A simple way to think of San Mai III® blade construction
is to imagine a sandwich: The meat center is hard, high carbon steel and
the pieces of bread on either side are the lower-carbon, tough side panels.
The edge of the blade should be hard to maximize edge holding ability, but
if the entire blade was hard it could be damaged during the rigors of battle.
For ultimate toughness the body of the blade must be able to withstand impact
and lateral stresses. Toughness is generally associated with "softness"
and "flexibility" in steel, so that, surprisingly, if a blade
is made "tough" the edge won't be hard enough to offer superior
edge holding. San Mai III® blades provides a blade with hard (higher carbon)
steel in the middle for a keen, long lasting edge and tougher (lower-carbon)
steel along the sides for flexibility.
These two grinds are quite similar. They are both actually "flat",
as opposed to concave (hollow ground) or convex. However, a "Flat ground"
blade is typically ground uniformly from the blade back right to the edge.
Where as in a "Saber ground" blade, typically only half the width
of the blade is ground. The rest remains full thickness, like a traditional
saber, hence the name.
Cantled Edge is the most widely used edge configuration. It consists
of a final grind along the very edge of the primary grind. This final grind
forms the sharp edge of the knife. One of the main reasons for its popularity
is that the cantled edge is fairly simple to apply by hand or machine. It
is also relatively easy to control the angle of the cantle to achieve a
desired degree of sturdiness or fineness to the finished edge.
This is simply a design feature to add interest and to lighten the blade.