Subpart A General

Subpart B Adoption and Extension of Established Federal Standards

Subpart C Adoption and Extension of Established Federal Standards

Subpart D Walking-Working Surfaces

Subpart E Means of Egress

Subpart F Powered Platforms, Manlifts, and Vehicle-Mounted Work Platforms

Subpart G Occupational Health and Environmental Control

Subpart H Hazardous Materials

Subpart I Personal Protective Equipment

Subpart J General Environmental Controls

Subpart K Medical and First Aid

Subpart L Fire Protection

Subpart M Compressed Gas and Compressed Air Equipment

Subpart N Materials Handling and Storage

Subpart O Machinery and Machine Guarding

Subpart P Hand and Portable Powered Tools and Other Hand-Held Equipment

Subpart Q Welding, Cutting, and Brazing

Subpart R Special Industries

Subpart S Electrical

Subpart T Commercial Diving Operations

Subpart U [Reserved]

Subpart V [Reserved]

Subpart W Program Standard

Subpart X [Reserved]

Subpart Y [Reserved]

Subpart Z Toxic and Hazardous Substances

Authority: 29 U.S.C. 653, 655, 657; Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 5-2002 (67 FR 65008), or 1-2012 (77 FR 3912), as applicable; 20 CFR part 1911. Sections 1910.217 and 1910.219 also issued under 5 U.S.C. 553.

[61 FR 9227, March 7, 1996; 69 FR 31881, June 8, 2004; 76 FR 80739, Dec. 27, 2011; 77 FR 46949, Aug. 7, 2012; 78 FR 69549, Nov. 20, 2013]
As used in 1910.213 and 1910.214 unless the context clearly requires otherwise, the following woodworking machinery terms shall have the meaning prescribed in this paragraph.
Point of operations means that point at which cutting, shaping, boring, or forming is accomplished upon the stock.
Push stick means a narrow strip of wood or other soft material with a notch cut into one end and which is used to push short pieces of material through saws.
Block means a short block of wood, provided with a handle similar to that of a plane and a shoulder at the rear end, which is used for pushing short stock over revolving cutters.
As used in 1910.215 unless the context clearly requires otherwise, the following abrasive wheel machinery terms shall have the meanings prescribed in this paragraph.
Type 1 straight wheels means wheels having diameter, thickness, and hole size dimensions, and they should be used only on the periphery. Type 1 wheels shall be mounted between flanges.

Limitation: Hole dimension (H) should not be greater than two-thirds of wheel diameter dimension (D) for precision, cylindrical, centerless, or surface grinding applications. Maximum hole size for all other applications should not exceed one-half wheel diameter.
FIGURE NO. O-1. - TYPE 1 STRAIGHT WHEELS
Peripheral grinding wheel having a diameter, thickness and hole.
Type 2 cylinder wheels means wheels having diameter, wheel thickness, and rim thickness dimensions. Grinding is performed on the rim face only, dimension W. Cylinder wheels may be plain, plate mounted, inserted nut, or of the projecting stud type.

Limitation: Rim height, T dimension, is generally equal to or greater than rim thickness, W dimension.
FIGURE NO. O-2. - TYPE 2 CYLINDER WHEELS
Side grinding wheel having a diameter, thickness and wall - wheel is mounted on the diameter.
Type 6 straight cup wheels means wheels having diameter, thickness, hole size, rim thickness, and back thickness dimensions. Grinding is always performed on rim face, W dimension.

LIMITATION: Minimum back thickness, E dimension, should not be less than one-fourth T dimension. In addition, when unthreaded hole wheels are specified, the inside flat, K dimension, must be large enough to accommodate a suitable flange.

FIGURE NO. O-3. - TYPE 6 STRAIGHT CUP WHEELS



Side grinding wheel having a diameter, thickness and hole with one side straight or flat and the opposite side recessed. This type, however, differs from Type 5 in that the grinding is performed on the wall of the abrasive created by the difference between the diameter of the recess and the outside diameter of the wheel. Therefore, the wall dimension "W" takes precedence over the diameter of the recess as an essential intermediate dimension to describe this shape type.
Type 11 flaring cup wheels mean wheels having double diameter dimensions D and J, and in addition have thickness, hole size, rim and back thickness dimensions. Grinding is always performed on rim face, W dimension. Type 11 wheels are subject to all limitations of use and mounting listed for type 6 straight sided cup wheels definition.

LIMITATION: Minimum back thickness, E dimension, should not be less than one-fourth T dimension. In addition when unthreaded hole wheels are specified the inside flat, K dimension, shall be large enough to accommodate a suitable flange.

FIGURE NO. O-4. - TYPE 11 FLARING CUP WHEELS



Side grinding wheel having a wall flared or tapered outward from the back. Wall thickness at the back is normally greater than at the grinding face (W).
Modified types 6 and 11 wheels (terrazzo) mean some type 6 and 11 cup wheels used in the terrazzo trade having tapered K dimensions to match a special tapered flange furnished by the machine builder.

LIMITATION: These wheels shall be mounted only with a special tapered flange.

