Accident Prevention Manual
for Business & Industry:
Engineering & Technology
13th edition
National Safety Council
Compiled by
Dr. S.D. Allen Iske, Associate Professor
University of Central Missouri
CHAPTER 21
WOODWORKING MACHINERY
General Safety Principles
• Use equipment that meets OSHA, ANSI, and NFPA
National Electrical Code standards.
• Specify needs during purchasing.
• Maintain all machines so that while they are running at full
or idle speed and with the largest cutting tool attached,
they are free of excessive noise and vibration.
• Level all machines, including portable or mobile ones.
• Secure machines to the floor or other foundations, when
possible, to eliminate movement.
General Safety Principles (Cont.)
• Secure small units to benches or stands.
• Make sure the machine is constructed so that tools that
are too large cannot be mounted.
• Ensure that all arbors and mandrels have firm and secure
bearings and are free from slip or play.
• Regularly check the adjustment of all safety devices.
• Those involving electrical circuits should be actuated to make sure
they operate properly.
• Operators should lock out machines before cleaning, adjusting, or
maintaining them.
General Safety Principles (Cont.)
• Keep loose clothing, long hair, jewelry, and gloves away
from rotating parts of machinery.
• especially from nips points and the point of operation
• After the equipment has been completely stopped, clean
work surfaces with a brush, not with the hand or a
compressed air nozzle.
• If possible, make adjustments only while the machine is
not running.
General Safety Principles (Cont.)
• Electrical equipment
• All metal framework on electrically driven machines should be
grounded, including the motor.
• Comply with NFPA 70, National Electric Code.
• NFPA 70 includes the following provisions:
• The machine shall have a cutoff devices (EMERGENCY STOP) within
reach of the operator in the normal operating position.
• Electrically driven equipment shall be controlled with a magnetic switch
or other device that prevents automatic restart after power failure.
General Safety Principles (Cont.)
• Example of devices stopping restart
General Safety Principles (Cont.)
• Electrical equipment (cont.)
• Position clearly marked power and operating controls within reach
of the operator and away from hazards.
• Protect operating controls against unexpected or accidental
activation.
• Provide a positive means (lockout) for rendering the controls
inoperative in each machine operated by an electric motor.
• If the machine does not have a power disconnect to lock it in the OFF
position, unplug the cord and place a small padlock through the holes in
the plug.
• Install an electric motor break on machines that have excessive
coasting time.
General Safety Principles (Cont.)
General Safety Principles (Cont.)
• Guards
• Enclose or guard all belts, shafts, gears, and other moving parts so
no hazard is present for the operator.
• Because most woodworking operations involve cutting, it is
necessary, although often difficult, to provide guards at the point of
operation.
General Safety Principles (Cont.)
• Guards (cont.)
• Point-of-Operation Guards must:
1. be moveable to accommodate the wood.
2. balanced so as not to impede the operations.
3. strong enough to provide protection to the operator.
• Whenever possible, completely cover blades and cutting edges at
the point of operation.
General Safety Principles (Cont.)
• Work areas
• Provide ample work space around each machine.
• See Table 21–A for recommendations.
• Make adjustments if the worker is taller or shorter than average.
• Perform routine floor maintenance in the work area to prevent
splintering and protruding nails.
• Install slip-resistant flooring and mark aisleways with paint, railings,
or other markings.
General Safety Principles (Cont.)
General Safety Principles (Cont.)
• Work areas (cont.)
• Maintain good housekeeping to prevent dust and chip
accumulation.
• A clean operation makes work easier and helps prevent fire and
dust explosions.
• Adequately light the work area and adjacent stock areas.
• General illumination of 80 to 100 fc (861 to 1076 lux) will pay dividends
in both accident prevention and efficiency.
General Safety Principles (Cont.)
• Materials handling
• Facility layout should encourage an even flow of materials and
keep backtracking and crisscrossing to a minimum.
• Operators shouldn’t have to stand in or near aisles.
• Arrange the machines so that the materials handled by the operator
require minimum movement and changes of heights.
• This applies to both incoming supply and outgoing stock.
