The following is excerpted from Robert Wearing’s “The Essential Woodworker.”
The aim of the following exercises is to produce full-length, full-width shavings. The first exercise will show whether the reader is achieving this aim.
Grip in the vice, edge upwards, a piece of clear softwood about 300 x 75 x 25mm (12 x 3 x 1in.). With a woodworker’s soft pencil draw a line down the middle (Fig 29). Using a sharp, well-adjusted plane, plane a full-length, full-width shaving. The pencil mark should be completely removed. Mark the wood with the pencil and plane again, repeat this for ten shavings. If a trace of the pencil mark remains, begin the count again. After ten successful attempts have a brief rest then cut a further ten. This is the technique of planing when the wood is narrower than the plane.
When the wood is wider than the plane, the technique is modified as follows. Grip in the vice a similar piece of wood about 75mm (3in.) wide. Clean the dirt and roughness from one of the wide surfaces and draw on it three pencil lines (Fig 30). Proceed to plane as before, in groups of three shavings, either left side, right side and centre or left, centre, right. After three cuts, if all trace of the pencil mark is gone, the score is one. Continue in groups of three as before up to ten. Start again if a trace of pencil remains. It is not necessary to take off a line with each cut, but after three cuts all the lines must be gone. Repeat as before for a second group of ten.
If the wood is wider still a group of four, five or more cuts will be necessary. The important thing is that the planing must be regular and consistent. Planing haphazardly all over the board will never produce a flat surface.
Just as a building requires a true and accurate foundation from which all the subsequent measurements can be taken, so every piece of wood requires one accurate surface from which sizes and angles can be taken later on. This is known as the true face (often confusingly called the ‘face side’). There is a straightforward method of obtaining the true face, which can be tried out on a softwood piece of about 300 x 75 x 25mm (12 x 3 x 1in.).
Grip the wood in the vice and plane off the dirt and roughness from one large side (Fig 31). Resist the temptation to clean up all sides – it may look nice but there is a good chance of ending up under the required size. Now make a thick, soft pencil mark at each end (Fig 32). With a fine set plane try to plane the piece hollow. That is, start the cut just inside the first pencil mark and lift off just before the second. Continue this process with a fine set until the plane no longer cuts. Failure will be shown by the removal of a pencil mark. If this happens replace the mark and continue.
When the plane will cut no more, plane the wood from end to end. The first cut will remove a small shaving from each end, and subsequent shavings will get bigger. When a full-length shaving has been produced, stop, and test for accuracy (Fig 33). Naturally, if the workpiece is wider than the plane, groups of cuts will be taken in this way.
Tests for a true face
There are three tests for a true face:
1. Is the work flat in length? Test with a steel or wooden straightedge which must be longer than the work (Fig 34).
2. Is the work flat in width? Test in several places with a rule (Fig 35).
3. Is the work ‘in wind’ (i.e. twisted)? ‘Wind’ is pronounced as in ‘winding a clock’ or ‘on a winding road.’ Test with a pair of winding strips. Place a winding strip on at each end, step back a couple of paces then sight across the top of the winding strips. These magnify twist and quite a small error will be revealed (Fig 36).
Correct where necessary, then test again. Take care that in correcting for one of these tests, one or both of the others is not disturbed. When all the tests have been satisfactorily passed, put on a pencil face mark (Fig 37).
For some constructions the true face is inwards, others require it on the outside. It is important to bear this in mind when examining the timber before facing. In other words, does the best-looking surface have the true face or not?
The true edge (sometimes called the ‘face edge’) is the next important stage in producing material to size. The work already faced is held in the vice edge upwards and preferably with the true face outwards (Fig 38). This latter will of course depend on how the grain runs. The process is similar to that of facing. Clean the dirt and roughness from the edge on which the face mark stands. Make a strong pencil mark at each end (Fig 39). Plane as previously to hollow the workpiece between the marks, continuing until the plane no longer cuts. Now plane right through, stopping when the first full-length, full-width shaving results (Fig 40).
Tests for a true edge
1. Is the work flat in length? Test with a straightedge longer than the work (Fig 41).
2. Is the work flat in width? Test with a rule; if the last shaving was full width the work will be flat in width automatically (Fig 42).
3. Is the edge square (i.e. at 90°) to the true face? Test with a try-square in several places (Fig 43).
Correct where necessary and mark with a ‘vee’ pointing to the true face (Fig 44). Often a cross is used which is not so useful. If the face mark is lost the ‘vee’ indicates which side it was. If the edge mark is lost the face mark does the same.
When the test for squareness has been made (Fig 45), it is more than likely that one side of the wood will be higher than the other. The obvious remedy appears to be to tilt the plane. However, this will merely produce a second surface (Fig 46), making it even more difficult to settle the plane. It was stated earlier that the jack plane blade is sharpened to a curve and advantage will now be taken of this. With the plane correctly adjusted (Fig 47), a shaving cut in the centre of the plane will be of an equal thickness across its width. A shaving cut near the edge of the plane will have a thick side and a thin side, the latter thinning down to virtually nothing. Settle the plane on the workpiece (Fig 48). Successive shavings cut in this manner will gradually reduce the high side to squareness. The last shaving should be cut using the centre of the blade.
In order that the plane does not wander sideways during the stroke the normal grip is replaced by the edge grip. The left hand no longer holds the front knob but instead grips the sole just behind it with the thumb and first finger. The finger acts as a fence preventing sideways movement (see photographs 8 and 9). This is the standard method for planing all edges accurately.