FDM - April 2008

FDM
THE WOOD
DOCTOR’S R_x

fdmonline.com

Gene Wengert

wooddoc@uwalumni.com

Steamers, sanding
and pinkish maple

➤ a head that bends slightly, especially

in the center, when cutting heavy loads (high stock removal, using the machine like a planer instead of a sander);

➤ a head that is out of balance so when operating at full speed it bends;

➤ a worn head so that it is no longer

uniform in size and shape;

➤ bearing run-out;

➤ improperly aligned hold down

mechanism;

➤ worn bed plate (with a single-head

sander especially) which often results because the full width of the sander was not used, but pieces were predominately sent through the center of the machine;

➤ inadequate dust removal system

so that dust accumulates on the lumber and prevents smooth surfac-

ing; and

➤ worn or loaded belts,

especially a problem

if the pieces are sent
You need to recalibrate ^through ^the ^center ^ofthe machine most of
and change a few ^the ^time.Perhaps the first
_internal _settings.step is for you to _measure _the _thick-ness of your sanded
stock every half inch
across the width. Take
these measurements near
both the entering and the
tailing end of the piece. Measure
ten pieces or so. Plot the results. Next,
change the sanding belts; then, set
the machine to the same settings as
before, run some pieces through and
then repeat the measurements.

Q:We have a wide-belt sander, but the thickness of the sanded stock varies within a piece. Also, the thickness readout does not agree with the actual thickness. I am new to this machine and so could use some suggestions about troubleshooting.

●
Several wood
species are very
color-sensitive to
the application of
any chemical on
their surface.
●

A:It is not uncommon to find that the readout that the machine provides for thickness is not accurate. One reason is that different belts have different thicknesses, so each setting must accommodate the belt thickness. Even devices with belt thicknesses stored in memory are often incorrect. Further, it is possible, especially in older machines, that the device was not properly calibrated in the first place.

So, you need to recalibrate and maybe change a few internal settings. I do see a lot of people who use the present settings and then have a small correction chart alongside the machine, rather than spending time recalibrating.

Regarding thickness variation, there are several machine factors which can cause this. (I am assuming that the machine did run perfectly when it was first delivered, so we do not have a design or construction problem.) They include: