Tool maintenance

No matter how skilled or experienced a craftsman you may be, it is difficult to achieve real excellence unless your tools are properly maintained. As damaged or blunt tools can lead to accidents as well as poor quality work, there are important safety considerations also at stake.

Very little in the way of equipment is needed to keep your tools in good shape but—as with the tools themselves—what you buy should be of the best possible quality. Good storage and proper treatment is then all you need to get the very best out of your equipment.

Equipment list

For maintaining most types of hand tool you need a set of sharpening stones together with lubricants and some files; each a high grade, fine cut tool to suit a particular job. Only occasionally do tools need grinding, and this is dealt with later in the course. All cutting tools (planes, chisels, and the rest) are ground but not honed when you buy them. To put a sharp cutting edge on your tools before they are used, the first items you need are some oil stones.

There are two types of oil stone— natural or artificial. The former is many times more expensive than the latter but is capable of giving a far better edge to your tools. One ploy is to use artificial stones for coarse and medium honing and a natural fine grit stone for the final edge, thus extending the life of the expensive stone quite considerably.

Two types of natural stone are commonly available. Arkansas is available in hard and soft grades, the former being used mostly for the fine honing of instruments and carving tools. The other type, Washita, is more porous and grits range from coarse to fairly fine.

There are two types of artificial stone also: the relatively cheap carborundum, and the slightly more expensive India. Both types are available in three grades—coarse, medium and fine—and you can also obtain a combination form with coarse grade on one side and fine on the other. But unless you are only a very occasional user, separate stones are generally better.

As narrow and curved blades tend to cause stones to wear down unevenly, making the sharpening of broader blades difficult, it is a good idea to keep one side of a stone reserved exclusively for wide blades.

From time to time you may need to sharpen hollow cutters and for these you require special honing stones called slip stones or ‘slips’, available in the same types and grades of grit as the standard blocks but in a variety of shapes.

For lubricant, water is used on coarse natural stone, and fine oil on the others. The best oil is said to be neatsfoot (available from saddlers) but any thin, light machine oil can be used. If necessary, use paraffin (kerosene) to thin this down. Do not use a drying oil such as linseed.

Before ever using a stone, steep it in a bath of the chosen lubricant until it absorbs no more. Store the stone in a purpose-made box to keep it moist and out of harm’s way until it is required.

Always add fresh lubricant to the working surface of the stone during honing operations to keep it moist. Remove dirty oil immediately after use. Periodically scour the surfaces using fine wire wool with some petrol or ammonia (wear gloves).

To avoid excessively localized wear, use the whole surface area of a stone even when you are sharpening narrow bladed tools. When a surface becomes badly worn, it may be possible to restore the evenness by rubbing the stone over the flat surface of a thick sheet of glass or hard stone lubricated with water or paraffin mixed with emery powder. An alternative to emery powder is medium grade grinding paste (available from car accessory shops) but this needs to be thinned out with additional paraffin.

The hardest part of learning the knack of honing is to get the cutting angle right. You can overcome this by ¦ using one or other of the several types of honing guide that are available. These hold the tool at the correct angle and allow you to run it up and down the stone on a roller.

But although very good, these gadgets do require time to set up, and tend to use just the centre of the stone. In the long run, it is perhaps better to persevere with practising the skill of tool sharpening entirely by hand and eye.

To complete the sharpening process it is well worth using a leather strop (an old piece of cowhide) rough side up, which has been soaked with light oil and impregnated with carborundum powder (or fine-grade grinding powder). For shaped tools the strop must be flexible, but for plane irons and chisels you can glue a piece onto a flat piece of wood before the hide is soaked in oil.

Always drag a blade along a strop rather than push it, otherwise you risk damaging the strop itself.

Marking knives

A marking knife needs to be sharp in the same way as any other cutting tool, and a good habit is to hone it to fine sharpness after every job.

A chisel ground knife—which is ground for either left-handed or right-handed use—is one of three types of marking knife. Sharpen it by holding the blade, bevel side down, flat on the stone with the cutting edge lying along the middle. Use the first and second fingers of the free hand to apply pressure on the blade, then twist the blade past the grinding bevel (20°-25°) to the cutting angle of between 25° and 30°.

Maintain this angle, keeping an even pressure on the upstroke and reducing on the backstroke until a burr or wire is formed on the blade. Then turn the knife over, hold it flat against the stone and stroke off the wire in two or three goes. Repeat the operation on successive stones to obtain a really fine cut.

