Bow-saw.

a stretcher, bb side-arms, c blade.

d tightener, e string. f end of blade with attachment.

g handle. 1/12.

The side-arms are connected at the other end by several strands of strong string, which are twisted together by a tightener, in order to give the required tension to the blade. When the string is put on, the frame is fastened between the bench pegs.

The stretcher is made of fir or pine; the side-arms of harder wood, e.g., beech or oak. The different parts of the frame are made as light as is compatible with strength, that the saw may not be too heavy to manage with one hand.

In working, the saw should be firmly grasped by the side-arm just above the handle. In the case of the lighter description of saws, the handle, as well as the lower part of the side-arm, should be held in the hand, and the index finger should steady the blade.

Manner of holding the saw.

Fig. 39. Saw blade end, with attachment. 1/4.

Fig. 39. Saw-blade end, with attachment. 1/4.

Generally speaking, the blade is fixed obliquely to the plane of the frame; partly that the worker may saw deeply without hindrance from the frame, and partly that he may be able to see the line which the saw is to follow.

In tightening the blade - which is best done by turning both handles simultaneously - care must be taken that it is perfectly straight. Otherwise a straight cut can hardly be obtained.

Tightening the blade.

If the saw is out of use for any length of time, the tightener should always be slackened. When this is not done the side-arms may become twisted.

Bow-saws have different names, depending on the nature of the blade. The "hook," i.e., angle of the teeth is shown in Fig. 32.

A. The Broad-webbed Bow-saw is shown in Fig. 38. Its blade is 1 to 1 1/2 inches broad. It is used in numerous cases, e.g., in sawing off long slips of wood, where a straight cut is all that is required. It has 4 to 5 teeth per inch.

B. The Turn-saw (Fig. 40). The frame resembles the preceding, but the blade is very narrow - about 1/4 inch, or very little more - because it is used to produce curvilinear cuts. The toothing is very fine- 7 teeth per inch - and the setting is sometimes less than in the bow-saw, that the cut may be accurate, and not unnecessarily broad.

Turn-saws, the blades of which are over half an inch in breadth, are also used. These are called broad-webbed turn saws.

2. Saws without Frames.

1. The Hand-saw (Fig. 41) has a very broad blade, which is narrower at one end, and is provided at the broader end with a convenient handle. The large blade gives it sufficient strength, and this is often increased by the thickness of the blade, which may exceed that of the frame-saw. The teeth are set to cut when the worker pushes the saw away from him, but not when the saw is drawn back.

This saw, distinguished for its simplicity and convenience in working, is in general use in England and North America, but is not much used in Sweden.

I Saws 42

Pig. 40. Turn-saw. 1/12

Fig. 41. Hand saw. 1/8.

Fig. 41. Hand-saw. 1/8.

2. The Dovetail saw (Fig. 42) has a very broad blade of equal breadth throughout, with a handle. To give sufficient strength to the blade, its upper edge is enclosed in an iron back. This thick back limits the depth of the cut; consequently this saw is only used for shallow incisions, e.g., in sawing out tenons, dovetails, etc. This saw has 10 to 12 teeth per inch. The shape of the teeth is shown in Fig. 32, but they are often sharpened with advantage in the manner shown in Fig. 33.

[3. The Tenon-saw is practically the same as the dovetail-saw, but it is rather larger, and it has what is called a Box-handle, somewhat like that of the hand-saw. - Trs.]

4. The Compass-saw (Fig. 43). The blade is very narrow, and terminates in a point. This saw is used when an excision has to be made in the centre of a piece of work, and cannot be begun from the edge. For this purpose a hole must be bored, into which the point of the saw can be inserted. To give the blade sufficient strength it is made tolerably thick, but it becomes thinner towards the back. Compass-saws are of various sizes, and the teeth are set in different ways. The number of teeth varies from 5 to 12 per inch, but their form is in most cases that shown in Fig. 32.

4. The Groove-saw * (Fig. 44) has a tolerably thick blade of equal breadth throughout, the upper edge of which is entirely enclosed by a handle, which is worked by both hands. The teeth are inclined towards the worker, and consequently act when he draws the saw towards him.

Fig. 42. Dovetail saw. 1/6.

Fig. 42. Dovetail-saw. 1/6.

Fig. 43. Compass saw. 1/6.

Fig. 43. Compass-saw. 1/6.

* Unknown in England, but recommended as useful. - Trs.

It sometimes happens, especially in clamping and grooving, that an incision must be made in a broad flat piece of wood, and in many cases it must not be carried to the edge. With the exception of the tenon-saw, the saws hitherto described cannot be used for this purpose. The groove-saw is perfectly adapted for it, whereas the tenon-saw is not quite so convenient, because the setting of its teeth is not suitable, and it has only one handle.