General Safety Principles (Cont.)
• Inspection
• Make safety checks by putting machines through trial runs before
beginning a job and after each new setup.
• The operator should inspect the machine at each new setup and at
the start of each shift.
• The inspection process should follow the manufacturer’s
recommendations and requirements and flow patterns of the
workplace.
General Safety Principles (Cont.)
• Hearing protection and conservation
• Most woodworking machinery creates high noise levels requiring
that employers establish and maintain hearing conservation
programs.
• Management should hire a qualified person or IH person to take
sound-level measurements.
• If sound level readings (dBA, slow response) exceed 85 dBA over
an 8-hour period, that worker must be included in the hearing
conservation program.
General Safety Principles (Cont.)
• Fine dust
• When woodworking processes create fine dusts, the EHS
professional should have the amount sampled.
• Observe established threshold limit values (TLVs) and maximum
permitted exposure (MPE) levels.
• Fine dust can be a health, fire, or explosion hazard.
• For workers’ protection, respirators that reduce inhalation of various
types of nuisance dust are available.
General Safety Principles (Cont.)
• Personal protective equipment
• All individuals in the work area should wear eye protection.
• ANSI Z87.1 compliant goggles are recommended.
• Some operations may require operators to wear face shields with
safety glasses.
• Workers should wear hair nets or caps to protect long hair.
• Workers can protect their hands with gloves when handling wood
but should avoid gloves near moving parts.
• Where there is the danger of kickback, workers should wear proper
abdominal guards.
General Safety Principles (Cont.)
• Standards and codes
• There are a number of OSHA standards, such as 29 CFR 1910.23,
Woodworking Machine Requirements, that state required safety
features for woodworking machines.
• Some states and other jurisdiction have codes that specify
requirements.
• The National Safety Council library has available a number of
occupational safety and health data sheets on woodworking
machines.
Saws
• All saws pose potential hazards for operators. EHS
professionals can minimize these hazards by:
1.
2.
3.
providing training for operators.
ensuring that all machinery is properly guarded.
making sure that all ANSI, NFPA, and government regulations
are followed.
Saws (Cont.)
• Circular saws
• Blade cuts or abrasions and kickbacks are among the most
frequent incidents involving circular saws.
• These can be minimized by proper guarding and training and by
enforcing safe work procedures.
• Circular saws are designed to permit a wide range of cutting tasks.
• The problem with saws, as with most multiple-use equipment, is the
difficulty in designing one guard that offers maximum protection for all
types of tasks.
Saws (Cont.)
Circular Saws
21-5 and 21-6
Saws (Cont.)
• Circular saws—kickback and ripping
• A kickback occurs during a ripping operation when part or all of the
work piece is violently thrown back to the operator
• To avoid kickbacks operators should do the following:
• maintain the rip fence parallel to the blade.
• keep the blade sharp and replace anti-kickback pawls when they
become dull.
• keep blade’s guards, spreaders, and anti-kickback pawls in place and
operating properly.
Saws (Cont.)
• Circular Saws—kickbacks and ripping (cont.)
• Prevention methods:
• Cut only material that is seasoned, dry, and flat and that has a straight
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•
•
•
edge to guide it along the rip fence.
Release work only when it has been pushed completely past the blade.
Use a push stick for ripping widths of 2 to 6 in. and auxiliary fence and
push block for ripping widths narrower than 2 in.
Allow the cutoff piece to be unconfined when ripping or cross cutting.
Apply the feed force to the section of the work piece.
Saws
(Cont.)
Ripping
procedure
Saws (Cont.)
• Circular saws—guards
• Supervisors and operators should check that the spreader is rigidly
mounted and fully elevated at least 2 in.
• Guard a circular table saw, used for cutting, with a hood that
completely covers the blade projecting above the table.
• Operators should let the guard ride the stock being cut, adjusting to
the thickness of the stock.
Saws (Cont.)
Saws (Cont.)
Saws (Cont.)
• Circular saws—rabbeting and dadoing
• When rabbeting and dadoing, it is impossible to use a spreader
and often impractical to use the standard hood guard.
