(a)
Machine construction general.
(1)
Each machine shall be so constructed as to be free from sensible
vibration when the largest size tool is mounted and run idle
at full speed.
(2) Arbors and mandrels shall be constructed so as to have firm
and secure bearing and be free from play.
(3) [Reserved]
(4) Any automatic cutoff saw that strokes continuously without
the operator being able to control each stroke shall not be
used.
(5) Saw frames or tables shall be constructed with lugs cast
on the frame or with an equivalent means to limit the size of
the saw blade that can be mounted, so as to avoid overspeed
caused by mounting a saw larger than intended.
(6) Circular saw fences shall be so constructed that they can
be firmly secured to the table or table assembly without changing
their alignment with the saw. For saws with tilting tables or
tilting arbors the fence shall be so constructed that it will
remain in a line parallel with the saw, regardless of the angle
of the saw with the table.
(7) Circular saw gages shall be so constructed as to slide in
grooves or tracks that are accurately machined, to insure exact
alignment with the saw for all positions of the guide.
(8) Hinged saw tables shall be so constructed that the table
can be firmly secured in any position and in true alignment
with the saw.
(9) All belts, pulleys, gears, shafts, and moving parts shall
be guarded in accordance with the specific requirements of 1910.219.
(10) It is recommended that each power-driven woodworking machine
be provided with a disconnect switch that can be locked in the
off position.
(11) The frames and all exposed, noncurrent-carrying metal parts
of portable electric woodworking machinery operated at more
than 90 volts to ground shall be grounded and other portable
motors driving electric tools which are held in the hand while
being operated shall be grounded if they operate at more than
90 volts to ground. The ground shall be provided through use
of a separate ground wire and polarized plug and receptacle.
(12) For all circular saws where conditions are such that there
is a possibility of contact with the portion of the saw either
beneath or behind the table, that portion of the saw shall be
covered with an exhaust hood, or, if no exhaust system is required,
with a guard that shall be so arranged as to prevent accidental
contact with the saw.
(13) Revolving double arbor saws shall be fully guarded in accordance
with all the requirements for circular crosscut saws or with
all the requirements for circular ripsaws, according to the
kind of saws mounted on the arbors.
(14) No saw, cutter head, or tool collar shall be placed or
mounted on a machine arbor unless the tool has been accurately
machined to size and shape to fit the arbor.
(15) Combs (featherboards) or suitable jigs shall be provided
at the workplace for use when a standard guard cannot be used,
as in dadoing, grooving, jointing, moulding, and rabbeting.
(b)
Machine controls and equipment.
(1) A mechanical or electrical power control shall be provided
on each machine to make it possible for the operator to cut
off the power from each machine without leaving his position
at the point of operation.
(2) On machines driven by belts and shafting, a locking-type
belt shifter or an equivalent positive device shall be used.
(3) On applications where injury to the operator might result
if motors were to restart after power failures, provision shall
be made to prevent machines from automatically restarting upon
restoration of power.
(4) Power controls and operating controls should be located
within easy reach of the operator while he is at his regular
work location, making it unnecessary for him to reach over the
cutter to make adjustments. This does not apply to constant
pressure controls used only for setup purposes.
(5) On each machine operated by electric motors, positive means
shall be provided for rendering such controls or devices inoperative
while repairs or adjustments are being made to the machines
they control.
(6) Each operating treadle shall be protected against unexpected
or accidental tripping.
(7) Feeder attachments shall have the feed rolls or other moving
parts so covered or guarded as to protect the operator from
hazardous points.
(c) Hand-fed ripsaws.
(1)
Each circular hand-fed ripsaw shall be guarded by a hood which
shall completely enclose that portion of the saw above the table
and that portion of the saw above the material being cut. The
hood and mounting shall be arranged so that the hood will automatically
adjust itself to the thickness of and remain in contact with
the material being cut but it shall not offer any considerable
resistance to insertion of material to saw or to passage of
the material being sawed. The hood shall be made of adequate
strength to resist blows and strains incidental to reasonable
operation, adjusting, and handling, and shall be so designed
as to protect the operator from flying splinters and broken
saw teeth. It shall be made of material that is soft enough
so that it will be unlikely to cause tooth breakage. The hood
shall be so mounted as to insure that its operation will be
positive, reliable, and in true alignment with the saw; and
the mounting shall be adequate in strength to resist any reasonable
side thrust or other force tending to throw it out of line.