FIGURE NO. O-5



Typical examples of modified types 6 and 11 wheels (terrazzo) showing tapered K dimensions.
Types 27 and 28 depressed center wheels mean wheels having diameter, thickness, and hole size dimensions. Both types are reinforced, organic bonded wheels having offset hubs which permit side and peripheral grinding operations without interference with the mounting. Type 27 wheels are manufactured with flat grinding rims permitting notching and cutting operations. Type 28 wheels have saucer shaped grinding rims.
Special supporting, back adapter and inside flange nuts are required for the proper mounting of these types of wheels subject to limitations of 1910.215(c)(4)(i) and (ii).
Mounts which are affixed to the wheel by the manufacturer may not require an inside nut and shall not be reused.
Type 27A depressed center, cutting-off wheels mean wheels having diameter, thickness, and hole size dimensions. They are reinforced, organic bonded, offset hub type wheels, usually 16 inches diameter and larger, specially designed for use on cutting-off machines where mounting nut or outer flange interference cannot be tolerated.

LIMITATIONS: See 1910.215(c)(1).
Surface feet per minute (s.f.p.m.) means the distance in feet any one abrasive grain on the peripheral surface of a grinding wheel travels in 1 minute.
Surface Feet Per Minute = 3.1416 X diameter in inches X r.p.m.
divided by 12 or .262 X diameter in
inches X r.p.m.

Examples:

a) 24-inch diameter wheel, 1,000 revolutions per minute. Surface Feet per minute .262 X 24 X 1,000 = 6,288 s.f.p.m.

b) 12-inch diameter wheel, 1,000 revolutions per minute. Surface Feet per minute .262 X 12 X 1,000 = 3,144 s.f.p.m.
Flanges means collars, discs or plates between which wheels are mounted and are referred to as adaptor, sleeve, or back up type. See paragraph (c) of 1910.215 for full description.
Snagging means grinding which removes relatively large amounts of material without regard to close tolerances or surface finish requirements.
Off-hand grinding means the grinding of any material or part which is held in the operator's hand.
Safety guard means an enclosure designed to restrain the pieces of the grinding wheel and furnish all possible protection in the event that the wheel is broken in operation. See paragraph (b) of 1910.215.
Cutting off wheels means wheels having diameter thickness and hole size dimensions and are subject to all limitations of mounting and use listed for type 1 wheels, the definition in subparagraph (1) of this paragraph and paragraph (d) of 1910.215. They may be steel centered, diamond abrasive or organic bonded abrasive of the plain or reinforced type.
Cutting off wheels are recommended only for use on specially designed and fully guarded machines and are subject to the following maximum thickness and hole size limitations.

