430 THE YOUNG FARMER'S MANUAL. 



bearings will not be true with the collars. If the lathe be rather 

 light, and it springs when the collars are being turned, the man 

 drel should be put in the lathe, and the face of the fixed collar 

 turned while the mandrel revolves on its own bearingsfamd not 

 merely on the centres of the lathe. Sometimes the collars must 

 be turned a little concave, to fit the saw well, and sometimes one 

 must be a little concave and the other one correspondingly con 

 vex or straight, as the shape of the saw requires. The mandrel 

 should fit snugly the eye of the saw without any play. When 

 the saw is placed on the mandrel, if it deviates any in revolving, 

 it may be adjusted by a piece or two of paper, between the col 

 lar and the saw, and be made to run with the greatest precision. 

 The bearings should be so neatly fitted to the boxes, that there 

 will be no working of it up and down, nor any play endways. 

 (See FITTING UP MACHINERY, in the next volume.) In sawing 

 anything where exactness is not necessary, if there should be a 

 little play of the mandrel endways, it matters not ; but in sawing 

 to a gauge, if there be much play of the mandrel endways, some 

 pieces will be thicker or longer than others, according to the 

 amount of play. 



BALANCING SAWS. 



658. When saws are hung on a mandrel having a fly-wheel 

 on it, if it is not well balanced the saw will vibrate or flutter at 

 the edge, and the frame will shake like a person who has been 

 attacked with the quotidian ague. When a saw is well balanced 

 the frame will not tremble, even when the motion is very high. 

 (See How TO BALANCE A SAW, in next vol.) 



GUMMING SAWS 



659. Is the act of making the teeth longer by making the 

 spaces between them deeper. This is performed in several ways. 

 The best mode, but most expensive, is, to gum with a file; be 

 cause by gumming with a file there is no danger of breaking or 

 bending a saw, nor of stretching the edge. And if the spaces 