A hollow ground knife, another type, is sharpened in much the same way but as the blade is ground on two sides , it is easier to have the knife at right-angles to the stone.

A variation is the leaf ground knife, which has a curved blade that requires a very different sharpening technique. Hold the knife at a tilt of 25° to 30°, near the far end of the stone, and repeatedly draw the blade towards you, at the same time raising the handle so that the whole curve of the blade is brought into contact with the stone. As you push the blade away, simply reverse the pulling action to cover the arc you have just covered.

All the time keep a firm and even pressure on the knife using the first and second fingers of the spare hand. To remove the wire, run the blade’s reverse edge at right-angles to, and along, the middle of the stone.

Gouges

Gouges can be divided into firmer gouges, which are outside ground, and paring gouges—sometimes called ‘scribing gouges’—which are ground on the inside.

Firmer gouges are ground on the outside edge to 25°. Honing is done to 30°, using an oil stone for the outside edge and a slip stone to remove the wire which forms on the inside.

Hold the gouge against the stone at the correct honing angle and, keeping firm pressure on the blade tip, move the blade up and down the stone rotating it with your wrists as you do so. Make sure that every part of the blade edge comes into contact with the stone.

Remove the wire by holding the gouge on the edge of the bench and rub an oiled slip stone backwards and forwards along the inside channel. Twist the slip from side to side to remove all the wire.

If a strop is used for fine sharpening, wrap it round a piece of wood or do welling to finish the inside.

Paring or scribing gouges are ground to 25° on the hollow side, which is honed to 30° like the firmer gouges. Hold the gouge on a bench and hone the inside edge with a slip of the correct radius. Remove the wire by holding the back of the gouge quite flat on an oil stone. As the tool is moved back and forth, at right angles to the stone, twist it to remove all the wire.

Chisels

Remember the grinding angle is 25° and the honing angle is 30°, and that the chisel must be held absolutely flat against the stone when removing the wire.

If you damage a chisel handle, a replacement should be available from any large tool shop. Simply force this over the tang—the spiked end—of the damaged tool.

Planes

All new planes require honing prior to use—bench planes to 30° from a grinding angle of 25°, block planes to various angles (generally 20° but very occasionally as acute as 121).

But for the best work, you really need to surface the sole which, because of manufacturing distortions, may not in fact be as flat as it seems.

Take a thick sheet of plate or float glass and sprinkle on this some coarse emery powder, mixed with a little water or paraffin (grinding paste.may be used as a substitute). Then, using both hands, firmly rub the plane over the glass in long, oval strokes, a dozen or so times. Wipe the sole clean and inspect it to see if the carborundum has worn away any high spots. If so, keep repeating the process until it is absolutely fiat. Finish off with medium and then fine powder to get a really fine surface.

The cutting edge of special-purpose planes varies considerably from an acute 5° to 10° for router planes, to between 30° and 40° for those sash rebate planes with a cap iron and 40° to 50° for those without. Bullnose rebate planes have a cutting edge to 15°, set with the bevel side up. Router planes must be honed along the edge of the stone (which may mean removing the stone from its box). Remove the wire with the blade dead flat against the surface of the stone.

The blades of moulding planes are honed on the bevel side with slip stones, generally to an angle of between 35° and 40° but occasionally to 30°; some trial and error is therefore necessary to determine which is the correct angle.

Spokeshaves are sharpened in the same way as bench planes. Make a simple device from hardwood or metal to hold the small blades during sharpening should you be unable to find a honing guide small enough.

To sharpen the blade of & hand-held scraper, place it low in a vice (preferably a metalwork one) and use a fine, flat, mill file to draw the edges flat. Remove any file marks by rubbing the blade vertically on a fine oilstone, and the wire by placing the scraper flat against the stone and gently rubbing the blade away from you.

Place the scraper back n the vice and with a burnisher (or back of a gouge), first flatten the edges and then turn them over 10° to produce a finely finished cutting lip.

Stock held scraper blades are ground and honed to 45’. Again, place the blade in a vice and proceed to burnish the edge at 15° to form a cutting lip.

Marking and cutting gauges

Marking gauges need very little maintenance although occasionally it is necessary to remove the stock from the stem in order to touch up the spur with a small, tine file—a saw file is ideal for this. Take care not to scratch the stem as this might damage a workpiece later.

The blade of a cutting gauge is removed for sharpening by first pulling or tapping out the wedge. Hold the blade in a pair of pliers to hone the two bevelled cutting edges (the flat side can be held down firmly against the stone with your fingers).