Wheel diameter Max. thickness (inch)
6 inch and smaller 3⁄18
Larger than 6 inches to 12 inches ¼
Larger than 12 inches to 23 inches
Larger than 23 inches ½
Maximum hole size for cutting-off wheels should not be larger than ¼-wheel diameter.
Abrasive wheel means a cutting tool consisting of abrasive grains held together by organic or inorganic bonds. Diamond and reinforced wheels are included.
Organic wheels means wheels which are bonded by means of an organic material such as resin, rubber, shellac, or other similar bonding agent.
Inorganic wheels means wheels which are bonded by means of inorganic material such as clay, glass, porcelain, sodium silicate, magnesium oxychloride, or metal. Wheels bonded with clay, glass, porcelain or related ceramic materials are characterized as "vitrified bonded wheels."
As used in 1910.216, unless the context clearly requires otherwise, the following mills and calenders in the rubber and plastic industries terms shall have the meanings prescribed in this paragraph.
Bite means the nip point between any two inrunning rolls.
Calender means a machine equipped with two or more metal rolls revolving in opposite directions and used for continuously sheeting or plying up rubber and plastics compounds and for frictioning or coating materials with rubber and plastics compounds.
Mill means a machine consisting of two adjacent metal rolls, set horizontally, which revolve in opposite directions (i.e., toward each other as viewed from above) used for the mechanical working of rubber and plastics compounds.
As used in 1910.217, unless the context clearly requires otherwise, the following power press terms shall have the meaning prescribed in this paragraph.
Antirepeat means the part of the clutch/brake control system designed to limit the press to a single stroke if the tripping means is held operated. Antirepeat requires release of all tripping mechanisms before another stroke can be initiated. "Antirepeat" is also called single stroke reset or reset circuit.
Brake means the mechanism used on a mechanical power press to stop and/or hold the crankshaft, either directly or through a gear train, when the clutch is disengaged.
Bolster plate means the plate attached to the top of the bed of the press having drilled holes or T-slots for attaching the lower die or die shoe.
Clutch means the coupling mechanism used on a mechanical power press to couple the flywheel to the crankshaft, either directly or through a gear train.
Full revolution clutch means a type of clutch that, when tripped, cannot be disengaged until the crankshaft has completed a full revolution and the press slide a full stroke.
Part revolution clutch means a type of clutch that can be disengaged at any point before the crankshaft has completed a full revolution and the press slide a full stroke.
Direct drive means the type of driving arrangement wherein no clutch is used; coupling and decoupling of the driving torque is accomplished by energization and deenergization of a motor. Even though not employing a clutch, direct drives match the operational characteristics of "part revolution clutches" because the driving power may be disengaged during the stroke of the press.
Concurrent means acting in conjunction, and is used to describe a situation wherein two or more controls exist in an operated condition at the same time.
Continuous means uninterrupted multiple strokes of the slide without intervening stops (or other clutch control action) at the end of individual strokes.
Counterbalance means the mechanism that is used to balance or support the weight of the connecting rods, slide, and slide attachments.
Device means a press control or attachment that:
Restrains the operator from inadvertently reaching into the point of operation, or
Prevents normal press operation if the operator's hands are inadvertently within the point of operation, or
Automatically withdraws the operator's hands if the operator's hands are inadvertently within the point of operation as the dies close, or
Prevents the initiation of a stroke, or stops of stroke in progress, when there is an intrusion through the sensing field by any part of the operator's body or by any other object.
Presence sensing device means a device designed, constructed and arranged to create a sensing field or area that signals the clutch/brake control to deactivate the clutch and activate the brake of the press when any part of the operator's body or a hand tool is within such field or area.
Gate or movable barrier device means a movable barrier arranged to enclose the point of operation before the press stroke can be started.
Holdout or restraint device means a mechanism, including attachments for operator's hands, that when anchored and adjusted prevent the operator's hands from entering the point of operation.
Pull-out device means a mechanism attached to the operator's hands and connected to the upper die or slide of the press, that is designed, when properly adjusted, to withdraw the operator's hands as the dies close, if the operator's hands are inadvertently within the point of operation.
Sweep device means a single or double arm (rod) attached to the upper die or slide of the press and designed to move the operator's hands to a safe position as the dies close, if the operator's hands are inadvertently within the point of operation.
Two hand control device means a two hand trip that further requires concurrent pressure from both hands of the operator during a substantial part of the die-closing portion of the stroke of the press.
Die means the tooling used in a press for cutting or forming material. An upper and a lower die make a complete set.
Die builder means any person who builds dies for power presses.
Die set means a tool holder held in alignment by guide posts and bushings and consisting of a lower shoe, an upper shoe or punch holder, and guide posts and bushings.
Die setter means an individual who places or removes dies in or from mechanical power presses, and who, as a part of his duties, makes the necessary adjustments to cause the tooling to function properly and safely.
Die setting means the process of placing or removing dies in or from a mechanical power press, and the process of adjusting the dies, other tooling and safeguarding means to cause them to function properly and safely.
Die shoe means a plate or block upon which a die holder is mounted. A die shoe functions primarily as a base for the complete die assembly, and, when used, is bolted or clamped to the bolster plate or the face of slide.
Ejector means a mechanism for removing work or material from between the dies.
Face of slide means the bottom surface of the slide to which the punch or upper die is generally attached.
Feeding means the process of placing or removing material within or from the point of operation.
Automatic feeding means feeding wherein the material or part being processed is placed within or removed from the point of operation by a method or means not requiring action by an operator on each stroke of the press.
Semiautomatic feeding means feeding wherein the material or part being processed is placed within or removed from the point of operation by an auxiliary means controlled by operator on each stroke of the press.
Manual feeding means feeding wherein the material or part being processed is handled by the operator on each stroke of the press.
Foot control means the foot operated control mechanism designed to be used with a clutch or clutch/brake control system.
Foot pedal means the foot operated lever designed to operate the mechanical linkage that trips a full revolution clutch.
Guard means a barrier that prevents entry of the operator's hands or fingers into the point of operation.
Die enclosure guard means an enclosure attached to the die shoe or stripper, or both, in a fixed position.
Fixed barrier guard means a die space barrier attached to the press frame.
Interlocked press barrier guard means a barrier attached to the press frame and interlocked so that the press stroke cannot be started normally unless the guard itself, or its hinged or movable sections, enclose the point of operation.
Adjustable barrier guard means a barrier requiring adjustment for each job or die setup.
Guide post means the pin attached to the upper or lower die shoe operating within the bushing on the opposing die shoe, to maintain the alignment of the upper and lower dies.
Hand feeding tool means any hand held tool designed for placing or removing material or parts to be processed within or from the point of operation.
Inch means an intermittent motion imparted to the slide (on machines using part revolution clutches) by momentary operation of the "Inch" operating means. Operation of the "Inch" operating means engages the driving clutch so that a small portion of one stroke or indefinite stroking can occur, depending upon the length of time the "Inch" operating means is held operated. "Inch" is a function used by the die setter for setup of dies and tooling, but is not intended for use during production operations by the operator.
Jog means an intermittent motion imparted to the slide by momentary operation of the drive motor, after the clutch is engaged with the flywheel at rest.
Knockout means a mechanism for releasing material from either die.
Liftout means the mechanism also known as knockout.
Operator's station means the complete complement of controls used by or available to an operator on a given operation for stroking the press.
Pinch point means any point other than the point of operation at which it is possible for a part of the body to be caught between the moving parts of a press or auxiliary equipment, or between moving and stationary parts of a press or auxiliary equipment or between the material and moving part or parts of the press or auxiliary equipment.
Point of operation means the area of the press where material is actually positioned and work is being performed during any process such as shearing, punching, forming, or assembling.
Press means a mechanically powered machine that shears, punches, forms or assembles metal or other material by means of cutting, shaping, or combination dies attached to slides. A press consists of a stationary bed or anvil, and a slide (or slides) having a controlled reciprocating motion toward and away from the bed surface, the slide being guided in a definite path by the frame of the press.
Repeat means an unintended or unexpected successive stroke of the press resulting from a malfunction.
Safety block means a prop that, when inserted between the upper and lower dies or between the bolster plate and the face of the slide, prevents the slide from falling of its own deadweight.
Single stroke means one complete stroke of the slide, usually initiated from a full open (or up) position, followed by closing (or down), and then a return to the full open position.
Single stroke mechanism means an arrangement used on a full revolution clutch to limit the travel of the slide to one complete stroke at each engagement of the clutch.
Slide means the main reciprocating press member. A slide is also called a ram, plunger, or platen.
Stop control means an operator control designed to immediately deactivate the clutch control and activate the brake to stop slide motion.
Stripper means a mechanism or die part for removing the parts or material from the punch.
Stroking selector means the part of the clutch/brake control that determines the type of stroking when the operating means is actuated. The stroking selector generally includes positions for "Off" (Clutch Control), "Inch," "Single Stroke," and "Continuous" (when Continuous is furnished).
Trip or (tripping) means activation of the clutch to "run" the press.
Turnover bar means a bar used in die setting to manually turn the crankshaft of the press.
Two-hand trip means a clutch actuating means requiring the concurrent use of both hands of the operator to trip the press.
Unitized tooling means a type of die in which the upper and lower members are incorporated into a self-contained unit so arranged as to hold the die members in alignment.
Control system means sensors, manual input and mode selection elements, interlocking and decision-making circuitry, and output elements to the press operating mechanism.
Brake monitor means a sensor designed, constructed, and arranged to monitor the effectiveness of the press braking system.
Presence sensing device initiation means an operating mode of indirect manual initiation of a single stroke by a presence sensing device when it senses that work motions of the operator, related to feeding and/or removing parts, are completed and all parts of the operator's body or hand tools are safely clear of the point of operation.
Safety system means the integrated total system, including the pertinent elements of the press, the controls, the safeguarding and any required supplemental safeguarding, and their interfaces with the operator, and the environment, designed, constructed and arranged to operate together as a unit, such that a single failure or single operating error will not cause injury to personnel due to point of operation hazards.
Authorized person means one to whom the authority and responsibility to perform a specific assignment has been given by the employer.
Certification or certify means, in the case of design certification/validation, that the manufacturer has reviewed and tested the design and manufacture, and in the case of installation certification/validation and annual recertification/revalidation, that the employer has reviewed and tested the installation, and concludes in both cases that the requirements of 1910.217 (a) through (h) and Appendix A have been met. The certifications are made to the validation organization.
Validation or validate means for PSDI safety systems that an OSHA recognized third-party validation organization:
For design certification/validation has reviewed the manufacturer's certification that the PSDI safety system meets the requirements of 1910.217 (a) through (h) and Appendix A and the underlying tests and analyses performed by the manufacturer, has performed additional tests and analyses which may be required by 1910.217 (a) through (h) and Appendix A, and concludes that the requirements of 1910.217 (a) through (h) and Appendix A have been met; and
For installation certification/validation and annual recertification/revalidation has reviewed the employer's certification that the PSDI safety system meets the requirements of 1910.217 (a) through (h) and Appendix A and the underlying tests performed by the employer, has performed additional tests and analyses which may be required by 1910.217 (a) through (h) and Appendix A, and concludes that the requirements of 1910.217 (a) through (h) and Appendix A have been met.
Certification/validation and certify/validate means the combined process of certification and validation.
As used in 1910.218, unless the context clearly requires otherwise, the following forging and hot metal terms shall have the meaning prescribed in this paragraph.
Forging means the product of work on metal formed to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. Forging hammers, counterblow equipment and high-energy-rate forging machines impart impact to the workpiece, while most other types of forging equipment impart squeeze pressure in shaping the stock. Some metals can be forged at room temperature, but the majority of metals are made more plastic for forging by heating.
Open framehammers (or blacksmith hammers) mean hammers used primarily for the shaping of forgings by means of impact with flat dies. Open frame hammers generally are so constructed that the anvil assembly is separate from the operating mechanism and machine supports; it rests on its own independent foundation. Certain exceptions are forging hammers made with frame mounted on the anvil; e.g., the smaller, single-frame hammers are usually made with the anvil and frame in one piece.
Steam hammers mean a type of drop hammer where the ram is raised for each stroke by a double-action steam cylinder and the energy delivered to the workpiece is supplied by the velocity and weight of the ram and attached upper die driven downward by steam pressure. Energy delivered during each stroke may be varied.
Gravity hammers mean a class of forging hammer wherein energy for forging is obtained by the mass and velocity of a freely falling ram and the attached upper die. Examples: board hammers and air-lift hammers.
Forging presses mean a class of forging equipment wherein the shaping of metal between dies is performed by mechanical or hydraulic pressure, and usually is accomplished with a single workstroke of the press for each die station.
Trimming presses mean a class of auxiliary forging equipment which removes flash or excess metal from a forging. This trimming operation can also be done cold, as can coining, a product sizing operation.
High-energy-rate forging machines mean a class of forging equipment wherein high ram velocities resulting from the sudden release of a compressed gas against a free piston impart impact to the workpiece.
Forging rolls mean a class of auxiliary forging equipment wherein stock is shaped between power driven rolls bearing contoured dies. Usually used for preforming, roll forging is often employed to reduce thickness and increase length of stock.
Ring rolls mean a class for forging equipment used for shaping weldless rings from pierced discs or thick-walled, ring-shaped blanks between rolls which control wall thickness, ring diameter, height and contour.
Bolt-headers mean the same as an upsetter or forging machine except that the diameter of stock fed into the machine is much smaller, i.e., commonly three-fourths inch or less.
Rivet making machines mean the same as upsetters and boltheaders when producing rivets with stock diameter of 1-inch or more. Rivet making with less than 1-inch diameter is usually a cold forging operation, and therefore not included in this subpart.
Upsetters (or forging machines, or headers) type of forging equipment, related to the mechanical press, in which the main forming energy is applied horizontally to the workpiece which is gripped and held by prior action of the dies.
As used in 1910.219, unless the context clearly requires otherwise, the following mechanical power-transmission guarding terms shall have the meaning prescribed in this paragraph.
Belts include all power transmission belts, such as flat belts, round belts, V-belts, etc., unless otherwise specified.
Belt shifter means a device for mechanically shifting belts from tight to loose pulleys or vice versa, or for shifting belts on cones of speed pulleys.
Belt pole (sometimes called a "belt shipper" or "shipper pole,") means a device used in shifting belts on and off fixed pulleys on line or countershaft where there are no loose pulleys.
Exposed to contact means that the location of an object is such that a person is likely to come into contact with it and be injured.
Flywheels include flywheels, balance wheels, and flywheel pulleys mounted and revolving on crankshaft of engine or other shafting.
Maintenance runway means any permanent runway or platform used for oiling, maintenance, running adjustment, or repair work, but not for passageway.
Nip-point belt and pulley guard means a device which encloses the pulley and is provided with rounded or rolled edge slots through which the belt passes.
Point of operation means that point at which cutting, shaping, or forming is accomplished upon the stock and shall include such other points as may offer a hazard to the operator in inserting or manipulating the stock in the operation of the machine.
Prime movers include steam, gas, oil, and air engines, motors, steam and hydraulic turbines, and other equipment used as a source of power.
Sheaves mean grooved pulleys, and shall be so classified unless used as flywheels.

