Fig. 1. Saw hammers.
Excerpted from The Chronicle, Vol. XIX, no. 2, June 1966
By R.D. Morris
The four hammers in fig. 1 are saw hammers and are often mistaken for file maker's hammers. These, as well as some of the saw gauges in my collection, are from the J. H. Miner Saw Manufacturing Company, LumÂberton, Mississippi. Our last saw mill of the C. L. Morris Lumber Company, Plymouth, Indiana, was disÂmantled in 1932 and the practice of hammering was about discontinued. My father learned the saw filing trade in about 1901 at the Miner saw manufacturing company. My own experience with saw hammering has been very limited. In my youth I spent a lot of time after school observing our filer at work (the filing room was then the only heated room in winter) but only tried hammering on small saws in an emergency when there was an absence of the filer and something went wrong in the mill.
In fig. 1, the hammer on the left weighs 5-1/4 pounds and has a slight oval face. The handle is a replacement. The hammer at the top weighs 3-1/4 pounds and is a taperÂed octagon shape with a flat face. The one on the bottom has a curved taper octagon shape with an oval face, weight 3 pounds. The original handles that are on the top and bottom hammers are quite slender and have a delicate neck. This is quite normal as the hammers were used only with the utmost caution in striking. The weight of the head did the work instead of the strength of the arm.
Fig. 2. Saw gauges.
Fig. 2, shows some of the saw gauges used in locating the spots to hammer. Some of these have J. H. Miner Saw Manufacturing Company, Lumberton, Mississippi, stamped on them.
The principal use of the saw hammer was to mainÂtain the proper tension on the circle saws. By tension is meant the behavior of the saw in relation to the arbor speed and the centrifugal force and friction of the outer rim. A circle saw is designed to run at a determined speed. An increase of speed can bring unsatisfactory use. When this happens, or resulting damage occurs the saw hammer is put to use to attempt a correction. Saws on a band mill are rolled instead of hammered.
Damage to a saw usually shows up in a wobble, which does not produce the uniform thickness lumber the sawyer is trying to cut. Continued use of a damaged saw makes it heat up and the wobble gets worse to the point of danger. A wobble may be eliminated by hammering. To find the spot to hammer is where the skill of the saw filer is tested. Gauges (actually straight edges) are brought into use. A variety of sizes and curves are reÂquired for different saws. I have a set of over a dozen. When an unevenness is sighted under the gauge it is chalked with a circle or mark and the plan of hammering is decided.
Fig. 3. ''This shows saw hanging on the hook to test it for ridges, and also locating the full place on a saw that is raised. Always spring or pull a dished saw as near straight as possible, then the straightedge applied as at X and J will show where the full place is. Dished saws are usually high at the collar. Do not test a saw in this position for tension. The rim can be tested with short straightedge and ridges located. Always begin on the high side of a saw."
Hammering is a reshuffling of the iron molecules to stretch the steel properly. A small or large spot deterÂmines the hammer and the skill determines the blow. There are flat and oval faced hammers. Hammer blows must be judiciously placed on saws or too heavy a blow can cut or damage the saw. The hardness of steel in the saw varies considerably. An iron pad is often used beÂtween saw and hammer to prevent a cut.
Hammering equipment includes a carriage frame and pivot hook for the circle saw to be gauged and rotated over the saw anvil. A 10 by 10 inch or heavier anvil with a high quality face is used. Hammering is only a part of the work of the filer. More work is done on the teeth of the saw. They are shaped by "gumming," swaged on the tooth and filed or ground sharp. All of the phases of the work have their own tools and are seldom adaptable for any other use.
Fig. 4. "The only way to correctly test the tension in a circular saw. It is raised clear of the anvil, supported on the hip. The 24" straightedge or gauge, if using a gauge, is applied as shown at B. This is at right angles to the support of the saw. Do not vary the rim end more than 4" either to or from you, before moving the saw."
Perfection only is expected of a filer and he has to have a natural talent plus sufficient apprentice work to qualify for his job. Once his ability is established he can demand and get top pay in the lumbering industry.
Figs 3 and 4 show the two methods by which the saw is placed to use the gauge. The captions under each figure explain the process and these two drawings are from the booklet "The Filer's Success" by J. H. Miner.