Figure 12-9.14-inch band saw.
Avoid twisting the blade by trying to turn sharp
corners. Remember that you must saw around comers. If
you want to saw a very small radius, use a narrow blade.
If you find that a saw cut cannot be completed, it is
better to saw out through the waste material to the edge
of the stock than to back the blade out of the curved cut.
This will prevent accidentally drawing the blade off the
BAND SAW teeth are shaped like the teeth in a
hand ripsaw, which means that their fronts are filed at
90 degrees to the line of the saw. Reconditioning
procedures are the same as they are for a hand ripsaw,
except that very narrow band saws with very small teeth
must usually be set and sharpened by special machines.
A broken band saw blade must be BRAZED when
no accessory welder is available. The procedure for
brazing is as follows:
1. SCARF the two ends to be joined with a file so
that they may be joined in a SCARFJOINT(fig. 12-10).
2. Place the ends in a brazing clamp, or some
similar device, that will permit them to be brought
together in perfect alignments.
3. Coat the filed surfaces with soldering flux.
4. Cut a strip of silver solder the length of the scarf
and the width of the blade. Coat it with flux and insert it
between the filed surfaces.
5. Heat a pair of brazing tongs bright red and clamp
the joint together. The red-hot tongs wiIl heat the blade
and melt the solder. Keep the tongs clamped on the joint
until they turn black.
6. Smooth the joint on both sides with a flat file, and
finish it with fine emery cloth.
Figure 12-11 shows band ends being joined by using
the butt welder-grinder unit. The entire procedure for
joining is as follows:
1. Trim both ends of the band square; clean them
thoroughly. Butt the ends together in the jaws of the
welder-grinder unit; make sure that the ends are aligned
and that the seam is centered between the welder jaws.
First, set the resistance knob to agree with the dial for
the width of band you are going to weld Then press and
Figure 12-10.Rejoining a broken band saw blade.