[39 FR 23502, June 27, 1974, as amended at 39 FR 41846, Dec. 3, 1974; 53 FR 8353, Mar. 14, 1988]
One or more methods of machine guarding shall be provided to protect the operator and other employees in the machine area from hazards such as those created by point of operation, ingoing nip points, rotating parts, flying chips and sparks. Examples of guarding methods are-barrier guards, two-hand tripping devices,electronic safety devices, etc.
Guards shall be affixed to the machine where possible and secured elsewhere if for any reason attachment to the machine is not possible. The guard shall be such that it does not offer an accident hazard in itself.
Point of operation guarding.
Point of operation is the area on a machine where work is actually performed upon the material being processed.
The point of operation of machines whose operation exposes an employee to injury, shall be guarded. The guarding device shall be in conformity with any appropriate standards therefor, or, in the absence of applicable specific standards, shall be so designed and constructed as to prevent the operator from having any part of his body in the danger zone during the operating cycle.
Special handtools for placing and removing material shall be such as to permit easy handling of material without the operator placing a hand in the danger zone. Such tools shall not be in lieu of other guarding required by this section, but can only be used to supplement protection provided.
The following are some of the machines which usually require point of operation guarding:
Barrels, containers, and drums. Revolving drums, barrels, and containers shall be guarded by an enclosure which is interlocked with the drive mechanism, so that the barrel, drum, or container cannot revolve unless the guard enclosure is in place.
When the periphery of the blades of a fan is less than seven (7) feet above the floor or working level, the blades shall be guarded. The guard shall have openings no larger than one-half (½) inch.
Anchoring fixed machinery. Machines designed for a fixed location shall be securely anchored to prevent walking or moving.
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.
Arbors and mandrels shall be constructed so as to have firm and secure bearing and be free from play.
Any automatic cutoff saw that strokes continuously without the operator being able to control each stroke shall not be used.
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.
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.
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.
Hinged saw tables shall be so constructed that the table can be firmly secured in any position and in true alignment with the saw.
All belts, pulleys, gears, shafts, and moving parts shall be guarded in accordance with the specific requirements of 1910.219.
It is recommended that each power-driven woodworking machine be provided with a disconnect switch that can be locked in the off position.
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.
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.
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.
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.
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.
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.
On machines driven by belts and shafting, a locking-type belt shifter or an equivalent positive device shall be used.
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.
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.
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.
Each operating treadle shall be protected against unexpected or accidental tripping.
Feeder attachments shall have the feed rolls or other moving parts so covered or guarded as to protect the operator from hazardous points.
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.
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.
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.
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.
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.
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.
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 ½ inches in front of the nip point between the front roll and the work.
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.
The requirements of this paragraph are also applicable to sliding cutoff saws mounted above the table.
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.
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.
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.
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.
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
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.
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.
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.
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 ½ inches by ¾ 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".
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.
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.
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.
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.
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 ½ inches when tables are set or aligned with each other for zero cut.
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.
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.
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.
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.
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.
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.
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.
Safety-bit chucks with no projecting set screws shall be used.
Boring bits should be provided with a guard that will enclose all portions of the bit and chuck above the material being worked.
The top of the cutting chain and driving mechanism shall be enclosed.
If there is a counterweight, one of the following or equivalent means shall be used to prevent its dropping:
It shall be bolted to the bar by means of a bolt passing through both bar and counterweight;
A bolt shall be put through the extreme end of the bar;
Where the counterweight does not encircle the bar, a safety chain shall be attached to it;
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.
Universal joints on spindles of boring machines shall be completely enclosed in such a way as to prevent accidental contact by the operator.
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.
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.
All double-spindle shapers shall be provided with a spindle starting and stopping device for each spindle.
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 116 inch in thickness, and if cast iron is used, it shall be not less than three-sixteenths inch in thickness.
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.
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.
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.
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.
Cutting heads on wood-turning lathes, whether rotating or not, shall be covered as completely as possible by hoods or shields.
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.
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.
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.
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.
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.
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.
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.
Veneer slicer knives shall be guarded to prevent accidental contact with knife edge, at both front and rear.
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.
Sprockets on chain or slat-belt conveyors shall be enclosed.
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.
Power-driven guillotine veneer cutters, except continuous feed trimmers, shall be equipped with:
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
Bearings shall be kept free from lost motion and shall be well lubricated.
Arbors of all circular saws shall be free from play.
Sharpening or tensioning of saw blades or cutters shall be done only by persons of demonstrated skill in this kind of work.
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.
All cracked saws shall be removed from service.
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.
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.
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.
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.
Operators shall not ride the carriage of a veneer slicer.

