The Technique of FURNITURE MAKING

SAWS AND SAWING

A standard kit for hand work would auto­matically include rip-, crosscut - and panel - (small crosscut-) saws, tenon - and dovetail- saws, with bow-, scroll - andpad-saws, etc. for circular cutting. Where machinery is available

the rip and big crosscut might not appear necessary, but there will always be the occasion when it is easier to take the saw to the wood rather than the wood to the machine; therefore to some extent they are indispensable. While the rip-saw (46:1) has upright teeth (46:2) filed square to the blade (46:3)—the arrows give the filing direction—and cuts with a chisel action (46:4), all other saws are of the crosscut type (46:5) for cutting across the grain, the teeth are raked (46:6) and with the exception of the fine dovetail-saw are filed to a bevel of about 65° (46:7) so that the set of the teeth scores two parallel lines across the wood and the waste or 'kerf between crumbles away in dust (46:8). The "set' or alternative bending outwards of each tooth which practically every saw must have if it is to clear itself must never be more than is required to give fractional clearance to the blade as it passes through the wood, while in the case of the larger saws (rip-, large crosscut - and panel-saw) the blade itself should have the full thickness along the teeth but the back
should be taper ground, i. e. 'swaged', about four gauges thinner from handle to point for heavy saws, and correspondingly less for lighter saws. The blade also should be tensioned by hammering the centre of the blade to expand it, and the test of a handsaw of good-quality tempered steel and correctly tensioned by the maker is that it should neither sag nor exhibit any tendency to floppiness when held by the handle in a horizontal position. The teeth also should be of even height and shape, filed to the correct bevel, with each individual tooth set to about half its depth only, so that the kerf made in the wood is never more than about 11/2times the thickness of the blade.

A convenient size for rip - and big crosscut - saws for cabinet-work is 26 in (660 mm) long not including handle, with 41/2 points (teeth) to the inch (25 mm) for the former and 7 or 8 points for the latter. The smaller crosscut - or panel-saw, one of the most useful of saws if in good condition, should be about 22 in (558 mm) long with 10 points to the inch (25 mm). Tenon-saws (47:1) and dovetail-saws (47:2), which are not taper ground, have their blades stiffened with a rib or back of steel or brass (apart from appearance it hardly matters which), and convenient sizes would be 12 in (304 mm) long with 12 to 14 points for the tenon, and 8 in (203 mm) long with 18 to 22 points (the finer the better) for the dovetail. Both these saws have a more pronounced rake to their teeth (47:4), but the dovetail teeth are so fine it is difficult to file a correct bevel, and the teeth are usually left square across their faces as in the rip. An open or pistol-grip handle is preferable for the dove­tail if it can be obtained (47:2) but most manufacturers seem to regard it as just another tenon-saw, which of course it is and is not. It cuts so finely there is always the temptation to use it indiscriminately, but it should be kept exclusively for dovetails and fine mitres. An even finer saw is the bead-saw, sometimes known as the 'joiner's fancy' or 'gent's' saw. with bradawl-type handle (47:3), a blade from 4 in (101 mm) to 8 in (203 mm) long and with 32 points to the inch (25 mm). As it is a little difficult to file the teeth evenly it is sometimes discarded when too blunt to cut, for it is relatively inexpensive.

47 Handsaws: tenon and dovetail Sharpening saws

Skilled craftsmen sharpen their own saws, using a pistol-grip saw set to bend the points, and a suitable threee-cornered tapered saw-file which is gripped with both hands. For the rip-saw the file is held level as a chisel edge is necessary to the points; but for crosscut-saws the near or back hand should bear slightly downwards to form a point to the teeth. In all cases alternate teeth are filed from one side, the saw reversed and the remaining teeth filed, making sure that the 'gullet" or space between each tooth is kept constant and only sufficient metal is taken off to destroy the 'shine' which is the evidence of a blunt tooth. If the worker does not feel confident of setting and filing his saws correctly—and fair practice is needed—then they should be sent to a "saw-doctor'.