Guarding of Metal-Turning Machinery and Machines

Among the more severe injuries that can occur in the workplace are associated with worker contact with moving metal machine parts. The list of injuries caused by worker contact with moving metal machine parts is numerous and can include amputations of limbs and fingers, crushed fingers and/or hands, lacerations, and abrasions. Also, contact with moving metal machine parts can set off chain reactions that can even prove fatal for workers. Amputations occur to fingers, hands, feet, and other body parts, mostly through compression, crushing, or by getting caught between or struck by objects. Most amputations involve fingertips. Amputation is one of the most severe and crippling types of injuries in the occupational workplace, and often results in permanent disability.

Employee exposure to unguarded or inadequately guarded machines is prevalent in many workplaces. As a result, as reported by the Occupational Health and Safety Administration (OSHA), “…workers who operate and maintain machinery suffer approximately 18,000 amputations, lacerations, crushing injuries, abrasions, and over 800 deaths per year” . In fiscal year 2020, of the top ten most frequently cited standards following inspections of work sites by OSHA, the tenth-ranked most cited violation by OSHA was associated with machinery and machine guarding . Whenever operation of a machine or any activity in its vicinity poses the risk of injury to workers, safety mechanisms must be put in place. Safeguards are vital for ensuring maximum protection for workers in an industrial environment.

To protect workers from these preventable injuries, it is essential that employers institute safeguards to any machine part, function, or process that may cause injury. The hazards associated with the operation of a machine that may cause accidental contact and injury to an employee or others in the vicinity must be eliminated or controlled through adequate guarding and employee training.

All machines consist of the following three fundamental areas:

  1. Point of Operation , which is where work is conducted on the material, such as cutting, shaping, boring, or forming of stock.
  2. Power Transmission Device , which is all components of the mechanical system which transmit energy to the part of the machine conducting the work. These components include flywheels, pulleys, belts, connecting rods, couplings, cams, spindles, chains, cranks, and gears.
  3. Operating Controls , which are mechanical or electrical power controls that shall be provided on each machine to make it possible for the operator to cut off the power from each machine without leaving his/her position at the point of operation.

Despite all machines having the same basic components, their safeguarding needs widely differ due to varying physical characteristics and operator involvement.

As indicated by OSHA, a wide variety of mechanical motions and actions may present hazards to the worker. These can include the movement of rotating members, reciprocating arms, moving belts, meshing gears, cutting teeth, and any parts that impact or shear. These different types of hazardous mechanical motions and actions are standard in varying combinations to nearly all machines, and recognizing them is the first step toward protecting workers from the danger they present. The basic types of hazardous mechanical motions and actions are:


  • Rotating : Collars, couplings, cams, clutches, flywheels, shaft ends, spindles, meshing gears, and horizontal or vertical shafting are some examples of common rotating mechanisms which may be hazardous. The danger increases when projections such as bolts, nicks, abrasions, and projecting keys or set screws are exposed on rotating parts.
  • In-Running Nip Points : There are three main types of in-running nip points.
    • On rotating parts: Parts can rotate in opposite directions while their axes are parallel to each other. These parts may be in contact (producing a nip point) or in proximity. This danger is common on machines with intermeshing gears, rolling mills, and calenders.
    • Between rotating and tangentially moving parts: Some examples would be the point of contact between a power transmission belt and its pulley, a chain and a sprocket, and a rack and pinion.
    • Between rotating machine components: Between rotating and fixed parts which create a shearing, crushing, or abrading action. Examples are spoked handwheels or flywheels, screw conveyors, or the periphery of an abrasive wheel and an incorrectly adjusted work rest and tongue.
  • Reciprocating: Back-and-forth or up-and-down motions during which a worker may be struck by or caught between a moving and a stationary part.
  • Transversing: Movement in a straight, continuous line during which a worker may be struck or caught in a pinch or shear point by the moving part.


  • Cutting : Cutting action may involve rotating, reciprocating, or transverse motion. The danger of cutting action exists at the point of operation where finger, arm, and body injuries can occur and where flying chips or scrap material can strike the head, particularly around the eyes or face. Such hazards are present at the point of operation in cutting wood, metal, and other materials. Examples of mechanisms involving cutting hazards include bandsaws, circular saws, boring and drilling machines, turning machines (lathes), or milling machines.
  • Punching : Punching action results when power is applied to a slide (ram) for the purpose of blanking, drawing, or stamping metal or other materials. The danger of this type of action occurs at the point of operation where stock is inserted, held, and withdrawn by hand. Typical machines used for punching operations are power presses and iron workers.
  • Shearing: Shearing action involves applying power to a slide or knife to trim or shear metal or other materials. A hazard occurs at the point of operation where stock is inserted, held, and withdrawn. Examples of machines used for shearing operations are mechanically, hydraulically, or pneumatically powered shears.
  • Bending: Bending action results when power is applied to a slide to draw or stamp metal or other materials. A hazard occurs at the point of operation where stock is inserted, held, and withdrawn. Equipment that uses bending action includes power presses, press brakes, and tubing benders.

As indicated by OSHA, “Any machine part, function, or process which may cause injury must be safeguarded.” Guarding of machinery is the best way to prevent amputations and other injuries. Guards provide physical barriers to hazardous areas. They should be secure and strong, and workers should not be able to by-pass, remove, or tamper with them. Guards should not obstruct the operator’s view or prevent others from working.