[39 FR 23502, June 27, 1974, as amended at 43 FR 49750, Oct. 24, 1978; 49 FR 5323, Feb. 10, 1984]
Abrasive wheels shall be used only on machines provided with safety guards as defined in the following paragraphs of this section, except:
Wheels used for internal work while within the work being ground;
Mounted wheels, used in portable operations, 2 inches and smaller in diameter; and
Types 16, 17, 18, 18R, and 19 cones, plugs, and threaded hole pot balls where the work offers protection.
The safety guard shall cover the spindle end, nut, and flange projections. The safety guard shall be mounted so as to maintain proper alignment with the wheel, and the strength of the fastenings shall exceed the strength of the guard, except:
Safety guards on all operations where the work provides a suitable measure of protection to the operator, may be so constructed that the spindle end, nut, and outer flange are exposed; and where the nature of the work is such as to entirely cover the side of the wheel, the side covers of the guard may be omitted; and
The spindle end, nut, and outer flange may be exposed on machines designed as portable saws.
Grinding machines shall be equipped with flanges in accordance with paragraph (c) of this section.
On offhand grinding machines, work rests shall be used to support the work. They shall be of rigid construction and designed to be adjustable to compensate for wheel wear. Work rests shall be kept adjusted closely to the wheel with a maximum opening of one-eighth inch to prevent the work from being jammed between the wheel and the rest, which may cause wheel breakage. The work rest shall be securely clamped after each adjustment. The adjustment shall not be made with the wheel in motion.
Natural sandstone wheels and metal, wooden, cloth, or paper discs, having a layer of abrasive on the surface are not covered by this section.
Cup wheels (Types 6 and 11) shall be protected by:
Safety guards as specified in paragraphs (b) (1) through (10) of this section;
Band type guards as specified in paragraph (b) (11) of this section; and
Special "Revolving Cup Guards" which mount behind the wheel and turn with it. They shall be made of steel or other material with adequate strength and shall enclose the wheel sides upward from the back for one-third of the wheel thickness. The mounting features shall conform with all requirements of this section. It is necessary to maintain clearance between the wheel side and the guard. This clearance shall not exceed one-sixteenth inch.
The maximum exposure angles specified in paragraphs (b) (3) through (8) of this section shall not be exceeded. Visors or other accessory equipment shall not be included as a part of the guard when measuring the guard opening, unless such equipment has strength equal to that of the guard.
The angular exposure of the grinding wheel periphery and sides for safety guards used on machines known as bench and floor stands should not exceed 90 deg. or one-fourth of the periphery. This exposure shall begin at a point not more than 65 deg. above the horizontal plane of the wheel spindle. (See Figures O-6 and O-7 and paragraph (b)(9) of this section.)

