MAINTAINING A RAKER-TOOTH CROSS-CUT SAW
Maintenance work follows the same pattern as for peg-tooth saws
except that, additionally, raker adjustment is needed. The saw is held at all
times in a vertical position during maintenance work.
Jointing is done in exactly the same way as for peg-tooth
Raker adjustment. The raker adjuster, correctly set, is
placed over a raker (2). Holding the tool firmly against the saw,
the raker is filed flush with the tool guide plate (2a). The raker
depth should be 0.2-0.5 mm for hard wood and 0.6-1.0 mm for soft wood
(2b). The correct depth must be found under working conditions and
will be indicated by properly-shaped saw chips.
Raker filing is done after adjusting the raker height
(3). It is continued until the flat is as small as possible.
Horizontal file strokes are used (3a). The raker angle should be
90°. It can be checked easily during filing with the top end of the
mill-saw file (3b).
Cutter teeth filing is done with the saw in the oblique
position (4). A top angle of 70 and a side angle of 35 must be produced.
Filing strokes should not exceed 60 per minute. The full length of the file is
used and an even pressure put on the file. Check the angles with the gauge
frequently and when the flat almost disappears, tap the top of the tooth with
the file handle or small piece of wood. This gives a true picture of how much
flat is left. The last strokes with the file must be very gentle. Sharpening
is finished when the flat is just about to disappear.
Deburring. Put the saw in a vertical position. The fine
side of the whetstone is run along both sides of the saw to remove burrs
(1). Be careful not to touch the sharp teeth with the fingers.
Setting (2). Check that the saw is held
very firmly in the vice. For a right-handed man, the left arm is put over the
saw, taking care not to catch the saw with the arm or body, and the anvil held
in the left hand. Those teeth with the bevels towards the body are set first.
The anvil is placed against the back of the cutter. The cutter is set with short
and firm strokes of the setting hammer held in the right hand (2a, 2b).
The setting indicator is used to check the set of each tooth
(3). The correct saw set for hard wood is 0.1-0.2 mm, for soft
wood 0.2-0.4 mm (4). Insufficient set is corrected at once by
further hammer strokes. If the set is too great it is removed with the setting
hammer after the position of the anvil has been changed (5). After
setting one side, the saw is turned round and the other side is set.
Note: The first six teeth on either end of the saw need
Setting normally follows cutter teeth filing but the order can
also be reversed.
Deepening of gullets. At intervals of about four weeks,
it is necessary to deepen the gullets on the cutters (6a) and the gullets
between the rakers (6b) with the millsaw file and the big gullets between
the rakers and the cutters (6c) with the round file.