Why Is A Taper Ground, Champion Tooth Saw The Best?

Why Is A Taper Ground, Champion Tooth Saw The Best?

If you read our post “HOW TO BUY A REAL BUCKING CROSSCUT SAW,” a simple flat carbon steel saws may be inexpensive, easy to fabricate, cheaply produced, but I would not recommend using them for logging or bucking all the time, but I would recommend hanging them on a wall for a showcase. I have acquired an authentic, 2 person lanced tooth pattern, straight back bucking saw from my area, a historical logging county, around the 1940’s. The bucking saw I have is flat carbon steel saw, a poor man’s saw at that time. This saw is rusted, the set is off, and worn. Inexpensive saws of the 1940’s and same as today, they do cut wood, for short duty life, yet they are NOT Survivor Duty quality for they are supply chain dependent. See Figure (1).

Figure 1

For the kerf set and to avoid binding, the teeth on this saw requires a wide set to compensate for flat gauge steel. The “poor man’s saw” simply will not last if we need a saw that can cut wood 360 days of the year for heating, cooking, and for a foundry.

Survivor Duty then acquired an authentic, premium Northwest logging saw in pristine condition with no rust and never used. We are reverse engineering this saw so we can bring back high quality logging saws of the past. See Figure (2).

Figure 2

This authentic saw has a high chromium content, “Silver Steel,” (Tool Steel), that will not rust quickly and highly durability through gas tempering, (ductile and high tensile strength), a crescent ground taper and the heavy duty Champion, beveled tooth pattern for tough cross cutting stresses. The back of the blade is that of a combination bucking saw and falling saw with a slight concave back. The slight concave back gives room for the shim when falling a tree, yet the width of the blade is wide enough to buck logs.

Over the internet, there are amateurs attempting to sharpen antique cross cut saws by butchering the teeth by grinding them down with a joiner or removing the hardness by blow torching the teeth. The profile of the teeth and the hardness is critical for the performance of the saw. The saw in Figure (2), was never used so we have the original tooth profile. This is why we recommend a new saw, fabricated correctly, then a worn old saw that was mishandled by excessive sharpening or over setting through the years. A new saw used for a season of cutting will have slight wear on the cutting teeth and raker. Sharpening the teeth for the first time only requires a small amount of metal removed to form a new sharp point and the Champion pattern tooth set is the easiest. Since we will grind a new point for the cutters, say less than 0.03 in. the raker will also have to set lower since the cutters were lowered by grinding. The profile of the original cutter and raker teeth, from the gullet to the crest, must hold for a long lasting saw. If we keep grinding to a minimum, we will prevent tooth patterns degradation and hold the joiner circumference tangent. See Figure (3).

Figure 3

In Figure (4), illustrates the cutter profiles to the Champion style raker. Skill shaping the cutter teeth’s with minimum loss of metal. Also, the swedge of only .003 must be maintained if we are re-shaping the cutting teeth. The slight cutter teeth swedge is needed for the raker so to cut the grove shaving. The swedge is the width of the raker gauge  + .003 of an inch on both sides. Most old rusted saws dating back 75 years were most often mishandled when sharpening. To regain the original profiles one would require punching new teeth. Heat treating teeth in order to sharpen will weaken the grains in the steel that will most likely cause teeth to break if too brittle wear too rapidly if too ductile. If all the teeth are not handled the same, then the sets will fall off the scale and the teeth will fall out of circumference.

Figure 4

In figure (5), Survivor Duty design team sketching the counters of the raker in relation to the original 1900’s bucking saw tooth profiles. In ref. (A), we see the setback of the raker in the original tooth profile. In ref. (B), an exaggerated example of over filing. From the gullet to the crest of the cutter lost 0.15 of an inch. If the inexperienced simply over filed a new point on the cutter teeth, the raker will be set to high. If the raker teeth are compensated to match the cutter teeth, the profiles of both teeth will change thus decreasing the efficiency of the cut. The gullets will be shallower thus removing less wood shavings from the cut that will bind in the kerf.

Figure 5

Crescent Grinding

Other then the quality of steel used back in the 1900’s, the grinding process used to taper the cutter head made a fair saw a great saw. The steel process and blade grinding techniques were all patented at the time. Those who did not own the rights to fabricate and market crescent tapered saws had to make up for the kerf cut with wide swedged teeth that needed consistent setting.

In figure (6), the first grind is the to set the end taper one side, then ground on the opposite side. In this image, the thickness is exaggerated so to demonstrate the contours.

Figure 6

In figure (7), the crescent taper is applied leaving the cutting head and even gauge then tapered back to the base of the saw.

Figure (7)

New two person cross cut saws sold today do not incorporate this form of tapering due to the cost. Nor are saws made of quality steel. Survivor Duty would like to return the original product back to market. They will not be inexpensive.

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