Jet Tools J-7040 - Manual (Page 10)

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8.5 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 the chip formation is powdery, then the feed rate
is much too light, or the blade is dull.
If the chips formed are curled, but colored — that
is, either blue or straw-colored from heat generated
during the cut — then the feed rate is too high.
If the chips are slightly curled and are not colored
by heat — the blade is sufficiently sharp and is
cutting at its most efficient rate.
8.6 Blade selection
The cut-off saw is provided with a saw blade that is
adequate for a variety of cut-off jobs on a variety of
common materials. A 4/6 vari tooth bi-metal blade
(5674011) and a 6/10 vari tooth bi-metal blade
(5674021) are available from JET.
See sect. 8.2, Setting blade speed, for the
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 cut hard-to-cut materials such as
stainless steel, tool steel, or titanium, you can
ask your industrial distributor for more specific
blade recommendations. Also, the supplier who
provides the workpiece material should be
prepared to provide you with very specific
instructions regarding the best blade (and
coolant or cutting fluid, if needed) for the
material and shape supplied.
8.7 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 the saw on low speed. Start the cut with a
very light feed rate.
3. When the saw has completed 1/3 of the cut,
increase the feed rate slightly and allow the
saw to complete the cut.
4. Keep the same hydraulic cylinder setting and
begin a second cut on the same or similar
workpiece.
5. When the blade has completed about 1/3 of
the cut, increase the feed rate. Watch the chip
formation until cutting is at its most efficient
rate and allow the saw to complete the cut
(see sect. 8.5, Evaluating blade efficiency).
The blade is now considered ready for regular
service.
9.0 Work setup
9.1 Securing workpiece for square
cuts
1. Raise the saw head (refer to Figure 5).
2. Slide the left vise jaw far enough to the left to
allow the workpiece to be placed in the vise.
3. Place the workpiece on the work table. If the
workpiece is long, provide support at the other
end. It may also be necessary to provide
additional downward clamping to hold the
workpiece securely on the work table.
4. Turn clamping hand wheel clockwise to clamp
the workpiece in position against the fixed
(right) vise jaw.
5. After completing the cut, turn the clamping
hand wheel counterclockwise and slide the left
jaw away from the workpiece.
Figure 5: Securing workpiece
9.2 Adjusting vise for angle cuts
1. Referring to Figure 6, loosen the angle locking
screw and the pivot screw on the left vise jaw.
2. Turn the locking handle on the round, angle-
setting block counterclockwise to unlock the