26 BULLETIN 718, U. S. DEPARTMENT OF AGRICULTURE. 
In ordering a circular saw be careful to give the following speci- 
fications in detail : 
1. Diameter of the saw in inches. 
2. Right or left hand mill. 
3. Gauge of saw at center and at rim. 
4. Number of teeth in saw. 
5. Style or pattern of tooth, solid or inserted. 
6. Diameter of mandrel hole, diameter of pinhole and distance, center to 
center of pinholes. 
7. Number of revolutions of saw per minute, while in cut. 
8. Greatest feed in inches per revolution and kind of feed. 
9. Species of timber to be sawed. 
10. Spring or swage set. 
11. Horsepower available and size of belt pulley. 
12. Engine speed and size of mandrel pulley. 
SIZE. 
The size of the saw should be governed by the size of the logs to 
be cut, regardless of the amount of power used. The diameter of the 
saw should be approximately one and a half times the diameter of 
the largest log to be cut. For instance, a 36-inch log needs a 54-inch 
saw, a 40-inch log a 60-inch saw. The width of the widest board 
which a single circular saw can cut equals the radius of the saw 
minus 3 inches; that is, a 60-inch circular saw can cut a board or 
plank 27 inches wide. 
HANGING A SAW. 
Set the saw plumb and true. Set the saw guide and adjust the 
guide pins clear of the teeth and. just touching the plate. This 
should be done while the saw is in motion, care being taken that the 
pins do not push the saw to one side or rub hard enough to cause 
friction. After screwing the saw up between the collars examine 
the front or log side of the saw to make sure that it is flat. Xever 
attempt to run a saw that is dishing on the log side, as it will be 
sure to draw toward the log and be ruined. It does not follow that 
because one saw works well that another will do so on the same 
mandrel, or that two saws will hang alike on the same mandrel. 
It is absolutely necessary that the saw mandrel should be perfectly 
level, so that the saw will hang exactly plumb. If it is found to be 
rounding on the, log side, cut a ring of paper about half an inch 
wide the size of the collar on the outside, oil it, and stick it on the 
face of the tight collar around the outer cage. Then cut another 
ring of paper the same width, making the hole the same size as the 
hole in the saw, put this small ring between the loose collar and the 
saw, and screw up the collar. If the two rings are not enough, put 
in more until the saw stands straight and true. If the saw hangs 
dishing on the log side, reverse the rings of paper; that is, put the 
