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TESTS OF SCANDINAVIAN GANG SAWS ON PACIFIC COAST

PRESENT SAWMILL MACHINERY UNSUITABLE FOR CONVERTING SMALL TIMBER

American sawmill machinery is unsurpassed for the purpose for which it was designed-namely, to convert logs of large dimensions into lumber. Our sawmill-machinery engineers have concentrated their efforts in this direction, because heretofore little thought has been given to the raw material represented by top logs and small timber. The lumber industry realizes that its future depends on the growing of new timber crops; but commercial reforestation is predicated upon a closer utilization of the raw material than is practiced at present. Therefore, it is obvious that our present type of heavy sawmill machinery must be changed to meet these new conditions.

The United States Forest Service has conducted a thorough investigation of the cost of converting small logs into lumber in various parts of the country. Local conditions vary both as to stumpage values, transportation cost, and labor charges. For this reason it is impossible to establish a general rule governing minimum top diameter at which logs may be converted into lumber at a profit.

In some sections of the country operators are leaving in the woods only logs of smaller top diameter than 13 or 14 inches, while on the Pacific coast logs of less than 19 to 20 inches top diameter are not generally taken to the sawmills. There are, of course, exceptions to this rule, particularly in cases where logging operations are conducted close to the sawmills.

Cutting systems also vary throughout the country. In some instances the clean cutting of timber land is practiced. In other cases the stands are thinned by removing trees which crowd. Every tree felled has a top log, and the lowering of the top diameter of saw logs means a closer utilization of timber felled under any cutting system. It must be pointed out, however, that the indiscriminate felling of small trees regardless of good forestry practices will result in losses to the owner because these small trees form a nucleus for the second cut. Such practice is not advocated in this report.

If there are no facilities for profitable conversion of these small logs produced in accordance with good forestry practice, an important incentive for commercial reforestation is removed. It is well known, also, that leaving top logs and small timber on the ground. constitutes a serious fire hazard. If it were possible to utilize small timber of this character, 15 to 25 per cent greater utilization would result in many instances.

MISMANUFACTURE CAUSES HEAVY LOSSES

Not much progress has been made in the utilization of saw logs in most lumber mills during the last 25 years. There are hundreds of mills still using circular saws of heavy gauge, wasting 25 to 30 per cent of lumber in the form of sawdust. For each three or four boards cut one board is converted into sawdust.

Band saws have unquestionable advantages for sawing certain types of logs, but sawing practices vary to a great extent, and in many mills the lumber produced by them is not smooth. There are other mills, however, which pay especial attention to this point, keeping the saws properly filed at all times, and reducing speed in order to improve the manufacture of the lumber. As miscuts frequently occur, it is often necessary to "size" the stock in order to prepare lumber for the market. That is to say, one side and one edge must be dressed to insure uniformity of dimensions and smooth surface. This operation represents a waste of material as well as a waste of labor. On an average from 75 cents to $1.50 per thousand feet may be estimated as the labor cost of it. All in all, it is not safe to figure on more than a 50 per cent utilization of the logs cut on band or circular saws, and in many instances the percentage is less than that.

SCANDINAVIAN GANG SAWS INVESTIGATED BY DEPARTMENT OF

COMMERCE

In 1916 the Department of Commerce decided to investigate lumber manufacturing conditions in Northern Europe, and Axel H. Oxholm, now director of the National Committee on Wood Utilization, and then United States trade commissioner, spent two years among the sawmills in Norway and Sweden to study this question. In his reports-Special Agents Series 195, Swedish Forests, Lumber Industry, and Lumber Export Trade, 1921, and Special Agents Series 211, Forest Resources, Lumber Industry, and Lumber Export Trade of Norway, 1922-Mr. Oxholm pointed out the great advantage of the Scandinavian gang saws in converting small timber, and emphasized the fact that a utilization of these logs amounting to 65 or 75 per cent resulted from the use of Scandinavian gang saws. A noticeable fact is that the average top diameter of Scandinavian logs is only 62 to 7 inches, and that labor costs are even higher than those prevailing in certain sawmilling districts of the United States From these reports it also appeared that Scandinavian gang-sawed lumber is so smoothly and accurately cut that not a single plant was found where it was necessary to size the lumber in order to insure uniformity of dimension.

