|Machine Hazards > Rotary and Reciprocating Movements
|All machines operate by rotating or reciprocating motion or by a
combination of these motions. Reciprocating movement is back-and-forth or up-and-down motion.
Rotary cutting and shearing mechanisms, rotating wood stock, flywheels, shaft ends, and
spindles all rotate. Rotating action is hazardous regardless of the speed, size, or
surface finish of the moving part.
- Rotating parts and shafts, such as stock projecting from the chuck of a lathe, can
catch hair or clothing and draw the operator in. This can seriously mangle or crush the operator.
- Operators can be struck
by a projecting bolt or key.
- Rotating parts and stock can force an arm or hand into a dangerous position, breaking bones and
lacerating or severing a hand or other parts of a limb.
- Operators can be caught and
crushed by reciprocating movement when the moving part approaches or crosses a
fixed part of the machine (Fig. 1).
Fig 1 - Reciprocating
Work Practice Controls
- Machine Guarding - Guards are now standard equipment on most woodworking machines. If you
purchase a machine that does not come equipped with a guard, install
one. Contact the manufacturer of the machine to see if appropriate
available for the equipment. If not, use this guide to help you determine
the appropriate guard to install. Because woodworking equipment is dangerous, guards
should always be designed and installed by technically competent and qualified
persons. In addition, it is always a good idea to have the equipment
manufacturer review proposed guard designs to ensure that the guard will
adequately protect employees and allow safe operation of the equipment.
- There are many ways to guard machines. The type of operation, size or shape of stock, work
being performed on the material, method of handling, and production requirements are some of the
factors that help determine the appropriate safe-guarding method for an
individual machine. All moving machine parts that may cause injury must
be safeguarded. This includes the point of operation, the power transmission apparatus, and
rotary or reciprocating parts. Table 1 describes three types of machine guards commonly used on woodworking
machinery: fixed, adjustable, and self-adjusting.
To be effective, a guard should prevent
employees from contacting the dangerous parts of the machines, and it should be secure. This is not
always possible, as in the case of the radial arm saw. Regardless, workers should not be able to
easily bypass, remove, or otherwise tamper with the guard. In protecting the worker, however, the guard
must not create additional hazards, nor prevent the worker from performing the job.
- Make sure that guards are in working order and that they are appropriate and practical for the
machinery. Guards must have adequate strength to resist blows and strains and should be constructed
to protect operators from flying splinters and machine parts such as broken saw teeth, cutting
heads, and tools.
- The Rough Mill and Production
sections provide more detailed information on methods of machine
guarding (including construction of guards), and guard types for specific woodworking machines.
- Additional methods for safeguarding machines include guarding by location or distance, feeding methods,
and appropriate placement of controls. However, none of these methods should replace machine
guards. It is always important to provide a guard or barrier that prevents access to the danger area.
Table 2 describes these
other safeguarding methods.
- Train workers on machine use and allow only
trained and authorized workers to operate
and maintain the equipment. Workers should
understand the purpose and function of all
controls on the machine, should know how to
stop the equipment in an emergency, and should
be trained on the safety procedures for special set-ups.
Operator training should include hazards associated
with the machine, how the safeguards protect
the worker from these hazards, under what circumstances
the guard may be removed (usually just for
maintenance), and what to do if the guard is
damaged or not functioning properly.
Employees should be able to demonstrate their
ability to run the machine with all safety
precautions and mechanisms in place.
Frequently inspect equipment and guards.
Ensure that: (1) the operator and machine are
equipped with the safety accessories suitable for
the hazards of the job, (2) the machine and
safety equipment are in proper working condition,
and (3) the machine operator is properly
trained. Document the inspections and keep the
records. Documentation should identify the
machine, inspection date, problems noted, and
corrective action taken. Noting problems helps
to ensure that corrective action will be taken,
that operators on all shifts will be made aware of
any potential danger, and that any pattern of
repeat problems on a particular machine can be
detected and resolved as early as possible.
Use equipment only when guards are in place
and in working order. A worker should not be
allowed to operate a piece of woodworking
equipment if the guard or any other safety device, return device, spreader, anti-kickback
fingers apparatus, guard on in-running rolls, or
gauge or rip fence is not functioning properly.
When guards cannot be used (during rabbeting
or dadoing, for instance), you must provide combs, featherboards, or suitable jigs for
holding the stock.
Never leave a machine unattended in the
“on” position. Make sure that workers know
never to leave a machine that has been turned
off but is still coasting.
Maintain proper housekeeping. Workers have
been injured by tripping and then falling onto
the blades of saws. You must keep floors and
aisles in good repair and free from debris, dust,
protruding nails, unevenness, or other tripping
hazards. Do not use compressed air to blow
away chips and debris. Make sure you have a
Do not allow workers to wear loose clothing
or long hair. Loose clothing or long hair can be
easily caught up in rotating parts.
Use appropriate personal protective equipment.