Jet JWBS-15 Operating Instructions And Parts Manual

Contents

Jet JWBS-15 Operating Instructions And Parts Manual Manual pdf 23 page image

23Figure 9-39.4 ResawingResawing is the process of slicing stock to reduceits thickness, or to produce boards that are thinnerthan the original workpiece. Figure 9-4demonstrates resawing.The ideal blade for resawing is the widest one themachine can handle, as the wider the blade thebetter it can hold a straight line.When resawing thin stock, use a push block, pushstick, or similar device to keep your hands awayfrom the blade.Figure 9-49.5 Blade leadBlade lead, or drift, is when the blade begins towander off the cutting line even when the band sawfence is being used. Figure 9-5 shows an exampleof blade lead. It is more common with small, narrowblades, and is almost always attributable to poorblade quality, or lack of proper adjustments. Inspectthe band saw for the following:• Fence not parallel to miter slot and blade.• Blade not tensioned correctly.• Blade is dull.• Teeth have excessive “set” on one side ofblade.• Workpiece being fed too quickly.Figure 9-59.6 Saw blade selectionUsing the proper blade for the job will increase theoperating efficiency of your band saw, help reducenecessary saw maintenance, and improve yourproductivity. Thus, it is important to follow certainguidelines when selecting a saw blade.Here are factors to consider when selecting a blade: The type of material you will be cutting. The thickness of the workpiece or part. The features of the workpiece or part, suchas bends or curves with small radii.These factors are important because they involvebasic concepts of saw blade design. There are five(5) blade features that are normally changed to meetcertain kinds of sawing requirements. They are:1. width2. pitch (number of teeth per inch)3. tooth form (or shape)4. the "set" of the teeth5. the blade material itself.9.7 WidthBand saw blades come in different standard widths,measured from the back of the blade to the tip of thetooth. Generally, wider blades are used for rippingor making straight cuts; narrower blades are oftenused when the part being cut has curves with smallradii. When cutting straight lines with a narrowblade, the blade may have a tendency to wander,causing blade lead. (refer to sect. 9.5).9.8 PitchPitch is measured in "teeth per inch" (TPI). Figure 9-6 shows blades with different pitches. A fine pitch(more teeth per inch) will cut more slowly butsmoother. A coarse pitch (fewer teeth per inch) willcut rougher but faster. As a rule of thumb, the thickerthe workpiece, the coarser will be the blade pitch. Ifyou have to cut a hard or very brittle material, youwill probably want to use a blade with a finer pitch inorder to get good clean cuts.