880 thf farmers' handbook. 



The operation is, needless to say, a delicate one and three things are 

 essential in handling the file : — 



1 . The top side of the file itself must be held at exactly the same angle 



on every tooth. By merely altering the angle at which the 

 triangular file is leaning a very uneven job will result. If, for 

 instance, the top side of the tile leans first at the angle shown in 

 Fig. 19 and then at another angle, it is impossible for the job to be 

 a satisfactory one. It is this angle that determines the amount of 

 "hook " on each tooth, and it is most important that it be uniform. 

 The angle indicated in Fig. 19 (the top side of the file not quite 

 flat, but leaning slightly to the tip of the saw) will give a satis- 

 factory " hook." This hook should be greater in the case of the rip- 

 saw than in other types. 



2. The hand must be held at a uniform height throughout ; it should not 



be held first high and then low, or an uneven set of teeth must 

 result. Some men drop the hand and file upwards, but this is not 

 satisfactory. The file should cross the saw at right angles to the 

 side of the saw — in other words the point of the file should neither 

 he elevated nor depressed, and it should be so throughout the job. 



3. The direction at which the tile is worked across the saw, must also be 



uniform. Swinging the hand from one side to the other will be as 

 unsatisfactory as swinging up and down. In the case of a rip-saw, the 

 file must go straight to and fro at right angles to the length of the 

 saw. With other saws, the handle of the file should be slightly 

 inclined towards the tip of the saw. The effect is to form a sort 

 of diamond point. 



If the teeth are in good order and regular it is only necessary in sharpen- 

 ing to see that the tile is pressed firmly into the angle between the teeth, 

 but if the teeth are uneven the file must be used with a little weight on 

 it, one way or the other, to put the teeth in order again. Where a saw is in 

 very bad order indeed, it is sometimes necessary to run the teeth down and 

 retooth the saw, cutting out new teeth. 



The alternate teeth having been treated in the way described, the remain- 

 ing teeth are treated in the same way and with the same care from the other 

 side. 



Setting the Saw. 



The " set " of the saw is a term employed to suggest the amount of spread 

 that the teeth have sideways, the teeth being pointed alternately one way 

 and then the other. Only one-third of the tooth should be bent outwards — 

 the whole of the tooth should not have an outward lean. 



With the rip-saw, very little spread is needed — sometimes none at all, but 

 with the hand-saw (used for cutting across the grain) there should be more 

 set, especially for green timber. When the teeth are set, there should be a 

 distinct V or slight depression down the centre if the saw is held so that you 

 look along the tips. The teeth must be evenly set, one side having no more 

 spread than the other. A special "saw-set" can be obtained, which can be 

 simply adjusted to the size of tooth and amount of spread desired (Fig. 20). 



