You may be proficient at using saws, planes and other tools for cutting and shaping wood, but for a perfect result you must be able to mark up with precision.
And for that you will need a number of special tools.
Carpenter’s tools are all designed for specific purposes and to use marking and measuring ones successfully the wood must be square. If not, this could be the reason why,for example, lines around timber don’t meet where where they should. Never make the mistake of thinking that timber bought ready-planed is necessarily perfectly square. Always check for yourself.
The timber could also be warped, or its actual size may be different from the nominal size you ordered, and this could result in badly fitting joints.
Marking up square or.
– rectangular-sectioned timber is relatively straightforward when the right tools are used. Marking up mouldings full of lumps and bumps is a different matter. All you can do here is draw a line on whatever raised and flat surfaces are available.
There are some mistakes or imperfections you can easily correct. A common cause of error, for instance, is to switch between imperial and metric measurements. Don’t. Decide on one system and stick to it. For while some conversions are accurate, others may have been rounded up or down.
If a marking knife or the spur of a marking gauge leaves a ragged score mark, check to see if the knife or spur is sharp. If it is, you are probably digging too deeply into the wood. The best way to make a deep line is to build it up by going over it two or three times rather than trying to do it in one go. For marking across the grain, a cutting gauge is purpose-built and will avoid the problem.
Flexible tapes are frequently marked off in both metric and imperial gradations. The tape – up to 5m (16ft 3in) long – is pulled from a spring-loaded holder and retracts automatically when released; some tapes can also be locked in any position. At the end of the tape is a tab which you hook over or butt up against whatever you are measuring. Carpenter’s rules These are more accurate than tapes because they are not flexible and can be laid flat on a surface. They normally give both metric and imperial measurements up to 1 m (3ft 3in). They are made from boxwood, steel or plastic and many are hinged so they can be folded up. Straight-edges
These are precision-made plain metal bars up to 2m (6ft 6in) long, with one bevelled edge, which is used (bevel up) for drawing straight lines. Straight-edges can also be used to check ihe flatness of a surface.
Try-squares, combination squares and sliding bevels A try-square is used for drawing and checking right angles by placing the wooden or plastic stock against the timber. The metal blade is usually between 150mm and 300mm (6in and 12in) long. Metal-stocked engineer’s squares are also available – they are more accurate and more expensive. A combination square is a versatile measuring tool for both 90° and 45° angles, and also incorporates a spirit level for checking the true vertical.
A sliding bevel is designed to measure awkward angles. The stock can be moved along the blade, then locked in position so that the angle can be transferred to the timber. Carpenter’s pencil and marking knife A pencil is useful for shading waste areas (a sensible precaution against mistakes) and for making marks that must be.’ : cleaned off so they don’t show on the finished job. The traditional carpenter’s pencil is rectangular in section, but you can use an ordinary HB pencil sharpened to a chisel point.
Before sawing, chiselling or planing, it’s best to use a knife to draw the guide-lines. This makes a thinner, more accurate line than a pencil, and also, by cutting through the surface fibres of the wood, helps to give the cut a neater finish. Knives with a specially angled cutting edge are manufactured specifically for marking, but any sharp craft knife or replaceable-blade knife is suitable.
Marking and mortise gauges
You can use a marking gauge to mark a line parallel with and close to the edge of the wood you’re working on. It has a wooden block, called a stock, which you can fix with a thumbscrew at any point along the wooden shaft so it is a given distance from a sharp metal spur. You steadyone end of the wood against a bench-hook or the edge of the bench, and press the other end into your stomach; then, holding the gauge’s stock against the edge of the wood, with the spur angled so it points away from the direction of travel, slide the stock along so that the spur is dragged lightly at an angle along the surface.
A cutting gauge, with a blade instead of a spur, is ideally to be preferred for marking across the grain.
The mortise gauge is like a marking gauge but has two spurs, one fixed and one movable, allowing you to score a pair of parallel lines. It is mainly used for marking mortise-and-tenon joints, but by retracting the movable spur into the stock it can be used as an ordinary marking gauge instead. It is set in much the same way as a marking gauge, but before you fix the stock in relation to the movable spur you should set the latter at the correct distance from the fixed spur.
Combined marking and mortise gauges are also available. These have two spurs – one fixed, the other movable – on one edge, and a fixed spur on the opposite edge.