Band saw

For years the problem which confronted saw makers was how to reduce the time and power consumed, as well as the waste in sawdust, in converting logs into boards. Eventually the perfection of the band saw proved to be the solution.

The Saw. William Newberry of London, England, patented the first endless band saw in 1808, although his machine was never developed further than the model submitted to the Patent Office. The great difficulty in making a smooth, strong joint in the steel band was a stumbling-block which arrested practical development until New berry's time.

The old difficulty in joining the blade so it would run over the wheels without breaking was not overcome until nearly forty years after Newberry gave this type of saw to the world.

The Steel. When one considers that the modern band saw travels at the speed of about one and one-half miles per minute or faster than the fastest express train that in connection with its width it is extraordinarily thin, one will have some idea of the strain to which it is subjected, and a better conception of the wonderful quality of the steel that has made the production of these saws possible.

The band saw which remains today in practically the same form as when invented is still the last word in saw efficiency. It is in the perfection of a suitable steel to withstand the successive bending and straightening while in operation, the making of a proper joint or "braze," and the improvement in the form of the teeth that modern advances have been made.

Widths. Wide band saws which today range in size up to 18 inches in width, are familiar to almost everyone. They consist of an endless band, or ribbon of steel, usually toothed on one side. They are also made with both edges toothed. This is usually done in the case of large band saws, although double-edge band saws are sometimes made in width as narrow as 8 inches.

The early log machines used quite narrow saws, 3 inches to 5 inches wide, but owing to the fact that by using wider saws a faster rate of cutting could be obtained, and that there are a number of experienced men who understand their treatment, a very much wider saw than was formerly the case, has come into use.

The Wheel. The band saw is run over two wheels, or pulleys, which, in the case of perpendicular band saw machines, are set one above the other, and spaced some distance apart.

Thin Blades. The band saw has superseded the circular saw in several lines of work. It has many advantages over the circular saw especially in that class of sawing where its very thin blade makes it desirable. Band saws from 2 to 8 inches in width, are extensively used for ripping and resawing, for, compared with the circular saw, they save kerf, time, and power.

This leads us to the consideration of the band saw as related to the sawmill. Before its introduction there was a limit in size of timber which could be sawn by circular saws, which could cut only logs of a size slightly less than half the diameter of the saw. The size of the saw itself was also limited; difficulties of management and running arose as soon as the saw diameter was increased beyond a certain point.

Double Mills. Double mills were used to a great extent in regions where large timber was being cut. By this arrangement, which consisted of two circular saws, one above the other, logs of an ordinary size were sawn
with the larger or main circular saw, while the smaller, or "Top Saw," was brought into action when a log exceeded the capacity of the main saw. The band saw obviated all this, for there is practically no limit to the size of logs which can be cut by band saws.

In large band mills, as a rule, the work is brought to the saw upon a carriage driven by feeding devices independent of the saw.

Continuous Cutting. Compared with the reciprocating saws formerly used in sawmills, such as mill, gang, etc., the band saw has the advantage of steady and continuous cutting action, no time being lost in return stroke.
However, gangs of reciprocating saws, by reason of their ability to cut as many as 30 boards at one time, are still retained in numbers of large mills as an adjunct to the bands.

When one considers the value of every 1/16 inch saved in kerf in the course of a day's sawing of several hundred thousand feet, the great economy in using the thin blade band saw can be more fully appreciated.

Large Bands. Large band saws for log sawing range from 8 to 18 inches in width. The general width for single-edged bands, i.e., toothed on one edge, is 12 inches, while double-edged band saws are made in a variety of sizes. The majority of these latter, however, are about 14 inches in width, although, as previously stated, some few are made as narrow as 8 inches.

The length of the standard log band saw varies, according to size and make of mill, from 40 to 60 feet.

Double-edged band saws are now used frequently and the log can be cut as it moves in both directions.

The swage set is principally used on log bands and resaws. Swaging the teeth consists of spreading or widening the cutting edge of each tooth so that it extends slightly beyond each side of the blade, giving clearance to the body of the saw while cutting. Sufficient clearance prevents friction and insures free running.

Then, too, with the swage tooth both corners of the tooth cut, consequently it will not only do twice as much work as a spring-set tooth, which merely cuts half a kerf, but in addition it will stand more feed, thus greatly increasing the capacity of the mill.

The band resaw which is now extensively used has been successfully operated in gangs. There are mills in the United States and Canada using gangs containing two or more machines.

The Hand. The experienced sawyer or mill man is familiar with the "hand" of a band saw, but for the benefit of the beginner it may be stated that a saw is either right or left hand. As you stand facing the mill with the teeth of the saw toward you, if the log passes on the right hand side, it is a right hand saw; if it passes on the left of the saw it is a left hand saw.