Occasionally, the stock on a gauge sticks—maybe the result of using badly-seasoned wood, but more likely the result of keeping the tool in a — damp workshop. Ease the stock off the stem and lightly glasspaper the stem until the stock is freed.

If the sliding bar on a mortise gauge is stiff, take the tool apart and use fine emery paper to smooth off the sides of the sliding bar. Wrap the emery paper around a flat piece of metal or hardwood.

Storing chisels and gouges

A good-quality tool is worth storing properly, which means keeping in a dry place. Rust formation is discourse aged by wrapping a tool in an oiled a silk, or by keeping bags of silica gel jn in the toolbox (this is moisture a absorbent and can be recharged by drying it in an oven). id A purpose-made racked cupboard or ie tray can be made for storing your >h chisels, the edges of which are particularly vulnerable to abuse. Take particular care, in use and in storage, to prevent the stem of one chisel from le damaging the edge of another. If it necessary, wrap individual chisels in m oiled cloths or line the partitions of ir your storage box with a soft material. is After storage, and before use, wipe :h the tool down and wash your hands to a prevent oil from being transferred to your workpiece. Do the same if, is during the course of work, you need lg to sharpen the tool you are using.

There is a lot of truth in the saying ‘a craftsman is only as good as his tools’. Dirty, blunt or damaged tools make carpentry work more difficult and can easily ruin a workpiece. And with good quality tools now so expensive, it makes sense to look after those you have got. The previous section on tools described how to sharpen cutting and scribing tools. This section deals with the rest, particularly saws which need quite comprehensive maintenance if they are to work effectively.

Types of saw

Wood cutting saws fall into three basic categories—hand saws, back saws and special saws. The latter type of saws generally always have replaceable blades and consequently need little or no maintenance, but hand saw and back saw categories can be further sub-divided.

The factors most often quoted when maintaining saws or buying replacement parts are saw length, and the size and shape of the teeth. Saw length is measured only along the blade. Tooth size is still commonly measured in the UK according to the number of points per inch (25. 4mm) or teeth per inch. This is generally abbreviated to ppi.

Hand saws measure up as follows: Rip saw: A coarse saw for cutting along the grain of timber. Length is generally 660mm with 5 ppi. Cross cut: The saw for rough cutting across grain and also for cutting joints in heavier joinery work such as roofing timbers. Length is 610mm or 660mm with 7 or 8 ppi.

Panel: A finer saw for accurate cutting across the grain, used also for converting man-made boards and cutting certain joints in lighter joinery work. Length is 510mm or 560mm with 10 ppi. Panel saws with 12 ppi are also available for very fine cutting work in the more expensive ranges.

Back saws are designed mainly for cutting across the grain but they can be used also for cutting along the grain over short measures in jointing work. Tenon saws for general carpentry work are available in lengths of 300mm to 410mm with 12-14 ppi. Tenon saws for cabinet and high class joinery work are more useful for the home handyman and come in lengths of 255mm to 300mm with 16-18 ppi. Dovetail saws, small tenon saws for fine work and dovetailing, are 200mm in length with 20-22 ppi.

Saw teeth

A saw must be able to cut through a piece of timber without sticking and for this reason the teeth are set-alternative teeth are bent outwards to make a cut, or kerf, which is slightly wider than the blade thickness. Higher efficiency is achieved when the blade is taper ground though this is found only on high quality saws. Here, the back edges or sides of the saw are ground down to make the major part of the blade thinner than the edge from which the teeth are cut.

Tooth shapes vary according to the type of saw and the use to which it is put. Saws for cutting across the timber grain have to act like two parallel knives, 1.5mm-2mm apart which can sever timber fibres. In this cutting action, the centre fibres crumble into sawdust which is carried away in the gullets between the teeth.

Rip saws, on the other hand, have teeth like a row of small chisels alternately offset. This configuration enables the saw to shave away a kerf, in much the same way as a plane removes timber. Again, the shavings are carried away in the gullets between the teeth.

Looking after saws

Like any other cutting tool, saws work properly only when they are sharp. Most modern saws are supplied with plastic, slide-on, tooth protectors which are satisfactory guards but can eventually blunt teeth. A far better proposition is to make up your own saw guard from a slotted piece of wood. This can be either screwed to your workshop wall or held on to the saw with strong elastic.

Always keep your saws free from rust and store them in a dry place, covered in a coat of light machine oil. This is especially important if they are being put away for any length of time. If, by mischance, your saw does get rusty, remove the worst rusting with fine wire wool and oil, then finish the process with an abrasive polishing block.