(2) Each
hand-fed circular ripsaw shall be furnished with a spreader
to prevent material from squeezing the saw or being thrown back
on the operator. The spreader shall be made of hard tempered
steel, or its equivalent, and shall be thinner than the saw
kerf. It shall be of sufficient width to provide adequate stiffness
or rigidity to resist any reasonable side thrust or blow tending
to bend or throw it out of position. The spreader shall be attached
so that it will remain in true alignment with the saw even when
either the saw or table is tilted. The provision of a spreader
in connection with grooving, dadoing, or rabbeting is not required.
On the completion of such operations, the spreader shall be
immediately replaced.
(3) Each
hand-fed circular ripsaw shall be provided with nonkickback
fingers or dogs so located as to oppose the thrust or tendency
of the saw to pick up the material or to throw it back toward
the operator. They shall be designed to provide adequate holding
power for all the thicknesses of materials being cut.
(d)
Hand-fed crosscut table saws.
(1) Each circular crosscut table saw shall be guarded by a hood
which shall meet all the requirements of paragraph (c)(1) of
this section for hoods for circular ripsaws.
(e) Circular resaws.
(1)
Each circular resaw shall be guarded by a hood or shield of
metal above the saw. This hood or shield shall be so designed
as to guard against danger from flying splinters or broken saw
teeth.
(2) Each
circular resaw (other than self-feed saws with a roller or wheel
at back of the saw) shall be provided with a spreader fastened
securely behind the saw. The spreader shall be slightly thinner
than the saw kerf and slightly thicker than the saw disk.
(f) Self-feed circular saws.
(1) Feed rolls and saws shall be protected by a hood or guard
to prevent the hands of the operator from coming in contact
with the in-running rolls at any point. The guard shall be constructed
of heavy material, preferably metal, and the bottom of the guard
shall come down to within three-eighths inch of the plane formed
by the bottom or working surfaces of the feed rolls. This distance
(three-eighths inch) may be increased to three-fourths inch,
provided the lead edge of the hood is extended to be not less
than 5 1/2 inches in front of the nip point between the front
roll and the work.
(2) Each self-feed circular ripsaw shall be provided with sectional
non-kickback fingers for the full width of the feed rolls. They
shall be located in front of the saw and so arranged as to be
in continual contact with the wood being fed.
(g) Swing cutoff saws.
The requirements of this paragraph are also applicable to sliding
cutoff saws mounted above the table.
(1) Each
swing cutoff saw shall be provided with a hood that will completely
enclose the upper half of the saw, the arbor end, and the point
of operation at all positions of the saw. The hood shall be
constructed in such a manner and of such material that it will
protect the operator from flying splinters and broken saw teeth.
Its hood shall be so designed that it will automatically cover
the lower portion of the blade, so that when the saw is returned
to the back of the table the hood will rise on top of the fence,
and when the saw is moved forward the hood will drop on top
of and remain in contact with the table or material being cut.
(2) Each
swing cutoff saw shall be provided with an effective device
to return the saw automatically to the back of the table when
released at any point of its travel. Such a device shall not
depend for its proper functioning upon any rope, cord, or spring.
If there is a counterweight, the bolts supporting the bar and
counterweight shall be provided with cotter pins; and the counterweight
shall be prevented from dropping by either a bolt passing through
both the bar and counterweight, or a bolt put through the extreme
end of the bar, or, where the counterweight does not encircle
the bar, a safety chain attached to it.
(3) Limit
chains or other equally effective devices shall be provided
to prevent the saw from swinging beyond the front or back edges
of the table, or beyond a forward position where the gullets
of the lowest saw teeth will rise above the table top.
(4) Inverted
swing cutoff saws shall be provided with a hood that will cover
the part of the saw that protrudes above the top of the table
or above the material being cut. It shall automatically adjust
itself to the thickness of and remain in contact with the material
being cut.
(h) Radial saws.
(1) The upper hood shall completely enclose the upper portion
of the blade down to a point that will include the end of the
saw arbor. The upper hood shall be constructed in such a manner
and of such material that it will protect the operator from
flying splinters, broken saw teeth, etc., and will deflect sawdust
away from the operator. The sides of the lower exposed portion
of the blade shall be guarded to the full diameter of the blade
by a device that will automatically adjust itself to the thickness
of the stock and remain in contact with stock being cut to give
maximum protection possible for the operation being performed.
(2) Each
radial saw used for ripping shall be provided with nonkickback
fingers or dogs located on both sides of the saw so as to oppose
the thrust or tendency of the saw to pick up the material or
to throw it back toward the operator. They shall be designed
to provide adequate holding power for all the thicknesses of
material being cut.
