30 BULLETIN 718, TJ. S. DEPARTMENT OF AGRICULTURE. 
guides the saw in a measure, and should be filed square across. If 
a saw is frozen, always thaw it out before attempting to set the 
teeth. 
The greatest wear on the saw is on the under edges of the teeth. 
File nearly to an edge, but not quite, leaving a short bevel of one- 
thirty-second of an inch wide on the underside of the point. But 
in no instance file to a fine point or thin wire edge. Do nearly all the 
filing on the underside of the teeth and see that they are well spread 
(swedged) at the points. File square across and have them pro- 
ject alike on both sides of the saw. 
On crosscut saws, bevel the front of one tooth one way and the next 
tooth the opposite way. File rip saws square in front; use a light 
hammer in swedging, from three- fourths to 1 pound, holding the 
swedge so that the teeth will spread at the points. Swedge out wide 
and then dress down to the required width. Most cases of saws 
" crumbling " are caused by the use of too delicate a swedge. In 
such cases the corners of the tooth are not strong enough to stand 
the cutting strain. 
Be sure to have a side file for jointing the teeth and keeping all 
the points the same length on each side of the saw. 
The cost of changing solid-tooth saws into inserted-tooth saws is 
usually $1.50 per tooth plus one-half the list price of a solid-tooth 
saw of the same size. 
Inserted teeth. — It is not economical to spend much time filing in- 
serted teeth, because new points are cheap and are quickly inserted. 
It should never be necessary to swedge the bits. Light filing on the 
underside is the only thing required to keep them sharp, because the 
cutting point tapers gradually and allows plenty of clearance, even 
though the point is worn almost entirely away. Swedging is likely 
to injure the shoulders and sockets, unless great care is taken in the 
operation. Use a light 1-pound hammer and hold the swedge so that 
the teeth will be spread at the point. Have a cup of oil, together 
with the teeth, placed conveniently near you at the- back of the saw. 
Take the wrench and plaice the pins in the holes in the shank, turning 
the latter so that the hook projects sufficiently to receive the bit. 
Pick up a tooth with the other hand and dip the grooved segment 
into the oil, then place it in position and hold it firmly and evenly 
with the sides of the blade, and at the same time press the wrench 
downward until the shank fits into its place. The inserted teeth 
are exact in width and the spread uniformly good. If extra nice 
work is desired, try a gauge on the side of each tooth. If any are 
found to project a trifle too far, reduce them with a side file, being 
careful to preserve the same relief of the corner. No flat surface 
should be allowed on the side of the teeth, which must be relieved 
from the very point. 