When using a saw never force it and always use firm, even strokes. Remember to check timber, especially second-hand material, for nails and screws before starting a cut. If you do hit a piece of metal, stop sawing and cut the timber from the other side.

Buckled hand saws should be treated by a professional saw doctor —most good specialist tool shops run a saw doctoring and sharpening service. A buckled back saw can sometimes be straightened by supporting it on a piece of wood and tapping the back with a hammer, first at one end and then the other. Hopefully this will force the saw into a slot and eventually straighten the blade. But if the treatment fails then you must seek the service of a saw doctor.

Saw maintenance

A saw that has seen a lot of service, especially if maltreated, will need one or more of the following treatments: topping (to ensure the teeth are level), shaping (to give the teeth the same profile), setting (to offset the teeth at the right angle), and sharpening. Usually a good saw can be sharpened several times before the set is worn away, so sharpen it little and often.

You will need a saw vice or chops to hold the saw—you can make these for yourself —a second cut mill file (used without a handle) and some slim taper saw files. For setting, you will also require a pair of special saw setting pliers.

Saw files are triangular in section and the size you use will depend upon the size of the teeth you are sharpening. Saw points per inch (25.4 mm): 3-5, 6, 7-8, 10-11, 12, 14-16. Taper saw file length: 200mm, 180mm, 150mm, 127mm, 100 or 115mm.

To avoid uneven wear on a file, the face should be just over twice the depth of the saw teeth. When a saw with more than 16 ppi needs sharpening, or a saw with more than 12 ppi needs setting, you should seek the services of a saw doctor. Topping: Set the saw in the chops with the teeth just exposed. Hold the mill file flat along the saw and, using light even pressure, run the file along the saw in a forward direction only until the teeth are all of even height. The file must be kept dead flat and not allowed to rock, so you might need a file clamp. Shaping: With no more than 6mm of saw showing above the chops, place the file firmly in the first gullet so that it follows the correct pitch of the teeth. Grip the file by the handle in your right hand, thumb on top and use your left hand to hold the nose. Shape the teeth by making two full file length strokes across the saw, at 90° to it and parallel with the ground. Repeat the process in each gullet until the teeth are all evenly shaped. Setting: Professionals do this on a saw doctors’ anvil, relying on their eye and experience to set all of the teeth to the correct, even set. However, the amateur is best advised to use a set of saw setting pliers. These have a built-in hammer in the form of a plunger, and an anvil which can be adjusted to any setting between 4 and 12 ppi, which covers most saws.

To use the pliers you place them over the saw, align the hammer in front of the first tooth, then squeeze them so that the tooth is compressed between the hammer and the anvil. This operation bends the tooth to the required set. Continue down the saw, setting alternate teeth, then turn the saw around and set the remainder. Always set the teeth to their original sides—reversing the set may break them off.

It is unlikely that irregularities will occur when using setting pliers but it is just possible. You can remedy the fault after setting is completed by laying the saw flat on a bench and running a fine oil stone down each side of the blade.

Note that some saws, mainly those manufactured in Scandinavia, have specially hardened teeth which are difficult to file and liable to snap when set. These must be returned to your dealer for sharpening and setting. Sharpening: Cross cut saws must have the cutting faces of their teeth levelled to produce knife edges which will sever wood fibres. First fix the saw in the chops, handle to your right, with 6mm of tooth showing. Then top the saw very lightly, to ensure that the tops of the teeth are all the same level. Doing this will reveal a bright speck of new metal—a shiner—on each tooth which will act as a useful guide during the remaining sequence.

Starting at the end opposite to the saw handle, place the appropriate taper saw file in the gullet to the left of the first tooth bent towards you. Swing the file handle to the left until the file makes an angle of 70°-75° with the saw. File only on the push stroke until the ‘shiner’ is reduced by 50 percent—this should take two or three steady file strokes—keeping the file horizontal and maintaining the cutting angle at all times. File the teeth on either side of the file at the same time.

Repeat this operation in each alternate gullet then turn the saw around. This time place the file in the gullet on the right of the first tooth bent towards you and swing the file handle to the right to make the angle of 70°-75°. Once again, work down the saw filing in each alternate gullet. After sharpening, dress the sides with a fine oil stone to remove any burrs.

Rip saws are sharpened in the same way as cross cut saws except that the file is held at right-angles to the saw in order to produce the vital chisel cutting edge on the teeth. Tenon saws are sharpened in exactly the same way as cross cut saws but dovetail saws, which are used mostly for cutting down the grain, should be sharpened in the same way as rip saws.

