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[magazines/electronics-illustrated/toc/electronics-illustrated-september-1969.htm]
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A Guide to Hand Saws
Thinking of buying a new saw? Look over MI's comprehensive guide to the many
saws on the market.
by Clarence Martin
The hand saw dates back to the days of Neanderthal man and is not likely to be
eclipsed entirely by power tools in our lifetime. While powered saws have eliminated
much of the drudgery of construction, hand work still is preferred for many sawing
operations.
The earliest saws were crudely notched pieces of flint, but as long ago as the
1600's, there were saws similar in appearance, if not in quality, to those being
manufactured today. Until 1874, however, all Iron Age saws were turned out with
a straight back.
It was Henry Disston, inventor and industrialist, who decided that all that metal
at the toe of the blade wasn't necessary. Since its introduction, Disston's skewback
design has shared popularity with the straight back. The skewback is more flexible
and has an easier action than the straight back but many craftsmen prefer the stiff
feel of the straight back plus its adaptability as a straight edge.
The most widely used hand saws are the carpenter's crosscut saw and the rip saw.
An acceptable set of these saws for the active home craftsman would include one
rip saw, a 26-in. 8-point crosscut saw for general use and a 22- or 24-in. 10- or
11-point crosscut saw for joinery. These saws, of good quality, will cost around
$8 each.
If you can afford but one of these saws, a crosscut saw in the 26'in. length
and with coarse teeth (7-8 points) should be chosen. While designed for rough cutting
across the grain, it can be used for ripping in an emergency.
The teeth on the crosscut saw have their points sprung alternately to one side
or the other to prevent binding or pinching in the kerf.
In use, the crosscut saw initially is guided along the waste edge of the line
to be cut with the thumb held against the side of the blade. The blade is drawn
back lightly several times over the edge of the board until a good kerf is established.
Only then should the saw, held at about a 45° angle, be pushed forward and with
only enough pressure to make it cut smoothly. After the first few short strokes,
the entire length of the blade should be utilized.
When nearly through, the piece being cut must be supported to prevent its weight
from splitting the wood.
The rip saw is similar in construction to the crosscut saw except for the teeth.
These are filed square across their tips and cut on the push stroke only. When rip
sawing, the saw is held at a 60° angle. Otherwise, the procedure is the same
as with the crosscut saw. It may be necessary to place a wedge behind the cut if
the saw binds.
Good quality blades are ground to taper from the cutting edge to the back and
from the handle or heel toward the toe.
The back saw is used whenever a fine, accurate cut is needed. It has fine teeth
(12-14 points) that will either rip or cross cut. These, combined with a stiffening
rib along the back of its thin blade, make it ideal for joinery, stair work, inside
cabinet work and any other area where a close, precision cut is required.
Carpenters sometimes use the back saw together with a homemade miter box to make
square or angular cuts.
The dovetail saw also has a reinforced back and was designed originally for cutting
dovetail joints. it may be used for fine work in cramped quarters.
A plumber's saw is an all-purpose saw that looks like a rip or crosscut saw and
costs about the same. In addition to wood, it will cut lightweight sheet metal,
lead and other soft metals, including an occasional nail.
Top: a good saw should show clearance at toe and heel when tested on a flat
board as shown.
Below: a properly set saw will allow a needle to slide down on the teeth when
tipped up.
The flooring saw has teeth running up and around its reverse-curve toe. it can
be used to make a starting hole in a flat expanse. Once started, the saw is removed
from teh slit, flopped over and the regular teeth used to complete the cut.
Circles and curves are cut with a coping saw. Blades come in a variety of tooth
sizes, are either loop or pin ended and may be used at any angle.
The teeth of the coping saw may point either toward or away from the handle as
preferred. If away, cutting occurs on the push stroke; if toward, on the pull stroke.
The compass saw is used to cut holes and irregular curves, such as those needed
for plumbing or lighting fixtures. it rips or cross cuts. Inside holes normally
require a bored hole in the waste stock for starting the cut.
The keyhole saw is similar to the compass saw but has a smaller, narrower blade.
As its name implies, it was designed for use in fitting locks in doors, but may
be used for cutting any close holes or curves.
Keyhole and compass saws are priced around $1.50 and a nested set with three
interchangeable blades will cost about $3.50.
The one- and two-man saws used by loggers have just about been replaced by the
chain saw. The old-style buck saw and the newer bow saw, however, still are much
in use for cutting wood for stove or fireplace. They are favored particularly by
those who enjoy the outdoors and exercise.
Pruning saws for use on trees or shrubs may be a modified bow-saw type with a
blade about 21 in. long, the bow more nearly in the shape of an L than a C. They
are available also with a curved 14-in. blade that cuts on the pull stroke. Another
version is double-edged, with one edge fine and the other coarse.
Modern living has produced the frozen-food saw and has brought the butcher's
saw into the home. Both are similar to the hack saw.
Most hack saws in use today have an adjustable frame that will accept blades
from eight to 12 in. in length. These may be inserted in anyone of four directions
in relation to the frame.
Hack saw blades have 14, 18, 24 or 32 teeth to the inch. Coarse blades are used
for rough or fast work while the 32-tooth variety is used on fine work and tubing.
A rule of thumb for selecting a metal-cutting blade is that at least two full
teeth must rest on the stock being cut (or the teeth will be stripped). Therefore,
stock 1/16-in. thick would require a 32-tooth blade and stock 1/8-in. thick an 18-tooth
blade. A finer blade should be used when in doubt.
In use, the initial cut with a hack-saw blade is guided with the thumb. After
the cut is started, the guide hand is moved to the front of the saw frame to aid
in equalizing the downward pressure needed on the forward stroke and in releasing
it on the return. Sawing should be at about 50 strokes per minute. The saw should
be guided through the cut by the blade and not the frame. Use the full length of
the blade, be alert for breakage and take care not to follow through at the final
stroke.
The jeweler's saw is similar in shape to the coping saw except that it has an
adjustable frame and uses straight-end blades. The blades are secured in the frame
with lock nuts and the frame is adjusted until the blade is tight enough to give
off a musical twang. The teeth point toward the handle and are lubricated with beeswax
when cutting metal, which is held usually in a notched board. Blades may be obtained
in such a variety of thicknesses and teeth that almost any material may be cut to
any desired shape.
It is difficult to imagine any sawing job in ordinary unhardened materials that
could not be accomplished with the aid of the saws covered here.
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