b - saw width s - thickness sl - value of the saw set on side t - blade/saw pitch h - height of the blade γ - tool rake angle (8-10 or 12-15) α - clearance angle r - gullet rounding radius
As a condition of correct sawing, the right saw has to be selected, depending on the type of machine and material to be sawn. Saws are available in sizes ranging from 0.8 mm to 1.45 thick. The saw thickness should correspond to the machine’s DTR, however, the thicker the saw, the more it is exposed to wear cracking. The saw width should match the width of guide pulleys plus the saw gullet depth (+1-3 mm). The pitch of a cutting saw is expressed as a distance between two neighbouring cutting edge tops. Selecting the proper pitch depends on both dimension and hardness of wood being sawn. The standard tooth is scaled at 22.2 mm. The tool rake angle is an angle included between the cutting edge’s surface and a line perpendicular to the saw back. In most cases of sawing the tool rake angle is between 10-12°. The tool rake angle recommended for hard and/or frozen wood is 8-10°, while for soft wood it is 10-15°. An excessive tool rake angle to a feed applied causes saw vibration, affecting the smoothness of the resulting surface. On the other hand, as the tool rake angle is insufficient, the saw end up being forced in the wood. The smaller the tool rake angle, the lower the cutting effectiveness.
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