Three kinds of saws are in common use in cutting logs into lumber: circular, band and gang. Circular saws cut faster than band-saws but are rather wasteful because they cut such a wide kerf. A large circular saw frequently cuts a kerf one-quarter of an inch wide. Gang saws cut out several boards at the same time. Band-saws, because of their economy, are displacing the others.
The common forms into which logs are sawed are timbers, planks and boards. Timbers refer to the larger pieces such as are used for framing; planks are wide pieces over one and one-half inches thick; and boards are wide pieces less than one and one-half inches thick.
At the mill the log is drawn from the water, up a slide, [Fig. 213], by an endless chain. In the mill it is inspected for stones and spikes and then measured. Next it is automatically pushed out of the slip upon a sloping platform called the log deck where it is held by a stop until it is wanted at the saw.
Fig. 211.
THE GLENS FALLS BOOM, HUDSON RIVER, NEW YORK.
Fig. 212.
LOG POND NEAR OCILLA, GEORGIA.
Fig. 214.
DOUBLE CUT SAW MILL, PINOGRANDE, CALIFORNIA.
When the carriage is empty the stop is withdrawn and at the same time revolves so as to throw the log upon the carriage. Iron hooks called dogs are then fastened in the log in such a way that it cannot turn. [Fig. 214]. The carriage and log move toward the saw and a slab is cut off the log. A reversing lever takes the carriage back; again the log is moved to the saw. This is repeated until a few boards are cut off. The more modern band saws have teeth on each edge of the blade so that the log is cut as the carriage moves backward as well as when it moves forward.