• These operations can be guarded by a jig that slides in the groves of the
transverse guide.
• The hazards of these jobs justify special guarding, especially when
work is being done on small stock.
• Operators can use feather boards to hold the work to the table and
against the fence as it is fed past the dado head.
Saws (Cont.)
Saws (Cont.)
• Circular Saws—proper operating methods
• Only authorized persons should operate circular saws.
• A saw in good condition and running at the correct speed should
cut easily.
• If a saw does not cut as fast as it should, or if it doesn’t saw a clean,
straight line, the saw blade or running speed may be improperly set.
• Never use a blade larger than what is allowed for the mandrel’s
speed.
• Use the right saw for the right job.
• Take into consideration blade height.
• Operators should stop a circular table saw before leaving it.
Saws (Cont.)
Saws (Cont.)
• Circular Saws—selection and maintenance
• The characteristics and conditions of circular-saw blades are
important safety factors for the operators who use them.
• When operators alter the original design of a saw they seriously affect
the saw’s efficiency and safety.
• There are numerous conditions which may cause unsafe, difficult,
or unsatisfactory operation:
• blade out of round
• blade not straight
• improper or uneven set
• dull blades
• improper bushings
• cracked blades
Saws (Cont.)
Saws (Cont.)
Saws (Cont.)
Saws (Cont.)
• Overhead swing saws and
straight-line pull cutoff saws
• Can cause hand and body injuries
in several ways:
1. while the blade coasts or idles
2. when operators remove a sawed
section or scrap
3. when operators measure boards or
place them in position for the cut
4. if saw bounces forward from
retracted position
5. pulling the saw against their hands
in the cutting path
Saws (Cont.)
• Overhead swing saws and straight-line pull cutoff saws
• Guarding
• Must have a guard hood that extends 2 in. in front of the blade.
• Provide a counterweight to return the saw when not cutting without
rebounding.
• Install a limit chain or magnetic latches
• Easily accessible START/STOP buttons
Saws (Cont.)
• Overhead swing saws and straight-line pull cutoff saws—
operation
• If the saw is pulled by a handle, the handle should be attached to
either the right or the left of the saw rather than in line with it.
• The operator should stand to the handle side and pull the saw with
the hand near it.
• At the completion of each cut, the operator should put the saw back
to the idling position and make sure all bounce back has stopped
before putting his/her hand on the table.
Saws (Cont.)
• Radial saws
• When cross cutting, radial saws cut downward and pull the wood
away from the operator and against a fence.
• Always guard the upper half of the saw, including the arbor end.
• The lower guard should auto-adjust to the stock thickness and
remain in contact with the stock being cut for the full working range.
• The saw table should be large enough to
cover the blade in any position (miter, bevel,
or rip).
• Radial saw injuries are typically caused by
cuts to the arms and hands from the blade,
flying wood chips, and handling materials.
Saws (Cont.)
• Radial saws—ripping
• Before ripping: position the nose of the guard, spreader and antikickback devices.
• When ripping, rotate the radial saw’s head 90o so the blade is
parallel to the fence and is clamped in position.
• Feed the stock against the direction of rotation of the revolving
blade.
• CAUTION: Operators should always follow the proper direction of
blade rotation.
• Feeding from the wrong side tends to grab the material away from the
operator and throw it toward the end of the guard.
Saws (Cont.)
Saws (Cont.)
Saws (Cont.)
In-ripping >
Out-ripping >
Saws (Cont.)
• Radial saws—ripping (cont.)
• Two possibilities of severe injury arise from feeding from the
wrong side.
• Hands can be drawn into the saw.
• Flying stock
• Operators should exercise special care when ripping material
with thin, lightweight, hard, or slippery surfaces because of the
reduced efficiency of anti-kickback devices.
• When ripping, the operator should wear an anti-kickback apron.
Saws (Cont.)
• Radial saws—crosscutting
• Radial saws used for crosscutting are pulled across the cutting
area by means of a handle located to one side of the blade.
• Operators should stand on the handle’s side and not be in line with
the blade.
