Squaring up wood

It is surprising just how much you can undertake in the way of carpentry projects simply by mastering the most basic skill of cutting timber squarely and accurately to length.

Many different types of saw are available, all designed for specific cutting jobs. In general woodwork, the most commonly used are the handsaw and the backsaw. These are further classified according to the number and shape of their teeth.

Handsaws can be broken down into rip saws, crosscut saws and panel saws, all of which cut at different speeds and with varying degrees of roughness. For the beginner, a panel saw will prove the most useful.

Backsaws can be divided into tenon saws and dovetail saws. Again for the beginner, only the tenon saw is really necessary – use it for cutting across the grain of timber below 150mm x 30mm in size. Other types of saw – such as the coping saw and padsaw – are used for more specialized cutting work: they are described further on in the course.

A solid working surface is essential for quick and accurate saw cutting. If you do not already have a work bench of some sort, an old table covered in 6mm hardboard and used in conjunction with a home-made bench hook should see you through most cutting jobs.

For detailed work at a later stage, you may need to add a vice to the bench. Alternatively, you could invest in a collapsible work bench which serves as a work surface, large vice and drilling rig all in one. Making a purpose-built work bench is covered further on in the course.

Measuring and marking up

Any slight errors made in measuring and marking will multiply when you come to start sawing and may ruin your project. The best way to avoid a mistake is to check every measurement twice.

Having selected the piece of timber to be worked on – the workpiece – inspect it carefully. With a try square, determine which is the straightest adjacent side and edge and mark them in pencil. Always work from these when using any measuring or marking tool – this will ensure that the marks are consistent. A try square is an essential marking tool and costs very little.

For measuring, use a steel rule or boxwood rule where possible: you may need a steel tape on longer pieces of timber or boards, but this is not so accurate.

Mark out distances in pencil, using a ‘vee’– this tells you exactly where you have measured to and is another tip for avoiding errors. Where possible, cut out marks altogether by using the try square and rule.

Where accuracy is essential, mark cutting lines with a sharp knife – preferably a marking knife – not with a pencil. The scored line made by a required distance –

Measure off this distance between the sliding block and the needle point.

Tighten the sliding block so that it just grips the shaft.

Recheck the measurement against your rule.

If you find that the sliding block moved slightly as you tightened it, make adjustments by gripping the gauge and tapping it sharply on the bench. Check the measurement after each tap, until it is exactly right.

To scribe a mark, arrange the workpiece with the gauge nearest you. Make sure that the sliding block is flush against your face side or edge, then roll the gauge towards you until the needle touches the wood. Keeping the gauge at this angle, run it away from you down the workpiece to scribe the line. Avoid applying excessive pressure as you do this: if the needle digs in too far, a wavering line will result.

To scribe a line down the middle of a workpiece, set your marking gauge to roughly half its width and make a mark from the face edge. Make a mark from the opposite edge in the knife is thinner, and therefore more accurate, than a pencil line. Also, it serves to break the outer fibres of the timber, thereby stopping the saw cut from fraying.

As you scribe a cutting line, use the try square to guide you. Your free hand should control the try square without obstructing the marking knife. Keep the stock of the try square flush against the face or edge of the workpiece, with the blade flat on the surface you are marking. The edge of the blade should line up exactly with the points of the vee pencil marks.

When making a straight, 90 degree cut across a piece of timber, mark cut lines all round the workpiece.

Scribing

Scribing with a marking gauge often saves a great deal of laborious measuring and marking. Marking gauges are cheap and really make life easier when marking out. The technique takes a bit of practice to master, so you should experiment on wood offcuts before starting any serious scribing work. To set the marking gauge to the same way, adjust the gauge, then continue making marks from either edge until the two marks coincide. When they do, you have found the middle and can scribe accordingly from the face side or edge.

Solving marking problems

Occasionally, you may come across a piece of timber which is difficult to mark up because of its shape and size.

To find the length of a workpiece longer than your rule or tape, measure a certain distance along it from one end then measure the same distance from the other end. Mark both points and measure between them. Add this to your two original measurements to get the overall length.

If you need to find the centre of this piece, simply divide your third measurement by two and mark off.

Dividing a piece of hardboard into equal strips can become extremely confusing unless the overall width divides exactly. Provided that no great accuracy is called for, you can get round the problem by running your tape or rule across one end of the workpiece and angling it until you get a measurement which is easily divisible by the strips required.

Mark off each division then repeat the process at the other end of the workpiece. Scribe the cutting line for each strip against a rule or straight edge, lined up with these marks. If the board is narrow enough do this with the marking gauge.

Before you start cutting the strips, bear in mind that some wood will be lost during the cutting process – using a panel saw, about 1.5mm per cut. This wastage is known as the kerf. For really accurate work, make allowances for it on each strip.

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