Set
The term "set" refers to the way in which the saw teeth are bent or positioned. Set patterns are usually selected depending on the type of material that needs to be cut. Three common set patterns are shown in Figure 36.
Generally, the Raker set is used for cutting metal workpieces; the Wave set, when the thickness of the workpiece changes, such as cutting hollow tubing or structurals. The Straight set is most often preferred when cutting wood or plastics.
2.Feeding work too fast
3.Using a wide blade to cut a short radius curve
4.Excessive tension
5.Teeth are dull or improperly set
6.Upper guides are set too high off the workpiece
7.Faulty weld on blade
Figure 36
Material
Band saw blades can be made from different types of materials. Some of the most common include spring steel, carbon steel, carbon steel equipped with a high speed or welded edge (bi- metal), or carbide tips. A special type of saw blade is made from "high speed steel"; these should not be used on band saws with low rates of speed.
Because of the importance of blade selection, it is recommended that you use the blade selection guide on page 25.
When cutting, do not overfeed the blade; overfeeding will reduce blade life, and may cause the blade to break.
Blade Breakage
Band saw blades are subject to high stresses and breakage may sometimes be unavoidable. However, many factors can be controlled to help prevent most blade breakage. Here are some common causes for breakage:
1. Misalignment of the blade guides
Maintenance
Before any intervention on the machine, disconnect it from the electrical supply by pulling out the plug. Failure to comply may cause serious injury.
Keep bearing guides clean and free of
Check that the cleaning brush over the band wheel is working properly, and remove any deposits from the band wheels to avoid vibration and blade breakage.
The table surface should be kept clean and free of rust for best results. Some users prefer a paste wax coating. Another option is talcum powder applied with a blackboard eraser rubbed in vigorously once a week; this will fill casting pores and form a moisture barrier. This method provides a table top that is slick and allows rust rings to be easily wiped from the surface. Important also is the fact that talcum powder will not stain wood or mar finishes as wax pickup does.
Do not let saw dust build up in the upper and lower wheel housings. Vacuum out frequently.
Connect the band saw to a JET dust collection system.
Clean and grease the raising/lowering rack for the upper bearing guides if it becomes difficult to raise or lower.
Clean and oil the tensioning mechanism if it becomes difficult to adjust.
Vacuum out the motor fan cover.
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