Figure No. O-6                                             Figure No. O-7

Wherever the nature of the work requires contact with the wheel below the horizontal plane of the spindle, the exposure shall not exceed 125 deg. (See Figures O-8 and O-9.)

Figure No. O-8                                    Figure No. O-9
The maximum angular exposure of the grinding wheel periphery and sides for safety guards used on cylindrical grinding machines shall not exceed 180 deg. This exposure shall begin at a point not more than 65 deg. above the horizontal plane of the wheel spindle. (See Figures O-10 and O-11 and subparagraph (9) of this paragraph.)

Figure No. O-10                                                Figure No. O-11
The maximum angular exposure of the grinding wheel periphery and sides for safety guards used on cutting-off machines and on surface grinding machines which employ the wheel periphery shall not exceed 150 deg. This exposure shall begin at a point not less than 15 deg. below the horizontal plane of the wheel spindle. (See Figures O-12 and O-13)

Figure No. O-12                                          Figure No. O-13
The maximum angular exposure of the grinding wheel periphery and sides for safety guards used on machines known as swing frame grinding machines shall not exceed 180 deg., and the top half of the wheel shall be enclosed at all times. (See Figures O-14 and O-15.)

Figure No. O-14                                              Figure No. O-15
The maximum angular exposure of the grinding wheel periphery and sides for safety guards used on grinders known as automatic snagging machines shall not exceed 180 deg. and the top half of the wheel shall be enclosed at all times. (See Figures O-14 and O-15.)
Where the work is applied to the wheel above the horizontal centerline, the exposure of the grinding wheel periphery shall be as small as possible and shall not exceed 60 deg. (See Figures O-16 and O-17.)