NATIONAL COMMITTEE ON WOOD UTILIZATION ESTABLISHES GANG-SAWING PROJECT

When the National Committee on Wood Utilization was estab lished in 1925, one of the first projects on its program was a thorough study of the application of Scandinavian gang saws to American conditions. A subcommittee of practical lumbermen was appointed to do this work, and following a preliminary study of two smaller

installations of Scandinavian gang saws in Virginia and New Hampshire the committee's director left for Norway and Sweden for the purpose of negotiating with the principal producers of Scandinavian gang saws for cooperation with the committee in making practical service tests in America. Such arrangements were concluded with Svenska Maskinverken, of Stockholm, Sweden, representing a merger of several Swedish and Norwegian gang-saw producers, and also with the J. & C. G. Bolinders Mekaniska Verkstads A. B., of Stockholm, on the basis that the Scandinavian companies would install their gang saws at any mill designated by the committee, and with no expense or other obligation except that the committee would undertake to test the machinery and issue a report.

The first installation was made at the mills of the Tumwater Lumber Mills Co. (Inc.), at Olympia, Wash., by Svenska Maskinverken, and a new mill was designed especially for this purpose by one of their engineers. (See frontispiece.) The installation was completed in April, 1929, Roy F. Morse, general manager of the LongBell Lumber Co., Longview, Wash., and a member of the committee, offered to conduct the tests for the committee, and for this purpose he and his engineers made several visits to the plant. The committee's director also visited the Olympia mill at the end of June and investigated the actual uses of this gang-sawed lumber in California. Arrangements have been made recently by the Scandinavian producers of this machinery for its manufacture by an American company, the Mill Engineering & Supply Co., of Seattle, Wash., through which concern the installation at Olympia was effected.

OPERATION OF OLYMPIA MILL

The Olympia mill differs from a typical Scandinavian mill in that it has been designed for the use of both Scandinavian and American machinery. Furthermore, the cost of logs in its relation to the cost of labor is smaller than in Scandinavia. For this reason it is not practical at present to carry out the Scandinavian sawmilling system to its full extent. There the utmost attention is paid to careful manufacture; speed is also an important element, but their timber is cut from reforested areas, and consequently there is a greater urge to utilize it to the best advantage. Quality of manufacture, therefore, is given first consideration, and speed is second. There is a noticeable trend in this direction in American plants, also, at the present time.

SORTING OF LOGS IN POND

The Scandinavian system of gang-sawing lumber is based on the careful sorting of logs in the pond according to top diameters. Thus, in some cases Scandinavian logs are sorted in multiples of a half inch and even a quarter inch in top diameter in order to take full advantage of the possibilities of utilizing the logs. For each log diameter class a special sawing plan is established, and the saws are set in the saw-guide frame according to this schedule.

At the Olympia plant this scheme has not been fully carried out, and the logs are sorted in four diameter classes only, as follows:

76975°-29-2

8 inches and less, 8 to 14, 14 to 18, and 18 inches and over. (See fig. 1.)

Inasmuch as this classification of logs is of great importance in increasing the overrun, the probability is that logs will be sorted in multiples of 1 or 11⁄2 inch in the future. The logs are stored in pockets in the pond. Four men are employed in the boom, who drive the logs toward the bull chain with the small end toward the saw. (See fig. 2.)

The majority of the logs cut at the Olympia mill are secondgrowth Douglas fir timber produced around Puget Sound. They are of No. 3 grade, and their principal defects consist of the tight knots which are characteristic of second-growth timber. (See fig. 3.) The percentage of clear lumber which might be produced by band-sawing these logs is small, averaging from about 3 to 6 per cent. The current lengths of the saw logs vary from 12 to 24 feet, but longer lengths may be handled. It is not considered practicable to cut logs shorter than 7 or 8 feet, as the carriages are not designed for them.

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FIGURE 1.-Log storage pond, Tumwater Lumber Mills Co. (Inc.), Olympia, Wash., showing pockets where logs of each top diameter class are stored

LOGS NOT STORED ON MILL DECK

The log deck differs from the American type, in that it does not provide for log storage space. This is due to the installation of a special log jack with automatic belt shifter. The log jack is installed to the right of the gang saw and at the end of the slip. At the end of the chain there is a lever, and when the log strikes this lever the belt is shifted on to the loose pulley and the chain stops. The moment the log is transferred to the carriage the chain automatically starts again and the next log is hauled up into place. (See fig. 4.) This is a very practical device and saves the service of one man who would otherwise be required to attend to the logs on the deck.

SAVING OF LOGS

There are two gang saws installed in this mill, one placed ahead and to the right of the other, and each having an independent log haul. This arrangement has been made with the idea of enabling the mill to use either of two Scandinavian sawing systems, which will be described later.

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FIGURE 2.-Log haul-up, Tumwater Lumber Mills Co. (Inc.), Olympia, Wash. A separate bull chain feeds the logs to each gang saw

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