|Wood Harvesting with Hand Tools - An Illustrated Training Manual (ILO, 1989, 128 p.)|
If saws become badly out of tooth line, it is necessary to adjust the tooth line. This can best be done by using a new saw which is properly shaped as a model. Its tooth line is marked with a scribe on the old saw (1). A second line is drawn underneath at the correct gullet depth. This can also be done after jointing with a scribe attached to the jointer (2). The position of tooth points is also marked on the old saw to avoid incorrect spacing.
If a new saw is not available, a thin flexible board (or a straight-back saw) can be used to draw the desired curve (3). It is fixed on both ends and bent in the middle to the correct tooth line shape. If a straight line (3a) is drawn between the two ends of the board, the correct curve is obtained if the middle of the board is bent outward (3b) by 7 cm for 1.5 m saw length, by 8 cm for 2.0 m saw length and 9 cm for 2.5 m saw length.
Reshaping the curve according to the new tooth line marked on the saw is facilitated if shears can be used instead of files. Shears may be found in central workshops.
Use of a press
In central workshops, it may also be useful to provide a press for deepening gullets and reshaping worn saws (4). This saves files and time.