Raising/Lowering Saw Head; Controlling The Cut: Hydraulic Feed Control; Evaluating Cutting Efficiency - Jet J-7020 Operating Instructions And Parts Manual

knob is turned counterclockwise.
decreases when the knob is turned clockwise.
2. A placard on the drive belt guard provides
recommended speeds for various materials.
3. A speed indicator is provided on the barrel of
the adjustment mechanism. The indicator
provides speed indications in feet per minute
and meters per minute. (The meters per
minute values are shown in parenthesis on the
indicator.)
4. The feed rates on the placard are expressed in
meters per minute. The feed rate graduations
available on the indicator may not match the
recommended feed rate. An approximate
speed may therefore
example, to set a speed rate of 25 meters per
minute, the indicator would be set about
midway between 21 meters-per-minute and
the 30 meters-per-minute graduations.
To change speed, the saw
motor must be operating.
5. Turn the speed adjustment knob to the desired
rate setting as determined by the material
being cut.
Figure 2: Coolant pump switch

8.3 Raising/lowering saw head

1. Lift the saw head using the handle on the far
left side of the saw head.
2. To lower the saw head, press the green
pushbutton on the right side of the control
panel.
3. To adjust the feed rate, adjust the feed rate
control valve knob on the top of the saw head
(see Figure 3).
4. To lower the saw head with power off, pull and
turn the red knob (manual override) on the
electro-magnetic valve (see Figure 4).
Speed
be required. For
9
8.4 Controlling the cut: Hydraulic
feed control
The weight of the saw arm provides all the force
needed to move the saw blade through the
workpiece. In fact, if the full weight of the arm is
allowed to make the cut, rapid blade wear and poor
cutting accuracy will result. A hydraulic feed control
is provided that gives the operator a means to
control the speed and efficiency of cutting.
The hydraulic cylinder is attached between the saw
base and the saw head. The hydraulic cylinder
resists movement of the saw head in the downward
direction. However, the hydraulic cylinder offers no
resistance when the saw head is raised upward.
The amount of downward force can be controlled
by using the feed rate control valve. When the
valve is opened slightly, the saw head will move
downward. The further the valve is opened, the
faster the saw head will move downward.
The feed control is adjusted by the operator until
the saw is operating efficiently. This is usually
determined by observing the chip formation. (See
section 8.5, Evaluating cutting efficiency, for more
information.)
Figure 3: Controls
Figure 4: Lowering head with power off

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.