Boring tools

There is little to go wrong with swing and wheel braces—the standard hand operated boring tools—but a light touch of machine oil on the moving parts will ensure that they stay in good condition. Sometimes the springs in the chuck break, but these can be bought at most specialist tool shops and are easily replaced.

Brace bits

Among the types of brace bit commonly available are the hand dowel bit, centre bit, Jennings-pattern bit, solid centre auger bit, expansive bit and Forstner bit. All are quite easy to sharpen, except the latter which is very expensive and usually used only by professional cabinet and pattern makers. Conventional bits generally have either a screw centre or centering point, one or two outer spurs and one or two cutter blades. The outer spurs cut the circumference of the hole while the cutters lift out the waste timber.

To sharpen a brace bit you will need a 10mm medium cut flat needle file. Stand the bit on its centre on a piece of scrap wood and following the original angle, file down the cutters until a sharp edge is formed. The inside of the spurs should also be lightly filed to give a good cutting edge. Subsequent burrs on both cutters and spurs can be removed with fine oil slip stones. But on no account should you file or overhone the underside of a cutter or the outside of a spur.

Should you have difficulty holding the bits, they can be held in a metal-work vice protected by fibre or soft metal jaw liners.

Twist and flat bits

Proprietary tools for sharpening the twist bits used in. power drills are produced by some of the major power tool and drill manufacturers. They can also be sharpened by hand on a grinding wheel—a technique covered further on in the course.

Spade or flat bits, too, are designed for use in high speed electric drills. To sharpen one, simply place it vertically in a vice and lightly file the top cutting edges to the original angle. Do not file the sides of the flat bit as this would unbalance it.

Hammers

Hammers should always be kept clean and free of chips and scratches. When using a hammer to assemble a glued frame or carcase, remember to remove any traces of adhesive from the head or handle before it sets.

A clean hammer head is less likely to slip off a nail head, so inspect it before use and if necessary give it a polish with fine emery cloth. A good idea is to keep a piece of emery cloth stapled to one le.g. of your bench where it will be ready to hand for this and similar purposes.

The heads of wooden handled hammers sometimes become loose. To cure the problem hold the hammer vertically and thump it, handle down, on a block of wood until the head is firm on the handle. Then knock metal wedges into the wood in the eye of the head until the wood fills the whole of the eye. These wedges are available from tool shops in various sizes to suit most types and sizes of hammer.

Should a hammer handle become split or broken, it must be replaced. Replacement handles in various sizes are also readily available but make sure you buy the correct type and size for the hammer you are mending. The best, probably, are made from ash or hickory.

Cut off the handle just below the head and place the head in a metal-work vice (if you must use a woodworking vice protect the jaws with scrap wood). Working between any metal wedges that may already be there, drill out as much wood as you can. Then knock out the remainder, together with the wedges, using a hammer and a large drift.

Take the new handle and shape the end to fit tightly into the eye of the head with a wood rasp and glasspaper. Then use a tenon saw to cut a slot in the handle to about two-thirds the depth of the head. At the same time prepare from scrap hardwood a suitable wedge. a To ensure a tight fit wrap the handle I in a polythene bag, excluding as much I air as possible, and leave it overnight e in a fridge. When it is ready, pop the I hammer head into a pan of boiling water for 10 minutes. These two processes shrink the handle and expand the head. Knock both com- ponents together with another hammer remembering to protect the handle with a piece of waste wood, then drive in the wooden wedge.

Finally, drive in two proprietary metal wedges at right-angles to the e wooden wedge and clean off tne head s with a coarse sanding disc. f

Screwdrivers e Screwdrivers for use with slot head screws become worn after a time, in s which case they are liable not only to e damage the screw, but also to slip and e damage the workpiece. Place any such e screwdriver, tip uppermost, in a r metalwork vice and file the tip square with a fine flat file. e Pump action (’Yankee’) screw– drivers tend to become clogged. Deal with this by cleaning the visible parts I of the pump mechanism with 000 grade y wire wool and lubricating it with a e few spots of fine machine oil. On a occasions the spring or ratchet on ¦, these tools wears out. In this case the a manufacturers operate an overhaul service at reasonable cost. e e Cramps and Clamps

Always remove adhesive from cramps, Q preferably before it sets. When the e screw on a cramp becomes stiff, clean e it with grade 0 wire wool and paraffin a (kerosene) and then apply a few drops of light machine oil.

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