434 THE YOUNG FARMER'S MANUAL. 



teeth at c should be filed so that the cutting points shall be one- 

 sixteenth or one-twentieth of an inch more promin^Bhan they 

 are back of the points. (See Fig. 183, c.) If the material to be 

 sawed be such that each tooth is required to cut one-sixteenth of 

 an inch, by filing the ends of the teeth so that a line dr^^Krom 

 the point of one tooth would strike one-sixteenth of an inch below 

 the point of the first tooth back of it, the saw cannot draw into 

 the log any farther than it will cut without trembling, even if the 

 teeth be filed very hooked. 



669. At d is a form for teeth having a heel or guide to prevent 

 the saw from drawing into the log when sawing. The guides or 

 heels are dressed in a line with each other, at a given distance 

 back of the cutting edge. If, in sawing, the saw is inclined to 

 haul into the log, the heels prevent its entering any farther than 

 is desirable. 



670. At e teeth are represented with the points hammered; 

 i. e., with repeated blows on the back of a tooth, near the point, 

 with a light hammer, the edge is turned downward. There is a 

 saving of nearly one-half the power by hammering the teeth, if 

 it be performed very skillfully. If this spur should not all be 

 worn off before filing again, it is necessary to hold a smooth and 

 square piece of steel against the face of the tooth, and with a few 

 blows of a hammer upwards, bring this spur on a line with the 

 face of the tooth, so that it will not be filed off in dressing the 

 tooth. 



671. As hammering teeth, either for the purpose of setting 

 them or turning down the points, refines the steel and renders it 

 harder, the cutting quality of an inferior .saw is often improved 

 by working the points with a hammer when cold. 



672. It is of primary importance that a saw which works up 

 and down, should be jointed straight on the edge. If a saw is 

 allowed to become hollowing on the cutting edge more than one- 

 fourth of an inch, if everything is not made doubly strong, we 

 may surely expect that the saw or something else will break. If 

 the cutting edge is crowning from end to end, a saw cannot be 

 made to work up to its greatest capacity. A jointer for a mill 



