26
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 39.
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.
Figure 39
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 27.
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
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
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 build-up.
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.