Figure No. O-16                                              Figure No. O-17
Safety guards of the types described in Subparagraphs (3) and (4) of this paragraph, where the operator stands in front of the opening, shall be constructed so that the peripheral protecting member can be adjusted to the constantly decreasing diameter of the wheel. The maximum angular exposure above the horizontal plane of the wheel spindle as specified in paragraphs (b)(3) and (4) of this section shall never be exceeded, and the distance between the wheel periphery and the adjustable tongue or the end of the peripheral member at the top shall never exceed one-fourth inch. (See Figures O-18, O-19, O-20, O-21, O-22, and O-23.)

Figure No. O-18                                        Figure No. O-19

CORRECT
Showing adjustable tongue giving required angular protection for all sizes of wheel used.

Figure No. O-20                                            Figure No. O-21

CORRECT
Showing movable guard with opening small enough to give required protection for smallest size wheel used.

Figure No. O-22                                         Figure No. O-23

INCORRECT
Showing movable guard with size of opening correct for full size wheel but too large for smaller wheels.
See Figures O-36 and O-37 and Table O-9 for minimum basic thickness of peripheral and side members for various types of safety guards and classes of service.

Figure No. O-36                                                                                          Figure No. O-37


TABLE O-9 - MINIMUM BASIC THICKNESS OF PERIPHERAL AND
SIDE MEMBERS FOR SAFETY GUARDS

(In inches)
Material used in construction of guard Maximum thickness of grinding wheel Grinding wheel diameters
3 to 6 inches Over 6 to 12 inches Over 12 to 16 inches
A B A B A B
Material satisfactory(1) for speeds up to 8,000 SFPM. 2 ¼ ¼ 516 ½
4 516 516 516 ½
6 516 ½ 716 ½
8 916 ¾
10 ¾ 1116 ¾
16 1 ⅛ 1
20
Cast iron (min. tensile strength 20,000 p.s.i.) Class 20.
Material satisfactory(1) for speeds up to 9,000 SFPM. 2 ¼ ¼ 516 ½
4 516 516 516 ½
6 516 ½ 716 ½
8 ½ 716 ½
10 ½ 716 ½
16 1316 1116
20
Malleable iron (min. tensile strength 50,000 p.s.i.) Grade 32510.
Material satisfactory(1) for speeds up to 16,000 SFPM. 2 ¼ ¼ 516 516
4 ¼ ¼ ½ ½ ½ ½
6 ¼ ¾ ¾
8 ¾ ¾
10 1 1
16 1 ¼ 1 ⅛
20
Steel castings (min. tensile strength 60,000 p.s.i.) Grade V60-30.
Structural steel(min. tensile strength 60,000 p.s.i.) 2 116 516 ¼ 516 ¼
4 116 516 516
6 316 116 ½ 716
8 ½ 916 716
10 916 716 ½ ½
16 916
20
Material used in construction of guard Maximum thickness of grinding wheel Grinding wheel diameters
Over 16 to 20 inches Over 20 to 24 inches
A B A B
Material satisfactory(1) for speeds up to 8,000 SFPM. 2 ½
4 ¾ 1
6 1 1 ⅛ ¾
8 1 ¾ 1 ⅛ ¾
10 1 ¾ 1 ⅛ ¾
16 1 ¼ 1 1 516 1
20 1 ⅜ 1 ⅛ 1 ⅜ 1 ⅛
Cast iron (min. tensile strength 20,000 p.s.i.) Class 20.
Material satisfactory(1) for speeds up to 9,000 SFPM. 2 ½ ¾
4 ½ ¾
6 ¾
8 ¾
10 ¾
16 1316 1116 1 ¾
20 ¾ 1 ¾
Malleable iron (min. tensile strength 50,000 p.s.i.) Grade 32510.
Material satisfactory(1) for speeds up to 16,000 SFPM. 2 ½ 716 ½
4 916 ½ ½
6 ¾ 1316 1116
8 ¾ ¾
10 1 1 ⅛ 1516
16 1 ¼ 1 ⅛ 1 ¼ 1 ⅛
20 1 ⅜ 1 ¼ 1 ⅜ 1 ¼
Steel castings (min. tensile strength 60,000 p.s.i.) Grade V60-30
Structural steel (min. tensile strength 60,000 p.s.i.) 2 516 ¼ 416 ¼
4 516 516
6 716 716
8 916 716 9
10 ½ ½
16 ¾ ¾
20 1316 1116 1316 1116
Material used in construction of guard Maximum thickness of grinding wheel Grinding wheel diameters
Over 24 to 30 inches Over 30 to 48 inches
A B A B
Material satisfactory(1) for speeds up to 8,000 SFPM. 2 1 ¾ 1 ¼ 1
4 1 ⅛ ¾ 1 ⅜ 1
6 1 ¼ 1 ½ 1 ⅛
8 1 ¼ 1 ½ 1 ⅛
10 1 ¼ 1 ½ 1 ⅛
16 1 716 1 116 1 ¾ 1 ⅜
20 1 ½ 1 ⅜ 2 1 ⅝
Cast iron (min. tensile strength 20,000 p.s.i.) Class 20.
Material satisfactory(1) for speeds up to 9,000 SFPM. 2 ¾ 1
4 ¾ 1 ⅛
6 1 ¾ 1 ¼
8 1 ¾ 1 ¼
10 1 ¾ 1 ¼
16 1 ⅛ 1 ⅜ 1
20 1 ⅛ 1 ½ 1 ⅛
Malleable iron (min. tensile strength 50,000 p.s.i.) Grade 32510.
Material satisfactory(1) for speeds up to 16,000 SFPM. 2 ¾ ¾
4 ¾ 1 ¾
6 1316 1116 1 ⅛ ¾
8 1516 1316 1 ⅜ 1
10 1 ⅛ 1 1 716 1 116
16 1 ¼ 1 ⅛ 1 1316 1 716
20 1 716 1 516 2 116 1 1116
Steel castings (min. tensile strength 60,000 p.s.i.) Grade V60-30
Structural steel (min. tensile strength 60,000 p.s.i.) 2 516 ½
4 516 ½
6 716 ¾ ½
8
10
16 1316 1116 1 116 1316
20 ¾ 1 316 1516
     Footnote(1) The recommendations listed in the above table are guides for the conditions stated. Other material, designs or dimensions affording equal or superior protection are also acceptable.
If operating speed does not exceed 8,000 surface feet per minute cast iron safety guards, malleable iron guards or other guards as described in paragraph (b)(10)(iii) of this section shall be used.
Cast steel, or structural steel, safety guards as specified in Figures O-36 and O-37 and Table O-9 shall be used where operating speeds of wheels are faster than 8,000 surface feet per minute up to a maximum of 16,000 surface feet per minute.
For cutting-off wheels 16 inches diameter and smaller and where speed does not exceed 16,000 surface feet per minute, cast iron or malleable iron safety guards as specified in Figures O-36 and O-37, and in Table O-9 shall be used.
For cutting-off wheels larger than 16 inches diameter and where speed does not exceed 14,200 surface feet per minute, safety guards as specified in Figures O-27 and O-28, and in Table O-1 shall be used.

