Select the right tooth form for clean cuts and efficient chip removal. Blade geometry
Pitch Pitch refers to the number of teeth per inch. Pitch selec- tion should be based on the thickness of the material to be cut. Thin materials require a greater number of teeth-per- inch, or a finer blade. Thick materials require fewer teeth- per-inch, or a coarser blade. Other factors, such as work- piece material and finish must be considered for final pitch selection, but at least two teeth should be in contact with the workpiece at all times. Not all blades have a con- stant number of teeth per inch. These variations are described below. Decimal Pitch Decimal Pitch blades are a DoALL exclusive, designed to reduce sawing noise and vibration to lengthen blade life and reduce operator fatigue. When the right Decimal Pitch blade is selected for a job, it will also cut faster and cleaner than other types of blades. Teeth are arranged on a Decimal Pitch blade in a har- monically derived ratio to tune out vibrations. A blade with a 5.5:9 blade for example, begins with a relatively coarse 5.5 pitch, gradually increases to the equivalent of a 9 tooth-per-inch pitch, then gradually decreases to a 5.5 pit- ch. See illustration below. Single Pitch (conventional) Blades Conventional blades have a consistent number of teeth per inch throughout the entire length of the band. These blades are best suited for cutting solids of consistent density, where vibration and noise are less likely to be a problem.
A number of physical features of a blade determine its suitability for various types of work. Some of these charac- teristics are described briefly below, as an aid to the pro- per selection of the blades that will offer the best combi- nation of accuracy, productivity and blade life.These char- acteristics include: Blade width Blade width is measured from the back of the blade to the tip of the tooth. The wider the blade, the greater its beam strength. Wider blades follow layout lines with greater ac- curacy. For straight cuts, use the widest blade your machine will hold. For contour cuts, use the widest blade that will cut the smallest radii required by the work. See the chart below.
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