• Never remove short pieces from the table until the saw has been
returned.
• Workers should develop the habit of holding their arms straight
from their shoulder to their waist because of the blades direction of
rotation and the feed direction.
Saws (Cont.)
• Power-feed ripsaws
• The working end of the saw should have 3 ft of clearance.
• Operators should adjust feed rolls to the thickness of the stock
being ripped.
• Insufficient pressure on the stock can contribute to kickbacks.
Saws (Cont.)
• Band saws
• Injuries from band saws are less frequent and severe than other
saws.
• Push stick to control the work piece when it’s close to the blade.
• Ensure the working area is well lit.
• Install adjustable guard when possible.
• Install a brake for band saws that run for a long time after the
power is shut off.
• When working small pieces, use a special jig or fixture.
Saws (Cont.)
Woodworking Equipment
• All woodworking equipment poses safety hazards for
those operating it or working around or near the
equipment.
• Workers must be trained in safe work practices and in
emergency first aid and other procedures to prevent or
minimize injuries.
• Common equipment includes:
• jointers-planers
• shapers
• power-feed planers
• sanders
• lathes and shapers
Woodworking Equipment (Cont.)
• Joint-planers
• Second only to circular saws, they are the most dangerous
woodworking machines.
• Most injuries are caused when the hands and fingers of operators come
in contact with these machines’ knives when working with short lengths
of stock.
• The openings between the table and the head should be just large
enough to clear the knife.
• Use hold-down push blocks whenever the operator joints wood
narrower than 3 in.
• Operators should never place their hands over the front or back
edges.
Woodworking Equipment (Cont.)
Woodworking Equipment (Cont.)
Woodworking Equipment (Cont.)
Woodworking Equipment (Cont.)
• Shapers
• The greatest number of injury incidents occurs when shaping
narrow stock.
• Use hold-down push block or jigs in these instances.
• Always feed against the direction of the rotation cutter.
• Eliminate the danger from broken or thrown knives by using solid
cutters that fit over the spindle.
• Cutters are always safer than knives.
• Use applicable guards when possible.
• Adjust the cutting-head guard for minimum head exposure.
Woodworking Equipment (Cont.)
Woodworking Equipment (Cont.)
• Power-feed planers
• Operators can reduce planer vibration by anchoring the planer on a
solid foundation and by insulating it from the foundation.
• Due to the noise they generate, power-feed planers should be used in a
separate room or soundproof enclosure.
• Completely enclose cutter heads in solid metal guards.
• Never adjust feed rolls, cutter heads, and cylinders during
operation. Use proper lockout methods.
• Ensure that operators and other work stations are not positioned on
the backside of power-feed planer operations.
• The danger of kickbacks cannot be entirely overcome by mechanical
means.
Woodworking Equipment (Cont.)
• Sanders
• Enclose drum, disk, or belt-sanding operations with dust exhaust
hoods.
• Use applicable guard feed rolls at each running nip point.
• All hand-feed sanders should have a work rest and (1) be properly
adjusted to provide minimum clearance between the belt and rest
and (2) to secure support for the work.
• Operators should inspect abrasive belts before using them and
replace those found to be torn, frayed, or excessively worn.
Woodworking Equipment (Cont.)
• Lathes and shapers
• Supervisors or operators should ensure that the rotating heads of
lathes, whether running or not, are covered as completely as
possible by hoods or shields.
• Use hinge hoods that can be thrown back when adjustments are
needed.
• Management should select and train lathe operators with care.
• Operators must give constant attention to stock being turned in
order to discard any material likely to break.
• Operators must wear proper PPE: safety goggles and face shield.
Summary
• All electrically driven machines should be adequately
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•
grounded, have a cutoff switch, and have some means of
rendering controls inoperative.
Employees using woodworking machines should read the
operator’s manual prior to working with new equipment.
Employees must follow good housekeeping procedures
around their work area.
Management should guard against hearing loss, airborne
dusts and contamination, explosion, and fire hazards.
Management can minimize hazards posed by saws by
training operators, ensuring all machines are guarded,
and making sure operators follow all safety procedures.
THE END