12
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 1,5mm 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.
9.5
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 the 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. 12.0
,
Troubleshooting
.
9.6
Maximum performance tips
The versatility designed into the JWDS‐series drum
sander allows it to be used for a variety of tasks that
will boost return on your investment. For example, it
will speed up fine sanding work often done with
slower, dust‐generating hand sanders, and will
achieve fine thickness adjustments not possible on
some sanders. It can be used to surface figured
woods – bird’s eye or curly maple, for example –
which can be damaged if fed through a planer.
Learning how to use its adjustments and controls will
allow you to fine‐tune the machine for maximum
results. The best results come from experimenting
with
different
abrasive
grits
and
machine
adjustments to fit the job at hand. Following is a list
of useful tips which can help you improve
performance of your sander.
9.6.1 Dust collection
When connecting dust collectors, remember that
straight pipe will not restrict airflow as much as
flexible tubing. Y’s and elbows will restrict airflow less
than T’s. Also, a hose smaller than 80mm diameter
should not be used.
9.6.2 Multiple‐piece sanding runs
When abrasive planing (or thickness sanding) a run of
similar pieces that you want to have the same
thickness, it is best to determine the thickness of the
thinnest piece and process all pieces to that same
thickness in one session. Be aware that the sander
will remove cups and crowns in the workpiece;
consider this when measuring and processing stock
to the same thickness.
9.6.3 Simultaneous multiple pieces
When sanding multiple pieces simultaneously, make
sure to stagger (step) the pieces across the width of
the conveyor belt. This provides better contact with
