Figure. No. 1. Represents part of the frame of a com mon sash, showing a section through one of the sides, and a part of the plan of the sill.
No. 2 The side of the sash-frame, with the pulley style, and the sections through the sill and head.
No. 3. Part of the elevation of the sash-frame, the inside lining being removed to show the weight.
Figure 2. No. 1. A complete plan of a sash-frame, where the lines are concealed ; this, however, does not affect the plan, so as to make it differ from that of common sashes, as shown at Figure 1, No. 1.
No. 2. The pulley style, exhibiting the pulleys in the middle, instead of being much nearer the top than the middle.
No. 3. Part of the elevation, showing how the line is fixed to the lower sash, and hooked to a piece fixed to the trunk for the purpose.
No. 4.-Part of the elevation on the other side, showing the manner of fixing the line to the upper sash, and to the No. The inside of the sash-frame, with both weights exposed.
SAW, (from the Saxon saga, or Danish sawc) a thin plate of steel, indented on the edge, for cutting, or dividing wood or soft metals, by a reciprocal change of motion in the hands of the workman, by pushing it from, and drawing it towards hint. The cut which it makes, or the part taken away, in a board, is a thin slice, contained between parallel planes, or a deep narrow groove of equal thickness. Saws are several kinds, as the pit-saw, the bow-saw, the ripping-saw, the half ripper, the hand-saw, the panel-saw, the tenon-saw, the sash-saw, the dove-tailed saw, the eompass-saw, and the hey-hole or turning saw. The teeth of these saws are all formed so as to contain an angle of 60 degrees, both exter nally and internally, and incline more or less forward as the saw is made to cut transverse to, or in the direction of tho fibres ; they are also of different lengths and breadths, accord ing to their use. The teeth of a saw are bent alternately to each side, that the plate may clear the wood ; and, for this purpose, also, the edge on which the teeth are cut is thicker than the other edge.
The best saws are made of steel, ground bright and smooth. If in bending the plate of a saw, the resistance be great, and the curvature uniform, it is a proof that it has been evenly ground, and well hammered. Saws intended to cut hard wood, must be so sharpened as to lean more from the per pendicular drawn from the internal angle, to the line passing along the bottom of the teeth, than those which are intended for cutting soft wood.
The pit-saw is used by two sawyers, for dividing the trunks of trees into boards of any thickness, or for dividing The bow-saw is for cutting the thin edges of wood into curves.
The ripping-saw is used for dividing or slitting wood in the direction of the fibres ; the teeth are very large, there being eight in three inches, and the front of the teeth stand perpendicular to the line which ranges with the points; the length of the blade is about 2S inches.
The halfripper is also used for dividing wood in the direc tion of the fibres; the length of this plate is the same as the former, but there are only three teeth in the inch.
The hand-saw is used both for cutting the wood in the direction of the fibres, and for crosscutting; for this pur pose, the teeth are more reclined than those of the two former ; there are 15 teeth contained in 4 inches. The length of the plate is 26 inches.
The panel-saw is used for cutting very thin wood, either in a direction of, or transverse to, the fibres. The length of the plate is the same as that of the hand-saw, but there are only about six teeth in the inch. The plate of the hand-saw and panel-saw is thinner than that of the ripping-saw.
The tenon-saw is generally used for cutting wood trans versely to the fibres, as the shoulders of tenons. The plate of a tenon-saw is from 14 to 19 inches in length, and the number of teeth in an inch from 8 to 10. As this saw is not intended to cut through the wood in its whole breadth, and the plate would be too thin to make a straight kerf, with out being in danger of buckling, there is a thick piece of iron fixed upon the upper edge, called the back. The open ing through the handle, for the fingers, of this and the fore going saws, is closed all round ; and is therefore called a doable handle.
The sash-saw is used by sash-makers in forming the tenons of sashes : the plate is 11 inches in length. The inch con tains about I3 teeth ; this saw is sometimes backed with iron, but more frequently with brass.
The dove-tail saw is used in drawers. The length of the plate is about 9 inches, and the inch contains about 15 teeth. This plate is also backed with brass. The handles of the two last saws are only single.
The compass-saw is for cutting curves upon the surfaces of wood. For this purpose it is narrow, without a back, and thicker on the cutting-edge, as the teeth have no set. The plate is about an inch broad next to the handle, and dimi nishes to about a quarter of au inch at the other extremity ; there are about live teeth in the inch; the handle is single.
The key-hole or turning-saw is similar to the compass-saw in the plate, but the handle is long, and perforated from end to end, so that the plate may be inserted at any distance within the handle. The lower part of the handle is provided with a pad through which is inserted a screw, for the pur pose of fastening the plate in the handle ; this saw is used for turning out quick curves, as key-holes, &e. ; whence its name.