Set; Material; Blade Breakage - Powermatic PM1800B Operating Instructions And Parts Manual

Figure 52 – Blade Set

14.4 Set

The term "set" refers to the way in which the saw
teeth are bent or positioned. Bending the teeth
creates a kerf that is wider than the back of the
blade. This helps the operator more easily pivot a
workpiece through curve cuts, and decreases
friction between blade and workpiece on straight
cuts.
Set patterns are usually selected depending upon
the type of material that needs to be cut. Three
common set patterns are shown in Figure 52.
Generally, the Raker set is used for cutting metal
workpieces; the Wavy set, when the thickness of the
workpiece changes, such as cutting hollow tubing or
structurals. The Straight, or Alternate, set is the one
most used for woodworking blades, and is also used
to cut plastics.

14.5 Material

Band saw blades can be made from different types
of metals. The most common include spring steel,
carbon steel, bimetal (alloy steel equipped with a
high speed cobalt steel edge welded to it), or
carbide tips.
Because of the importance of blade selection, it is
recommended that you use the blade selection
guide, sect. 14.0. Also, listening to experienced
band saw users will produce valuable information as
to the types of blades currently on the market along
with their pros and cons.

14.6 Blade Breakage

Band saw blades are subject to high stresses and
breakage may
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 workpiece too quickly.
3. Using a wide blade to cut a tight 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.
Although not essential, some users round or "stone"
the back edge of their blade. This is done by placing
a sharpening stone on the table and in light contact
with the back corners of the blade as the blade is
running. Rounding can help the back blade edge
move more smoothly through the kerf, smooths the
weld, and helps prevent cracks from starting at the
back corners.
29
sometimes be unavoidable.