even. Quench the blade frequently in water.
If you don’t cool the blade a bluish colour will appear on the cutting edge as it overheats. This will result in loss of temper of the steel and you will need to sharpen the cutting edge more often.
Honing the cutting edge is done on an oilstone. The photograph below shows a typical aluminium oxide oilstone with a fine abrasive surface on one side and coarse on the other.
Light oil is used on the stone to float off particles of metal and to prevent clogging of the abrasive surface.
Place the blade flat on the oilstone with the grinding bevel facing up and rub the blade back and forth several times to remove any grinding burrs.
Turn the blade over and locate the 25° grinding angle on the flat surface of the stone. Raise the blade about 5° to give a sharpening angle of 30° and then rub on the stone using a figure eight motion until a fine burr forms on the cutting edge.
Turn the blade over and rub it lightly to remove the burr. Plane blades that are ground perfectly straight can be rubbed back a little on the corners to avoid leaving marks on the planed surface.
Planes and chisels should be kept sharp, free from rust and glue and always stored in a way that protects the cutting edges.
Before leaving this page, think of what you've just been reading, and test yourself with these questions.
[[ mc /r /f ][ What is the preferred sharpening angle for wood chisels and plane blades? ][ * 150 ][ * 200 ][ 250 ][ * 300 ][ The preferred angle is 250. ]]
[[ mr /f ][ Why do you put light oil on the surface of an oilstone when sharpening cutting edges on it? ][ It floats waste particles away. ][ It prevents clogging of the stone surface. ][ * Because the stone won't work if it's dry. ][ * It prevents the stone from overheating and cracking. ][ The oil floats waste away and prevents clogging. ]]