The Crosscut Saw
The two-person crosscut saw was evidently known by the Romans though little used by them. It wasn't until the middle of the 15th century that the crosscut saw came into fairly common use in Europe. Records exist of the crosscut being used for cutting logs in the United States between 1635 and 1681. About 1880, Pennsylvania lumbermen began felling trees with the crosscut. Before that time, all trees had been ax-felled and crosscut into lengths.
Until the 15th century, the two-person crosscut saw used a plain tooth pattern. The M tooth pattern seems to have been developed and used in south Germany in the 1400s. Even as late as 1900 most of the European crosscuts still used the plain tooth pattern with a few exceptions of M tooth being used. Not until fairly recently was the saw with a raker or "drag" developed.
In the case of plain, M, and Great American tooth patterns, each tooth both cuts the wood and clears out the shavings. However, in the case of the champion, lance, and perforated-lance tooth, cutter teeth cut the wood fibers and the rakers remove the scored wood from the cut.
By the time crosscut use was at its peak, a large number of tooth patterns had been developed, each presumably suited to a particular set of conditions.
Tooth Patterns
Saws can be divided into two types: two person and one person. Generally speaking, a one-person saw is shorter, but its defining characteristic is that it is asymmetric. Both one and two-person crosscut saws can be used by either one or two persons.
At one time, one-person crosscut saws were made in lengths from 3 to 6 feet. Two-person saws were made in lengths from 4 to 12 feet for the Pacific Northwest, and up to 16 feet for the California redwoods. If a longer saw was needed, two shorter saws were sometimes brazed together.
One Person Saw (top) and a Two Person
Saw (bottom)
There are two basic saw patterns for the two-person saw: the felling pattern for felling trees and the bucking pattern for cutting up trees once they are on the ground. Each has characteristics suited to its use.
The felling saw has a concave back and is relatively light and flexible. It is light so less effort is needed to move it back and forth when felling a tree. It is flexible to conform to the arc a sawyer's arms take when sawing, and it is narrow tooth-to-back, enabling the sawyer to place a wedge in the cut behind the saw sooner than with a wide saw.
The bucking saw has a straight back. It is much thicker tooth-to-back than the felling saw, so it is heavier and stiffer. A bucking saw traditionally is used by one person, so it is a fairly stiff saw designed to help prevent buckling on the push stroke. The more weight put on a saw, the faster it will cut, so the weight of a bucking saw is an asset.
Felling Saw (top) and a Bucking Saw
(bottom)
The points of the teeth of nearly all crosscut saws lie on the arc of a circle. This result is a saw that cuts easier and faster than a straight saw. A circular contour is much simpler to maintain than a contour of any other shape (except straight).
There are three ways that the sides of a saw are finished (ground) when manufactured. Each finish affects the thickness of the saw in a particular way. These finishes are: flat, straight taper, and crescent taper.
A flat-ground saw has the same thickness everywhere. A taperground saw is thicker at the teeth than at the top edge of the saw. It is not as likely to bind in a cut, especially if the kerf is closing behind the saw as happens if the wood being cut is under compression. Another advantage is that a taperground saw requires less set than a flat-ground saw.
The difference between a straight taper and a crescent taper is in the lines of equithickness for the two saws: straight lines as opposed to lines concentric to the circle of the saw. This means that the teeth of a saw ground with a crescent taper are the same thickness, while the teeth of a saw ground with a straight taper are thicker toward the center of the saw.
Crescent taper ground
Straight taper ground
The uniform tooth thickness of a saw ground with a crescent taper is an obvious advantage over the varying tooth thickness of a saw ground with a straight taper. Trademarks indicating saws are ground with a crescent taper are Crescent Ground, Precision Ground, Segment Ground, and Arc Ground.