 |
Power Saw Injuries
Power saws are extremely useful tools, enabling all types
of materials to be cut and shaped. However, they also have the potential
to cause serious hand injuries. The hands are used to guide pieces into
the saw, and thus they can be vulnerable.
The severity of the injury can vary tremendously, depending
on the specific level at which the injury occurs (fingertip vs. finger
vs. hand vs. forearm), the depth of the injury (skin only vs. tendons,
nerves, arteries, and bone), and also characteristics of the saw, such
as the blade thickness, tooth pattern, and type and force of the saw.
Jigsaws will tend to have a finer, sharper cut, whereas a chain saw
is much more powerful with an aggressive blade that can tear out more
tissue from the hand or finger.
Kerf (width of cut made
by saw blade)
A saw blade is often rated by its kerf, which describes
the width of the cut made by the blade (see Figure 1). A bigger kerf
means that a thicker or wider defect will be cut out by the path of
the saw blade. Smaller kerfs leave a narrower defect in the material
that they cut. The kerf may be wider than the saw blade because the
cutting teeth of the blade may be angled outwards. The shape and pattern
of the teeth will also vary depending on the particular application
of the saw (eg fine cuts as with a jigsaw, or bigger teeth with ripsaws
to cut with the grain or crosscut against the grain of the wood). Saws
will vary with regard to their action, such as the rotating blade of
a circular saw or table saw, the reciprocating action of a jigsaw or
scroll saw, and the continuous line of movement of a band saw or a
chain saw. Use of the proper type of saw and blade for the intended
task is important to avoid binding or kicking back of material, or
other problems that can cause injury.
Any structure that comes into contact with the saw blade can potentially
be injured. Superficial scrapes or more severe cuts can damage the
skin. Sometimes a large area of skin can be torn off. Deeper injuries
can damage the tendons and muscles that move the fingers, thumb, and
wrist, affecting the way they move. Nerves may be cut, resulting in
loss of feeling and/or loss of ability to control certain muscles.
Circulation may be lost if the arteries are injured. Fractures may
result, which can be in the shaft of the bone or in the joint, and
sometimes with loss of bone substance. Amputations are also possible.
With certain types of saws, there may be much more shredding as opposed
to a sharp, fine cut. Electric shocks and burns can also occur with
the operation of a power saw.
Simple cuts may be treated with stitches or bandages. Larger areas
of skin loss may need a skin graft for coverage. Tendon and nerve
injuries may need to be repaired, but if too much shredding has occurred
or there is excessive loss of the tendon and/or nerve tissue, repair
may not be feasible. Fractures may need repair with pins, wires,
or plates and screws. If a joint is severely damaged, it may need
to be fused permanently. Some amputations may be able to be replanted,
but if there is too much shredding, it may not be feasible. Amputation
of a single finger may be better treated by leaving it off, as the
reattached finger may impair the function of the rest of the hand.
The goal is to optimize the overall function of the hand, but residual
impairment (weakness, stiffness, numbness, loss of parts) is possible
with many of these types of injuries.
Follow all the safety instructions provided for your power saw. Do
not override safety guards; they are there for your protection.
- Never look away from your work.
- Never use your hands to clear the scraps from a sawing
worktable, instead, use a long stick.
- Do not wear loose clothing or jewelry around the wrists.
- Keep your finger off the trigger when carrying a portable
power saw.
- Do not use the saw to perform a task for which it
was not designed.
- Use the correct blade for the application. Set it
for the correct depth, to minimize the amount of exposed blade and
reduce the potential for binding.
- Use sharp blades. Dull blades cause binding, stalling
and possible kickback.
- When starting, let the saw reach full speed before
cutting and support the work firmly so it will not shift.
- If the saw stalls, switch off the power and unplug
the tool before trying to restart it.
- When working with metal, secure the metal materials
with clamps or in a machinist’s vise to keep it from moving.
- Check for proper blade guard operation before each
cut.
- When starting or stopping the saw, make sure the work
is not touching the blade.
- Lower a table saw blade below the table top when finished.
- Keep a clear head, concentrate, and DO NOT DRINK ALCOHOL
before using a power saw!
If you are injured seek prompt medical attention. Delay
in treatment can lead to a higher risk of infection or tissue loss.
The damage done to a finger, hand or any site often exceeds what may
be initially apparent due to the force of these types of injuries.
Power saws can cause very serious damage that may result in permanent
loss of motion, feeling, and strength, or even in amputation. Prevention
is far better than trying to try to deal with the aftermath of an injury.
© 2007 American Society for Surgery of the Hand
Developed by the ASSH Public Education Committee
View a PDF of this content
MedlinePlus®
National Library of Medicine
National Institutes of Health
amputation, prosthetics, prosthesis
|
|