(3) An
adjustable stop shall be provided to prevent the forward travel
of the blade beyond the position necessary to complete the cut
in repetitive operations.
(4) Installation
shall be in such a manner that the front end of the unit will
be slightly higher than the rear, so as to cause the cutting
head to return gently to the starting position when released
by the operator.
(5) Ripping
and ploughing shall be against the direction in which the saw
turns. The direction of the saw rotation shall be conspicuously
marked on the hood. In addition, a permanent label not less
than 1 1/2 inches by 3/4 inch shall be affixed to the rear of
the guard at approximately the level of the arbor, reading as
follows: "Danger: Do Not Rip or Plough From This End".
(i) Bandsaws and band resaws.
(1) All portions of the saw blade shall be enclosed or guarded,
except for the working portion of the blade between the bottom
of the guide rolls and the table. Bandsaw wheels shall be fully
encased. The outside periphery of the enclosure shall be solid.
The front and back of the band wheels shall be either enclosed
by solid material or by wire mesh or perforated metal. Such
mesh or perforated metal shall be not less than 0.037 inch (U.S.
Gage No. 20), and the openings shall be not greater than three-eighths
inch. Solid material used for this purpose shall be of an equivalent
strength and firmness. The guard for the portion of the blade
between the sliding guide and the upper-saw-wheel guard shall
protect the saw blade at the front and outer side. This portion
of the guard shall be self-adjusting to raise and lower with
the guide. The upper-wheel guard shall be made to conform to
the travel of the saw on the wheel.
(2) Each
bandsaw machine shall be provided with a tension control device
to indicate a proper tension for the standard saws used on the
machine, in order to assist in the elimination of saw breakage
due to improper tension.
(3) Feed
rolls of band resaws shall be protected with a suitable guard
to prevent the hands of the operator from coming in contact
with the in-running rolls at any point. The guard shall be constructed
of heavy material, preferably metal, and the edge of the guard
shall come to within three-eighths inch of the plane formed
by the inside face of the feed roll in contact with the stock
being cut.
(j) Jointers.
(1) Each hand-fed planer and jointer with horizontal head shall
be equipped with a cylindrical cutting head, the knife projection
of which shall not exceed one-eighth inch beyond the cylindrical
body of the head.
(2) The
opening in the table shall be kept as small as possible. The
clearance between the edge of the rear table and the cutter
head shall be not more than one-eighth inch. The table throat
opening shall be not more than 2 1/2 inches when tables are
set or aligned with each other for zero cut.
(3) Each
hand-fed jointer with a horizontal cutting head shall have an
automatic guard which will cover all the section of the head
on the working side of the fence or gage. The guard shall effectively
keep the operator's hand from coming in contact with the revolving
knives. The guard shall automatically adjust itself to cover
the unused portion of the head and shall remain in contact with
the material at all times.
(4) Each
hand-fed jointer with horizontal cutting head shall have a guard
which will cover the section of the head back of the gage or
fence.
(5) Each
wood jointer with vertical head shall have either an exhaust
hood or other guard so arranged as to enclose completely the
revolving head, except for a slot of such width as may be necessary
and convenient for the application of the material to be jointed.
(k) Tenoning machines.
(1) Feed chains and sprockets of all double end tenoning machines
shall be completely enclosed, except for that portion of chain
used for conveying the stock.
(2) At the rear ends of frames over which feed conveyors run,
sprockets and chains shall be guarded at the sides by plates
projecting beyond the periphery of sprockets and the ends of
lugs.
(3) Each tenoning machine shall have all cutting heads, and
saws if used, covered by metal guards. These guards shall cover
at least the unused part of the periphery of the cutting head.
If such a guard is constructed of sheet metal, the material
used shall be not less than one-sixteenth inch in thickness,
and if cast iron is used, it shall be not less than three-sixteenths
inch in thickness.
(4) Where an exhaust system is used, the guard shall form part
or all of the exhaust hood and shall be constructed of metal
of a thickness not less than that specified in subparagraph
(3) of this paragraph.
(l) Boring and mortising machines.
(1) Safety-bit
chucks with no projecting set screws shall be used.
(2) Boring
bits should be provided with a guard that will enclose all portions
of the bit and chuck above the material being worked.
(3) The
top of the cutting chain and driving mechanism shall be enclosed.
