The log is hauled up to the

bull chain and automatically stops at the loading point. When a log is kicked off the chain a new log is hauled up in position

The sawing of logs is done by two men-one head sawyer and one helper. These men need not possess great skill, because all logs of the same diameter are sawed in the same manner, according to schedules prepared at the mill office, and the sawyer's work is reduced to feeding the logs into the machine and to seeing that the machines are working properly.

When the log in position on the deck is to be transferred to the carriage, the head sawyer, standing in front of the machine and behind the carriage, pulls the lever and the low rolls onto the carriage. There are several types of carriages. The one used in Olympia has two sections one cradle in front consisting of a V-shaped steel beam mounted on two pairs of track wheels running on ball bearings. This carriage is provided with an automatic device by which it returns to its position after the log has passed on to the saw. The rear carriage is provided with a power-driven device for feeding logs into the machine. It has a V-shaped steel beam in front and in the rear a pair of clamps which can be turned, opened, and closed by levers and handwheels. The clamps hold the log firmly in place. When the carriage reaches a certain point, a tripping device releases the log and the carriage returns automatically to its position. (See fig. 5.) In this manner the loading of logs onto the carriages and the feeding of logs to the machine are both accomplished by one man, without exertion, and at a very rapid rate.

As soon as the log has left the front carriage and is passing through the machine the head sawyer transfers another log to the carriage, and the sawing of the second log closely follows the first. There is, therefore, no lost time, and one log after another is cut in a continuous stream.

The helper standing at the rear of the machine operates a carriage similar in construction to the claw carriage in front, but the object of this carriage is merely to keep the sawed boards together. When the log has passed through the machine, the butt end of the log falls onto a supporting carriage, and the helper pulls a lever, driving the carriages with the sawed lumber to a point where it is to be unloaded. (See fig. 6.) At this point the claws on the carriage automatically releases, leaving the lumber to rest on the carriage beams. The helper now steps on a treadle, and the carriage beams are tilted at a steep angle, causing the timber to slide onto the transfer to the edger. From that point and on the edging, trimming, and grading of lumber is exactly the same as in most American plants, and the machinery for these processes is of American make.

SCANDINAVIAN GANG SAWS

The Scandinavian types of gangs are different from other original designs, although recently attempts have been made by manufacturers in other European countries to copy them. They differ from other types in that they have been built for high speed and also in the automatic features of their auxiliary machinery.

One must not confuse the Scandinavian gang saws with the American type, because American gang saws are designed for cutting heavy cants. They are therefore of heavier construction, use two or three times as much power, and are not designed for cutting round

logs, which is a special feature of the Scandinavian saws. There is as much difference between the Scandinavian saw and the American saw as there is between a race horse and a draft horse. The former is built for speed and light work; the latter is a heavy-duty machine.

While the American gang saws are of the oscillating design, the Scandinavian type has the saws hung at an angle, cutting on the down stroke, leaving a clearance for the saws on the up stroke. This, in connection with other features of the Scandinavian machines, gives them very smooth operation, which again is reflected in smooth cut of the lumber.

Both upper and lower feed rollers are power driven, and the upper roller follows the contour of the log like a caterpillar, thus making it, possible for the machine to negotiate even very rough logs. Both rollers swing out separately, which helps in making adjustments and in changing saws. Saws may be changed in from 10 to 15 minutes. The sash consists of steel girders connected with seamless steel tubes. The crank bearing is equipped with self-aligning roller bearing. The feed is continuous, and the friction disk has its working side faced downward, whereby the friction roller is guarded against sawdust and oil. While the machine is running, the feed speed can be changed by operating a hand lever and can be reversed by stepping on a treadle.

The gang saws at the Olympia plant have a width of sash of 26 inches. Other types made have 22, 30, and 34 inches width. The stroke is 20 inches, and the machine operates at 325 to 350 revolutions per minute. The diameter of the driving pulley is 391⁄2 inches and its face 812.

On account of the difference in the class of timber, Douglas fir being harder than European pine, the horsepower requirements are somewhat larger than those in similar European plants. The Olympia mill is using a 200-horsepower motor for the two gangs, log hauls, carriages, and unloaders. For one gang alone 75 horsepower would be sufficient. The size of the main frame is 5 feet 6 inches by 4 feet 6 inches. The weight of the machine is about 21,000 pounds.

It is of the greatest importance to secure a solid foundation for these gang saws, because failure at this point affects the accuracy of the cutting through excess vibration of the machine. (See figs. 7 and 8.)

SAWS

Scandinavian spring-set saws of 15 Birmingham wire gage were furnished with the machines. These saws had been designed for the use of European softwoods and were not suitable for the cutting of Douglas fir, which is of considerably harder texture. Later on swaged saws 14 Birmingham wire gage of both American and Swedish manufacture were substituted. This question of saws is not yet solved, and in cooperation with the committee, American saw producers are experimenting with both swaged and spring-set saws. Several different designs of saw teeth are now being tried out, and a special grade of steel is being produced in order to permit the use of thin saws. The question of whether spring-set or swaged

cawe are better for the nurnose of producing accurately manufac

logs, which is a special feature of the Scandinavian cowg There is

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