25
Reasons for wrong
measurements on an
M7 sawmill.
A. Incorrect adjustment
or set-up.
B. Cutting equipment
misfunction.
C. Tensions in the
wood.
A. Checking the M7
1. Check that all four legs
stand firmly and that the feet do
not sink into the ground when a
heavy log is loaded.
2. Sight over the log beds
and cross beam to check that
the sawmill stands straight.
Check both loaded and
unloaded.
3. Use a square to check
very carefully that the guide rail
is at an exact 90° angle to the
long legs. Even a small devia-
tion can lead to large
measurement errors.
4. Set the distance between
log bed and guide bar so that it
is exactly the same to both log
beds. Make sure the guide bar
and the log beds are fully
parallel. Use the setting block
included with the machine.
5. Check that the guide rail
is absolutely straight by sighting
along the guide rail or by running
a line over the guide rail and
using nails or something similar
as spacers between the line
and the guide rail.
6. Check that the guide bar
is straight in relation to the
sawing direction by placing a
1.5 m (5 ft) strip of wood on the
guide bar without the chain.
Sight across the strip to make
sure it is parallel to the guide
rail.
Even factory-new guide bar
mounts can be out of true. This
is discovered if the parallel
relation to the log bed changes
when the guide bar is turned. A
bent guide bar is most easily
straightened by being pressed
up or down while the saw is
mounted on the sawmill (see
page 21). An out of true mount
is corrected for by placing
washers between the carriage
plate and the slide rail.
7. The set-up of the M7 can
be checked by placing a board
with maximum length on the log
beds. First trim off a narrow
strip from one side of the board.
Then turn it, set both log beds to
the same height and remove a
similar strip. Now measure the
width of the board carefully. If
the board is not the same width
along its entire length it can
mean that the log beds are
incorrectly set or that the guide
rail is crooked. It is also possible
that the guide rail has been
depressed by the weight of the
log. When a heavy cutting unit is
used, this problem can even
occur if the support legs are not
on a rigid surface. If a chain-
saw is used the same thing can
happen if you extend the guide
rail more than 0.5 m (1.5 ft)
without adding support legs.
B. Checking the
cutting equipment
The guide bar must not cut
upwards or downwards during
sawing. This is most obvious
when the guide bar leaves the
log. If the guide bar does not
simply float out of the log but
springs up or down, problems
can arise. In such cases there
can be something wrong with
the guide bar or the chain.
Reasons for misfunction in the
cutting equipment:
1. One frequent reason for
problems when using the M7 is
that the chain is dull (see page
26).
2. The chain may be
damaged on one side, such as
by metal objects in the log. The
chain may still cut, but pulls up
or down (see page 27).
3. The chain may have been
filed wrong. The cutters may be
filed less on one side than on
the other. To get a more even
result, try to maintain the same
working position when filing the
left and the right sides of the
chain. That individual cutters are
faulty or that some are missing,
such as after sawing through
nails, usually has very small
effect on the function.
4. When precision
diminishes after a period of
fault-free sawing, it is almost
always due to wear on the guide
bar (see page 27).
Trouble-shooting
Continued on the page
following.
