CIRCULAR SAWS

There are several types of circular saws suitable for cutting Vical acrylic. Table saws vary in size from small, light­duty models to large, heavy production models, and are generally used for cutting Vical acrylic to close dimensions. The size table saw most commonly used is a medium duty model with an arbor of 3/4" to 1" diameter and powered by a 1 1/2 to 5 horsepower motor. Special jigs and fixtures are often used to hold the work steady for accurate cutting.

Radial saws and swing saws move while the work is held stationary and are generally used to make angle cuts and cross cuts in narrow pieces of Vical acrylic. Since the length of cut of a radial saw is limited to about 24", these saws are not used to cut large sheets.

Panel saws are of three types. The first has the saw blade and motor mounted above the material to be cut. The work is clamped to the saw table and the saw is fed through the work. The second type has the saw blade and motor mounted below the material to be cut. The blade extends above the table high enough to cut through the material. This type of panel saw is usually set so that the saw blade must be retracted before the saw guard and hold­down bar can be released. The third type of panel saw is mounted nearly vertically and offers advantages in that less floor space is needed; large sheets of Vical acrylic may be placed on the saw more easily; and there is less danger of scratching unmasked sheets of Vical acrylic.

Circular saws should be powered with motors rated at a minimum of 1 1/2 hp, and should run at speeds of 8,000 to 12,000 linear feet per minute (3­4,000 rpm for a 12" diam. blade). Saws should be equipped with heavy­duty, production type fences, and should be well guarded and have sawdust removal systems. Kick switches and brakes should be provided as safety features.

Saw blades should be equipped with carbide tipped, square and advance teeth. Square and advance teeth are designed so that alternate teeth start and finish the cut. Carbide tipped blades give cuts of superior quality, cut faster, and require fewer blade changes because of dulling. When the blade does become dull, however, it must be returned to the factory for resharpening.

To obtain the optimum cut from carbide tipped blades, the saw and stabilizer discs must fit the arbor closely with a clearance of about .001", and must run true. Loose bearings, bent arbors, or misaligned or burred stabilizers will vibrate and cause cuts of poor quality and shorten blade life. For maximum service life, carbide tipped blades used for cutting Vical acrylic should not be used to cut any other materials.

Where the quantity of the Vical acrylic acrylic sheet to be cut does not warrant the purchase of carbide tipped blades, steel blades designed to cut Vical acrylic may be used instead. These blades are made of alloy steel and are tempered to permit filing. The teeth should have a positive rake angle of zero to ten degrees and should be of uniform height and shape. When cutting .150"or thinner Vical acrylic, the blades should be hollow ground rather than set. Teeth of uneven height will cause chipping of the Vical acrylic and will place undue cutting strains on a few teeth. This may cause the saw blade to crack. The saw blades should be machine filed or ground

For cutting very small quantities of Vical acrylic, standard hollow ground fine­tooth blades used for cross cutting wood may be used. Table 1 lists recommended saw blade dimensions for cutting various thicknesses of Vical acrylic.