                                                                                  
Figure No. O-27                                                                            Figure No. O-28


TABLE O-1 - MINIMUM BASIC THICKNESS FOR PERIPHERAL AND SIDE
         MEMBERS FOR SAFETY GUARDS USED WITH CUTTING-OFF
WHEELS
Material
used
in
construction
of
guard
Maximum
thickness
of
cutting
off
wheel
Speed
not
to
exceed
Cutting off wheel diameters
6 to 11
inches
Over 11 to
20 inches
Over 20 to
30 inches
A B A B A B
Structural
steel (min.
tensile
60,000
p.s.i.).
½ inch
or less...
14,200
SEPM...
116 116 332 332
½ inch
or less...
16,000
SEPM...
332 316
Material
used
in
construction
of
guard
Maximum
thickness
of
cutting
off
wheel
Speed
not
to
exceed
Cutting off wheel diameters
Over 30 to
48 inches
Over 48 to
72 inches
A B A B
Structural
steel (min.
tensile
60,000
p.s.i.).
½ inch
or less...
14,200
SEPM...
316 316 ¼ ¼
½ inch
or less...
16,000
SEPM...
¼ 316 516 ¼
For thread grinding wheels not exceeding 1 inch in thickness cast iron or malleable iron safety guards as specified in Figures O-36 and O-37, and in Table O-9 shall be used.
Band type guards-general specifications. Band type guards shall conform to the following general specifications:
The bands shall be of steel plate or other material of equal or greater strength. They shall be continuous, the ends being either riveted, bolted, or welded together in such a manner as to leave the inside free from projections.
The inside diameter of the band shall not be more than 1 inch larger than the outside diameter of the wheel, and shall be mounted as nearly concentric with the wheel as practicable.
The band shall be of sufficient width and its position kept so adjusted that at no time will the wheel protrude beyond the edge of the band a distance greater than that indicated in Figure O-29 and in Table O-2 or the wall thickness (W), whichever is smaller.

Figure No. O-29


TABLE O-2 - EXPOSURE VERSUS WHEEL THICKNESS
[in inches]
Overall thickness of
wheel (T)
Maximum exposure of
wheel (C)
½ ¼
1 ½
2 ¾
3 1
4 1 ½
5 and over 2
Abrasive wheel machinery guards shall meet the design specifications of the American National Standard Safety Code for the Use, Care, and Protection of Abrasive Wheels, ANSI B7.1-1970, which is incorporated by reference as specified in Sec. 1910.6. This requirement shall not apply to natural sandstone wheels or metal, wooden, cloth, or paper discs, having a layer of abrasive on the surface.
All abrasive wheels shall be mounted between flanges which shall not be less than one-third the diameter of the wheel.
Portable wheels with threaded inserts or projecting studs.
Abrasive discs (inserted nut, inserted washer and projecting stud type).
Cylinders, cup, or segmental wheels that are mounted in chucks.
Cutting-off wheels, Types 1 and 27A (see paragraphs (c)(1) (ii) and (iii) of this section).
Type 1 cutting-off wheels are to be mounted between properly relieved flanges which have matching bearing surfaces. Such flanges shall be at least one-fourth the wheel diameter.
Type 27A cutting-off wheels are designed to be mounted by means of flat, not relieved, flanges having matching bearing surfaces and which may be less than one-third but shall not be less than one-fourth the wheel diameter. (See Figure O-24 for one such type of mounting.)

Figure No. O-24
There are three general types of flanges:
Straight relieved flanges (see Figure O-32);

Figure No. O-32
Driving flange secured to spindle.
Straight unrelieved flanges (see Figure O-30);

Figure No. O-30
Adaptor flanges (see Figures O-33 and O-34);
FIGURE NO. O-33
Central Nut Mounting
Driving flange secured to spindle.


FIGURE NO. O-34
Multiple Screw Mounting
Driving flange secured to spindle.