This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
The first thing to be considered is the position of the stuff while being operated upon. Board or plank should be laid on one or more saw-horses a in either a sloping or flat position, the saw being held more or less nearly vertical, while the workman rests his right knee firmly on the work to secure it. If the stuff is more than 3 in. thick it should be lined on both sides, and repeatedly turned so that the sawing proceeds from opposite sides alternately; this helps to ensure straight and regular cutting. The saw is held firmly in the right hand with the forefinger extended against the right side of the handle. The workman's eyes should look down on both sides of the saw. As the work progresses, a wooden wedge should be driven into the slit or "saw kerf" b, to allow a free passage for the saw. Care is needed not to draw the tool too far out of the cut, or the end will be " crippled " by sticking it into the wood when returning it to the p cut. Grease should be applied freely to lubricate the teeth. Sometimes the saw-horse is dispensed with and the work is laid on the bench and held down by the hand or by mechanical contrivances, either with the end of the stuff hanging over the end of the bench, or with the edge hanging over the side.
The operator can then stand erect at his work and can use one or both hands. Continental workmen often use the rip-saw with the back of the saw towards them; they place the work on saw-horses and commence in the usual way, then turn round and sit on the work and drive the saw before them, using both hands.
For cutting wide tenons, the stuff is first gauged with a mortice gauge (p. 186), and then secured in a bench vice in a more or less vertical position. The saw is first applied in an almost horizontal position, the workman taking care to adhere to the line so that the tenon may have the proper size when done. As soon as the saw has entered the line it is inclined in such a way as to cut down to the bottom of the mark on the side farthest from the operator. When that has been reached, the stuff is reversed, and the saw is worked in an inclined position till the opposite shoulder has been reached. This gives the limit of the cut at each edge, leaving a triangular piece uncut in the middle of the slit, which is finally removed by setting the work and using the saw in an exactly horizontal position. This facilitates working with truth and accuracy to the square. Large work is best done with a rip-saw; small, with a hand- or panel-saw. The left hand seizes the wood to steady the work and the workman. The workman makes a cut with the grain of the wood, which should always be the first half to be performed.
When the longitudinal cuts have been made, the cross-cuts or shoulders are made by laying the wood flat on the bench against a stop.
For cross-cutting timber, the hand-saw is commonly used; the teeth are finer than in the rip-saw, and are set a little more to give greater clearance in the kerf, as the tool is more liable to gain when cutting across the fibres of the wood. The saw is held in the right hand, the left hand and left knee being placed on the work to steady it on the saw-horses. The workman must proceed very cautiously towards the end of the cut, and provide some support (generally his left hand) for the piece which is about to bo detached, or it will finally break off and perhaps produce long splinters that will render the work useless for its intended purpose. When cross-cutting on the bench, the work rests firmly and flat on the bench, the end to be removed hanging over the side so that it can be held by the left hand. Unless the piece is very heavy, some means must be provided for holding it still during the sawing, or a slight movement may twist and damage the saw.
For sawing work that is slightly curved, a narrow rip-saw must be used, and the kerf must be kept well open by inserting a wedge. In ripping planks or tenons, both hands may be used to advantage in guiding the saw. In all tawing, the tool should be grasped in the right hand, while the left may rest on the material, or may be used to assist in working the saw. In the first few strokes, the length and vigour of the stroke of the saw should be gradually increased, until the blade has made a cut of 2-4 in. in depth, after which the entire force of the arm is employed : the saw is used from point to heel, and in extreme cases the whole force of both arms is used to urge it forward. In most instances, little or no pressure is directed downwards, or on the teeth; when excessive effort is thus applied, the saw sticks so forcibly into the wood that it refuses to yield to the thrust otherwise than by assuming a curved form, which is apt permanently to distort it. The fingers should never extend beyond the handle, or they may be pinched between it and the work. To acquire a habit of sawing well, the work should, as often as practicable, be placed either exactly horizontal or vertical; the positions of the tool and the movements of the person will then be constant.
The top of saw-benches should be level. The edge of the saw should be exactly perpendicular, when seen edgeways, and nearly so when seen sideways; the eye must narrowly watch the path of the saw, to check its first disposition to depart from the line set out for it: look only so far on the right and left of the blade alternately as to bo just able to see the line. To correct a small deviation at the commencement, twist the blade as far as the saw kerf will allow; the back being somewhat thinner than the edge, the true line may be thus returned to. Make it a habit to watch the blade so closely as scarcely to require any correction. The saw, if most "set" (having the teeth standing higher) on one side, cuts more freely on that side, and has a tendency to run towards it.
The " table " or " ship-carpenters' " saw has a long narrow blade intended for cutting sweeps of long radius; it is handled similarly to the rip-saw. The "compass" saw with its long (12 in.) and narrow (tapering from 1/8 in. to 1 1/4 in.) blade generally resembles the hand-saw; in use it is apt to buckle and snap in short curves, unless it is filed so as to cut by a pulling motion instead of with a thrust.. The "pad" or "socket" saw is a more diminutive form of the preceding, made to slide into a hollow handle, where it is held by screws, only so much of the blade being drawn out as is required; it should be filed for the pulling stroke. The " web " or " bow " saw is a narrow ribbon-saw fastened in a frame; it has very line teeth, adapted for cutting both with and across the grain; the chief use is for fretwork, the blades being made to twist round to suit the work. "Back" saws are of several kinds, all characterised by deep thin blades: the "dovetail" is the thinnest, and simple filing usually gives it sufficient set; great care is necessary with it to prevent buckling and kinking, a twist of the hand sufficing to ruin it. " Tenon " and " sash " saws being somewhat thicker require a little set.
All back-saws need to be kept well oiled and polished, and are best used in a mitre-box (p. 187) or other guide rest; they should be held firmly when in use, but with the least possible force exerted in controlling their direction; the cut should be commenced by placing the heel (handle end of the blade) of the saw on the farthest edge of the work and drawing it towards the body of the operator (Hodgson).
This tool, it must be remembered, in forming its saw kerf, removes, in the shape of sawdust, a solid bit of the material, which is thereby channelled as much as if the kerf had been formed by a very narrow iron fitted in a grooving plane. This is practically ignored by many amateurs, who carefully saw to line, and remove that line in doing so, and then find that the piece is cut too small. Of course, the wider the saw is set, the broader is the piece removed. A great many apparently unaccountable misfits are due to this error, which accounts also for the absence of squareness in framed work - for all the marked lines are seldom thus effaced. Casting the eye along a saw of which the teeth are turned upwards, this tool will be seen to contain an angular groove caused by the alternate bending outwards of its teeth. These, if properly filed, present also, taken together, 2 knife-like edges d e (Fig. 303), which are very keen, and form the outside limits of the saw kerf: one of these edges, therefore, right or left, as the case may be, must just touch the ruled line upon the work, but must not encroach upon it. The result will be a clean true cut if the saw be in good order; but one tooth having too much set (projecting beyond the general line) will spoil it.
Thus, in Fig. 303, b c are the limits of the intended kerf, of which the darker line b is the guide line to be left on the work; but the tooth which stands out too far reaches to the line a and quite effaces b.