(4) If
there is a counterweight, one of the following or equivalent
means shall be used to prevent its dropping:
(i) It shall be bolted to the bar by means of a bolt passing
through both bar and counterweight;
(ii)
A bolt shall be put through the extreme end of the bar;
(iii) Where
the counterweight does not encircle the bar, a safety chain
shall be attached to it;
(iv) Other
types of counterweights shall be suspended by chain or wire
rope and shall travel in a pipe or other suitable enclosure
wherever they might fall and cause injury.
(5) Universal joints on spindles of boring machines shall be
completely enclosed in such a way as to prevent accidental contact
by the operator.
(6) Each operating treadle shall be covered by an inverted U-shaped
metal guard, fastened to the floor, and of adequate size to
prevent accidental tripping.
(m) Wood shapers and similar equipment.
(1)
The cutting heads of each wood shaper, hand-fed panel raiser,
or other similar machine not automatically fed, shall be enclosed
with a cage or adjustable guard so designed as to keep the operator's
hand away from the cutting edge. The diameter of circular shaper
guards shall be not less than the greatest diameter of the cutter.
In no case shall a warning device of leather or other material
attached to the spindle be acceptable.
(2) [Reserved]
(3) All double-spindle shapers shall be provided with a spindle
starting and stopping device for each spindle.
(n) Planing, molding, sticking, and matching machines.
(1) Each planing, molding, sticking, and matching machine shall
have all cutting heads, and saws if used, covered by a metal
guard. If such guard is constructed of sheet metal, the material
used shall be not less than 1/16 inch in thickness, and if cast
iron is used, it shall be not less than three-sixteenths inch
in thickness.
(2) Where an exhaust system is used, the guards shall form part
or all of the exhaust hood and shall be constructed of metal
of a thickness not less than that specified in paragraph (h)(1)
of this section.
(3) Feed rolls shall be guarded by a hood or suitable guard
to prevent the hands of the operator from coming in contact
with the in-running rolls at any point. The guard shall be fastened
to the frame carrying the rolls so as to remain in adjustment
for any thickness of stock.
(4) Surfacers or planers used in thicknessing multiple pieces
of material simultaneously shall be provided with sectional
infeed rolls having sufficient yield in the construction of
the sections to provide feeding contact pressure on the stock,
over the permissible range of variation in stock thickness specified
or for which the machine is designed. In lieu of such yielding
sectional rolls, suitable section kickback finger devices shall
be provided at the infeed end.
(o) Profile and swing-head lathes and wood heel turning
machine.
(1) Each profile and swing-head lathe shall have all cutting
heads covered by a metal guard. If such a guard is constructed
of sheet metal, the material used shall be not less than one-sixteenth
inch in thickness; and if cast iron is used, it shall not be
less than three-sixteenths inch in thickness.
(2) Cutting heads on wood-turning lathes, whether rotating or
not, shall be covered as completely as possible by hoods or
shields.
(3) Shoe last and spoke lathes, doweling machines, wood heel
turning machines, and other automatic wood-turning lathes of
the rotating knife type shall be equipped with hoods enclosing
the cutter blades completely except at the contact points while
the stock is being cut.
(4) Lathes used for turning long pieces of wood stock held only
between the two centers shall be equipped with long curved guards
extending over the tops of the lathes in order to prevent the
work pieces from being thrown out of the machines if they should
become loose.
(5) Where an exhaust system is used, the guard shall form part
or all of the exhaust hood and shall be constructed of metal
of a thickness not less than that specified in subparagraph
(1) of this paragraph.
(p) Sanding machines.
(1)
Feed rolls of self-feed sanding machines shall be protected
with a semicylindrical guard to prevent the hands of the operator
from coming in contact with the in-running rolls at any point.
The guard shall be constructed of heavy material, preferably
metal, and firmly secured to the frame carrying the rolls so
as to remain in adjustment for any thickness of stock. The bottom
of the guard should come down to within three-eighths inch of
a plane formed by the bottom or contact face of the feed roll
where it touches the stock.
(2) Each drum sanding machine shall have an exhaust hood, or
other guard if no exhaust system is required, so arranged as
to enclose the revolving drum, except for that portion of the
drum above the table, if a table is used, which may be necessary
and convenient for the application of the material to be finished.
(3) Each disk sanding machine shall have the exhaust hood, or
other guard if no exhaust system is required, so arranged as
to enclose the revolving disk, except for that portion of the
disk above the table, if a table is used, which may be necessary
for the application of the material to be finished.
