Saw Grinds

The sides of vintage saws were finished, or ground, in three different ways. Each method affected the thickness of the saw in a particular way and has major implications for the overall quality of the saw. These grinding methods are flat, straight taper, and crescent taper (figure 5).

Figure 5—A comparison of straight–taper–ground and crescent–taper–ground saws.
Neither is manufactured today. Today's saws are flat ground, a design
that is inferior to tapered saws.

Flat Ground

On a flat–ground saw, the metal's thickness is the same throughout. Saws manufactured today are flat ground.

Flat–ground saws are considered the least desirable. The main disadvantage is that it takes more set to enable the saw to clear the kerf (the slot the saw cuts in the wood). Set is the cutter tooth's offset from the plane of the saw. The kerf has to be wider for flat–ground saws, and more energy is required to use the saw (figure 6).

Figure 6—A comparison between
taper–ground and flat–ground saws.
Taper–ground saws are less likely to bind.

Straight Taper Ground

Straight-taper–ground saws have an advantage over flat ground saws because the saw is thinner at the back than at the teeth. The back of the saw has more clearance, reducing binding.

The teeth of straight–taper–ground saws are thicker near the center of the saw than along either end. Straight–taper–ground saws require less set than flat–ground saws.

Crescent Taper Ground

The best vintage saws were crescent taper ground. Warren Miller explains the difference between straight taper and crescent taper saws in the Crosscut Saw Manual (1977, rev. 2003): "The difference between the straight taper and crescent taper is that the lines of equithickness for the straight taper–ground saw are straight and those for the crescent–taper–ground saw are concentric to the circle of the saw. This means that the teeth of the crescent–taper–ground saw are all the same thickness; whereas the teeth of the straight–taper–ground saw are thicker toward the center of the saw."

Saw manufacturing companies called crescent–taper–ground saws by different trade names: Crescent Ground (Simonds), Improved Ground (Disston), and Segment Ground (Atkins). Other names included Precision Ground and Arc Ground (figure 7).

Figure 7—Companies like Simonds heavily promoted their Crescent Ground
crosscut saws as the best ever made. The numbers refer to the gauge, or
thickness, of the steel.—Simonds saws and knives catalog (1919), with permission of
Roger K. Smith, Athol, MA

The thinnest part of a crescent ground saw is at the back center, which is often 4 or 5 gauges thinner than the teeth. If you hold one of these saws and sight down its back you can see the taper. You can feel the change in thickness (figure 5).

Crescent–taper–ground saws offer the saw the most clearance in the kerf of any of the grinds. These saws require the least amount of set, allowing the narrowest kerf.