13
8.2
Switch safety key
To prevent unauthorized use of sander, turn off main
switch and pull out safety key (Figure 8-1). Store key
in a safe place. Key must be reinserted to start
sander.
Figure 8-1: control panel
8.3
Circuit breaker reset
If the sander becomes overloaded, the built-in
breaker will trip to help protect the motor. Allow the
machine to cool down, then push the reset button
(Figure 8-1) to restart.
If overloading happens frequently, refer to
Troubleshooting,
sect. 11.0.
8.4
Setting depth of cut
Adjusting the drum sander for proper contact
between abrasive and stock determines the depth
of cut. The depth of cut is controlled by the height
adjustment handle.
It may take experimentation to determine proper
depth of cut, given the variables of abrasive grit,
type of wood, and feed rate. For best results, use
scrap wood to practice sanding and to develop skill
and familiarity with the machine before doing finish
work.
A combination of several variables will determine
proper depth of cut to use, including the following:
1. Abrasive type and grit size.
2. Width of piece being processed.
3. Hardness of piece.
4. Feed rate of conveyor belt.
NOTE:
The use of a carrier or backer board (not
provided), is recommended for cuts 1/16” or less.
This is a flat board, usually of wood or MDF, slightly
larger than the workpiece and of even thickness,
placed beneath the workpiece as it is fed through
the sander. The workpiece may be attached to the
carrier with rubber cement, carpenter’s tape or
some other easily removable adhesive. Some
operators use a rubber or textured surface on the
carrier to help stabilize the workpiece by simple
friction.
8.5
Establishing drum height
A good rule of thumb when sanding with grits finer
than 80:
1. To establish drum height, position stock under
the drum. Do NOT start drum.
2. Lower drum to the stock thickness, making sure
drum can still be rotated by hand while just
contacting stock.
Do not start drum while in
contact with stock.
3. Without changing drum height, turn on
conveyor and run the stock out from under the
drum. Start sanding drum and sand stock at that
same position.
4. With the drum operating, feed stock under the
drum from the infeed side and against the
rotation of the drum. Always maintain control of
the stock to avoid kickback and/or slippage.
NOTE: If motor heats up during operation,
depth of cut may be too great for size of grit
and/or feed rate may be too fast.
For sanding with grits coarser than 80, you can
lower the drum slightly.
Always maintain control of stock. Through practice
you will learn the proper depth of cut considering the
variables above.
A faster feed rate allows faster sanding but fewer
revolutions of the drum per inch of sanding. A slower
feed rate provides more revolutions of the drum per
inch of sanding to allow a greater depth of cut and
smooth sanding.
Begin experimenting with the feed rate set at about
40% to 50% of maximum. The best feed rate will
depend on a number of factors, including type of
stock, grit and depth of cut used, and whether the
stock is fed directly in line with the conveyor table or
at an angle. If the drum motor is lugging down, if
conveyor belt is slipping, or if you observe a ripple
effect on the stock, slow the feed rate. If the finish is
smooth and the machine is not overworking, you
can experiment using a faster feed rate.
Also try a faster feed rate or less depth of cut if the
stock you are working begins to show burn marks.
With cherry, hard maple or other hardwoods, using
a shallower depth of cut and a faster feed rate will
help minimize burn marks. Slightly angling the stock
as it is fed into the machine will also help prevent
burning the stock.
Because of the wide range of variables, it is
important to experiment with your specific
conditions and make adjustments to achieve the
optimum feed rate. If problems occur, first check and
adjust the feed rate, referring to
sect. 11.0
,
Troubleshooting
.