Product Manual

14
Figure 9-3
9.5 Evaluating cutting efficiency
Is the blade cutting efficiently? The best way to
determine this is to observe the chips formed by the
cutting blade:
If chip formation is powdery, then feed rate is much
too light, or blade is dull.
If chips formed are curled, but colored — that is,
either blue or straw-colored from heat generated
during the cut — then feed rate is too high.
If chips are slightly curled and are not colored by
heat — blade is sufficiently sharp and is cutting at
its most efficient rate.
9.6 Blade selection
The saw is provided with a blade that is adequate
for a variety of cut-off jobs on a variety of common
materials.
See Table 3 for recommended speeds for various
materials. These selections, while appropriate for
many shop cutting needs, do not encompass the
wide variety of blades of special configuration (tooth
pitch and set) and special alloys for cutting unusual
or exotic materials.
A coarse blade could be used for a solid steel bar
but a finer tooth blade would be used on a thin-wall
tube. In general, the blade choice is determined by
the thickness of the material; the thinner the
material, the finer the tooth pitch.
A minimum of three teeth should be on the work
piece at all times for proper cutting. The blade and
workpiece can be damaged if the teeth are so far
apart that they straddle the workpiece.
For very high production on cutting of special
materials, or to work hard-to-cut materials such as
stainless steel, tool steel, or titanium, ask your
industrial distributor for more specific blade
recommendations. Also, the supplier who provides
the workpiece material should be prepared to
provide very specific instructions regarding the best
blade (and coolant or cutting fluid, if needed) for the
material and shape supplied.
Speed/FPM Material
100 Tool Steel, Stainless Steel,
Phosphor Bronze, Hard Bronze,
Hard Cast Iron, Malleable Iron
165 Mild Steel, Soft Cast Iron,
Med. Hard Brass,
Med.Hard Bronze
230 Soft Brasses and Bronzes,
Hard Aluminum, Plastics
Table 3
9.7 Blade break-in procedures
New blades are very sharp, and therefore have a
tooth geometry which is easily damaged if a careful
break-in procedure is not followed. Consult the
blade manufacturer’s literature for break-in of
specific blades on specific materials. However, the
following procedure will be adequate for break-in of
JET-supplied blades on lower alloy ferrous
materials.
1. Clamp a round section workpiece in the vise.
The workpiece should be 2 inches or larger in
diameter.
2. Set saw on low speed. Start cut with a very light
feed rate.
3. When saw has completed 1/3 of cut, increase
feed rate slightly and allow saw to complete the
cut.
4. Keep the same settings and begin a second cut
on the same or similar workpiece.
5. When blade has completed about 1/3 of cut,
increase feed rate. Watch chip formation until
cutting is at its most efficient rate (sect. 9.5) and
allow saw to complete the cut. The blade is now
considered ready for regular service.