(4) Belt sanding machines shall be provided with guards at each
nip point where the sanding belt runs on to a pulley. These
guards shall effectively prevent the hands or fingers of the
operator from coming in contact with the nip points. The unused
run of the sanding belt shall be guarded against accidental
contact.
(q) Veneer cutters and wringers.
(1)
Veneer slicer knives shall be guarded to prevent accidental
contact with knife edge, at both front and rear.
(2) Veneer clippers shall have automatic feed or shall be provided
with a guard which will make it impossible to place a finger
or fingers under the knife while feeding or removing the stock.
(3) Sprockets on chain or slat-belt conveyors shall be enclosed.
(4) Where practicable, hand and footpower guillotine veneer
cutters shall be provided with rods or plates or other satisfactory
means, so arranged on the feeding side that the hands cannot
reach the cutting edge of the knife while feeding or holding
the stock in place.
(5) Power-driven guillotine veneer cutters, except continuous
feed trimmers, shall be equipped with:
(i) Starting devices which require the simultaneous action
of both hands to start the cutting motion and of at least
one hand on a control during the complete stroke of the knife;
or
(ii) An automatic guard which will remove the hands of the
operator from the danger zone at every descent of the blade,
used in conjunction with one-hand starting devices which require
two distinct movements of the device to start the cutting
motion, and so designed as to return positively to the nonstarting
position after each complete cycle of the knife.
(6)
Where two or more workers are employed at the same time on the
same power-driven guillotine veneer cutter equipped with two-hand
control, the device shall be so arranged that each worker shall
be required to use both hands simultaneously on the controls
to start the cutting motion, and at least one hand on a control
to complete the cut.
(7) Power-driven guillotine veneer cutters, other than continuous
trimmers, shall be provided, in addition to the brake or other
stopping mechanism, with an emergency device which will prevent
the machine from operating in the event of failure of the brake
when the starting mechanism is in the nonstarting position.
(r) Miscellaneous woodworking machines.
(1) The feed rolls of roll type glue spreaders shall be guarded
by a semicylindrical guard. The bottom of the guard shall come
to within three-eighths inch of a plane formed by bottom or
contact face of the feed roll where it touches the stock.
(2) Drag saws shall be so located as to give at least a 4-foot
clearance for passage when the saw is at the extreme end of
the stroke; or if such clearance is not obtainable, the saw
and its driving mechanism shall be provided with a standard
enclosure.
(3) For combination or universal woodworking machines each point
of operation of any tool shall be guarded as required for such
a tool in a separate machine.
(4) The mention of specific machines in paragraphs (a) thru
(q) and this paragraph (r) of this section, inclusive, is not
intended to exclude other woodworking machines from the requirement
that suitable guards and exhaust hoods be provided to reduce
to a minimum the hazard due to the point of operation of such
machines.
(s) Inspection and maintenance of woodworking machinery.
(1) Dull,
badly set, improperly filed, or improperly tensioned saws shall
be immediately removed from service, before they begin to cause
the material to stick, jam, or kick back when it is fed to the
saw at normal speed. Saws to which gum has adhered on the sides
shall be immediately cleaned.
(2) All
knives and cutting heads of woodworking machines shall be kept
sharp, properly adjusted, and firmly secured. Where two or more
knives are used in one head, they shall be properly balanced.
(3) Bearings
shall be kept free from lost motion and shall be well lubricated.
(4) Arbors
of all circular saws shall be free from play.
(5) Sharpening
or tensioning of saw blades or cutters shall be done only by
persons of demonstrated skill in this kind of work.
(6) Emphasis
is placed upon the importance of maintaining cleanliness around
woodworking machinery, particularly as regards the effective
functioning of guards and the prevention of fire hazards in
switch enclosures, bearings, and motors.
(7) All
cracked saws shall be removed from service.
(8) The
practice of inserting wedges between the saw disk and the collar
to form what is commonly known as a "wobble saw" shall
not be permitted.
(9) Push
sticks or push blocks shall be provided at the work place in
the several sizes and types suitable for the work to be done.
(10) [Reserved]
(11) [Reserved]
(12) The
knife blade of jointers shall be so installed and adjusted that
it does not protrude more than one-eighth inch beyond the cylindrical
body of the head. Push sticks or push blocks shall be provided
at the work place in the several sizes and types suitable for
the work to be done.
(13) Whenever
veneer slicers or rotary veneer-cutting machines have been shutdown
for the purpose of inserting logs or to make adjustments, operators
shall make sure that machine is clear and other workmen are
not in a hazardous position before starting the machine.
(14) Operators
shall not ride the carriage of a veneer slicer.