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Accident Prevention Manual

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Title: Chapter 21 Woodworking Machinery Author: Grant Weller Last modified by: Deborah Meyer Created Date: 3/11/2013 2:51:22 PM Document presentation format – PowerPoint PPT presentation

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Title: Accident Prevention Manual


1
  • 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
2
CHAPTER 21
  • WOODWORKING MACHINERY

3
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.

4
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.

5
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.

6
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.

7
General Safety Principles (Cont.)
  • Example of devices stopping restart

8
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.

9
General Safety Principles (Cont.)
10
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.

11
General Safety Principles (Cont.)
  • Guards (cont.)
  • Point-of-Operation Guards must
  • be moveable to accommodate the wood.
  • balanced so as not to impede the operations.
  • strong enough to provide protection to the
    operator.
  • Whenever possible, completely cover blades and
    cutting edges at the point of operation.

12
General Safety Principles (Cont.)
  • Work areas
  • Provide ample work space around each machine.
  • See Table 21A 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.

13
General Safety Principles (Cont.)
14
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.

15
General Safety Principles (Cont.)
  • Materials handling
  • Facility layout should encourage an even flow of
    materials and keep backtracking and crisscrossing
    to a minimum.
  • Operators shouldnt 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.

16
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
    manufacturers recommendations and requirements
    and flow patterns of the workplace.

17
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.

18
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.

19
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.

20
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.

21
Saws
  • All saws pose potential hazards for operators.
    EHS professionals can minimize these hazards by
  • providing training for operators.
  • ensuring that all machinery is properly guarded.
  • making sure that all ANSI, NFPA, and government
    regulations are followed.

22
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.

23
Saws (Cont.)
  • Circular Saws
  • 21-5 and 21-6

24
Saws (Cont.)
  • Circular sawskickback 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 blades guards, spreaders, and anti-kickback
    pawls in place and operating properly.

25
Saws (Cont.)
  • Circular Sawskickbacks and ripping (cont.)
  • Prevention methods
  • Cut only material that is seasoned, dry, and flat
    and that has a straight 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.

26
Saws (Cont.)
  • Ripping
  • procedure

27
Saws (Cont.)
  • Circular sawsguards
  • 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.

28
Saws (Cont.)
29
Saws (Cont.)
30
Saws (Cont.)
  • Circular sawsrabbeting 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.

31
Saws (Cont.)
32
Saws (Cont.)
  • Circular Sawsproper 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 doesnt 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 mandrels speed.
  • Use the right saw for the right job.
  • Take into consideration blade height.
  • Operators should stop a circular table saw before
    leaving it.

33
Saws (Cont.)
34
Saws (Cont.)
  • Circular Sawsselection 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 saws 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

35
Saws (Cont.)
36
Saws (Cont.)
37
Saws (Cont.)
38
Saws (Cont.)
  • Overhead swing saws and straight-line pull cutoff
    saws
  • Can cause hand and body injuries in several ways
  • while the blade coasts or idles
  • when operators remove a sawed section or scrap
  • when operators measure boards or place them in
    position for the cut
  • if saw bounces forward from retracted position
  • pulling the saw against their hands in the
    cutting path

39
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

40
Saws (Cont.)
  • Overhead swing saws and straight-line pull cutoff
    sawsoperation
  • 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.

41
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.

42
Saws (Cont.)
  • Radial sawsripping
  • Before ripping position the nose of the guard,
    spreader and anti-kickback devices.
  • When ripping, rotate the radial saws 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.

43
Saws (Cont.)
44
Saws (Cont.)
45
Saws (Cont.)
  • In-ripping gt
  • Out-ripping gt

46
Saws (Cont.)
  • Radial sawsripping (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.

47
Saws (Cont.)
  • Radial sawscrosscutting
  • 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 handles 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.

48
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.

49
Saws (Cont.)
  • Band saws
  • Injuries from band saws are less frequent and
    severe than other saws.
  • Push stick to control the work piece when its
    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.

50
Saws (Cont.)
51
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

52
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.

53
Woodworking Equipment (Cont.)
54
Woodworking Equipment (Cont.)
55
Woodworking Equipment (Cont.)
56
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.

57
Woodworking Equipment (Cont.)
58
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.

59
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.

60
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.

61
Summary
  • All electrically driven machines should be
    adequately grounded, have a cutoff switch, and
    have some means of rendering controls
    inoperative.
  • Employees using woodworking machines should read
    the operators 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.

62
  • THE END
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