The Saw
By: The Working Man



A saw is a tool specifically made to cut through softer objects
than itself. It usually is a thin, long metal piece, usually
serrated, that has an edge for cutting on one side and is fitted
with a handle. There are many different types of saws and they
can be powered by hand, steam, water, electricity or some other
type of power.

The saw nowadays is made in such a way as to have each tooth of
the edge bent at a precise angle called a "set". The set of the
teeth determines the cut the saw makes. Most saw blades have the
teeth set so that the saw cuts a wide kerf so that the blade can
be easily removed from the object being cut.


Here are the major types of saws available today:

- Hand saw
- Back saw
- Bow saw
- Circular saw
- Reciprocating saw
- Band saw

The saw was invented by Lu Ban, according to Chinese tradition.
According to the Greek, Perdix, the nephew of Daedalos was the
saw's inventor. But more likely the saw was invented a very long
time ago and probably evolved from a Neolithic tool or bone
tools. Probably the first saw was made from the jaw bone of a
large plant eater.


Here are names for the different parts of the saw:

- Heel: The end closest to the handle.

- Toe: The end farthest from the handle.

- Front: The side with the teeth (the "bottom edge")

- Back: Opposite the front ("top edge")

- Teeth: Small sharp points along the cutting side of the saw

- Gullet: Valley between the points of the teeth

- Fleam: The angle of the faces of the teeth relative to a line
perpendicular to the face of the saw.

- Rake: The angle of the front face of the tooth relative to a
line perpendicular to the length of the saw. Teeth designed to
cut with the grain (ripping) are generally steeper than teeth
designed to cut across the grain (crosscutting)

- Points per inch (25 mm): The most common measurement of the
frequency of teeth on a saw blade. This is measured by setting
the tip, or point, of one tooth at the zero point on a ruler, and
then counting how many points are contained within one inch (25
mm) of length, counting inclusively. There will always be one
more point per inch than there are teeth per inch (e.g., a saw
with 14 points per inch will have 13 teeth per inch; a saw with
10 points per inch will have 9 teeth per inch). Some saws do not
have the same number of teeth per inch throughout their entire
length, but the vast majority does.

- Teeth Per inch: Another common measurement of the amount of
teeth residing in any one inch length of a saw blade. Usually
abbreviated as TPI, e.g. a blade consisting of 18TPI (Teeth Per
Inch).

- Kerf: Width of the saw cut. On most saws the kerf is wider than
the saw blade because the teeth are flared out sideways (set).
This allows the blade to move through the cut easily without
getting stuck (binding).

However, some saws are made so that the teeth have no set on one
side. This is done so that the saw can lie flat on a surface and
cut along the surface without scratching it. These are referred
to as flush cutting saws. The term kerf is often used to mean the
width of the saw blade. However it is the width of the cut so it
is the width of the blade plus any wobble created during cutting
plus any material pulled out of the sides of the cut. This
distinction can be extremely important. If you try to use a blade
that is too thin you can get excessive wobble and actually get a
wider kerf.


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