OSHA requires employers to ensure the safety of all employees in the work environment, including by providing safeguards to moving parts of machinery to protect against injuries, amputations, and even death. Measures to provide protection to workers on the job site from moving parts of machinery and machines should be included in the preparation of a Health and Safety Plan (HASP), a Job Hazard Analysis (JHA), an Activity Hazard Analysis (AHA), or a Job Safety Analysis (JSA).

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OSHA Standards

OSHA standards with which an employer must comply are addressed under the “General Industry” scenario by 29 Code of Federal Regulations (CFR) 1910 Subpart O “Machinery and Machine Guarding” . Other scenarios under which an employer must comply with applicable OSHA standards and regulations or specific portions thereof on guarding include:

  • Construction Industry : 29 CFR 1926 Subpart I “Tools – Hand and Power”, more specifically 29 CFR 1926.300 through 307
  • Special Industries : 29 CFR 1910 Subpart R, which includes specific requirements for the textile industry, bakery equipment, and telecommunications.
  • Agriculture Industry : 29 CFR 1928.57, which summarizes guarding of farm field equipment, farmstead equipment, and cotton gins.
  • Maritime Industry : 29 CFR 1915, 1917, and 1918.

As the focus of this article is on the general requirements for all machinery under the General Industry scenario, the reader is referred to the citations previously listed for the other scenarios.

There are 28 OSHA-approved State Plans, operating state-wide occupational safety and health programs. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA's and may have different or more stringent requirements. Information on which states have OSHA-approved plans are at this link , and should be reviewed for the applicable State that one may be working in.

The OSHA general requirements under 29 Code of Federal Regulations (CFR) 1910 Subpart O that apply to the safeguarding of metal-turning equipment that an employer must comply with include:

Overall, the primary requirements for all machines under 29 CFR 1910.212 for the “General Industry” scenario are brief and are as follows.

  • 29 CFR 1910.212(a)(1): Types of guarding. 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.

With this regulation, OSHA requires that machine guarding be provided to protect the operators (and other employees) from all hazards. OSHA does not specify which types of safeguards should be used, but includes several examples such as fixed guards, interlocked guards, light curtains, and other similar devices.

  • 29 CFR 1910.212(a)(2): General requirements for machine guards. 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.

Under this regulation, machine guards are required by OSHA to be provided on all machines, and attached to the machine.

  • 29 CFR 1910.212(a)(3)(ii): 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.

Under this regulation, OSHA requires that the guards be designed such that it is not possible to reach the hazard by reaching over, around, under, or through the guard. Furthermore, under 29 CFR 1910.212(a)(3)(iv), OSHA lists some of the machinery that usually requires point of operation guarding: guillotine cutters, shears, alligator shears, power presses, milling machines, power saws, jointers, portable power tools, and forming rolls and calendars.

  • 29 CFR 1910.212(a)(4): 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.

Under this regulation, OSHA requires that guard enclosures are in place such that revolving drums, barrels, and containers cannot operate if the guard enclosure is not in place.

  • 29 CFR 1910.212(a)(5): Exposure of blades. 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 ( 1 2 ) inch.
  • 29 CFR 1910.212(b): Anchoring fixed machinery. Machines designed for a fixed location shall be securely anchored to prevent walking or moving.

Requirements for Safeguards

Although OSHA does not indicate the specific machine guards that should be used, OSHA has set out a few general requirements that a safeguard must meet to ensure maximum protection. The safeguarding system must have the following features:

  • Prevent contact with the moving part(s), keeping the workers’ hands, arms, or any other part safe. A well-designed safeguarding system is one that ensures that the operator cannot reach the moving part(s).
  • Secure, so that workers cannot take off or tamper with the safeguarding mechanism. Guards and safety devices must be durable to withstand the harsh industrial environment.
  • Protect the moving parts of the machinery from falling objects, making sure that no object falls into the moving part, effectively becoming a projectile and potentially injuring the worker(s).
  • Create no new hazards to the worker(s).
  • Allow safe lubrication, so that the machines remain in top condition and the downtime encountered by the employer is minimized.

An effective guarding system is one that is reliable, durable, and covers all the vulnerable spots during the operation of machinery.

During preparation of a Health and Safety Plan (HASP), a Job Hazard Analysis (JHA), an Activity Hazard Analysis (AHA), or a Job Safety Analysis (JSA), OSHA has a web-based tool that can be used to assist in the selection of the appropriate guarding for machinery and machines, and helping one to comply with the OSHA machine guarding standard. This tool is called the “Machine Guarding eTool” . On this web page, OSHA provides information to assist an employer to focus on recognizing and controlling common amputation hazards associated with the operation and use of certain types of machines. Another very useful source of information for employers and workers is the OSHA publication “Safeguarding Equipment and Protecting Employees from Amputations”  published in 2007.

JSAs are a useful tool that can aid the identification of changed conditions, which can help a work team to develop and agree on revised mitigations at their worksite. Those mitigation revisions can then be immediately documented with a management of change (MOC) annotation right on the JSA. That facilitates helping everybody to complete their tasks safely, in an efficient manner. Performing these MOC steps during reviews help to keep all team members engaged in thinking about their current work tasks and help eliminate potential hazards. A JSA worksheet provides employers so much value so inexpensively, it’s difficult to understand why anyone would not use a Job Safety Analysis for every project task.

Go to and test the referenced JSA software for free , and help your team work safely and go home at the end of each work day without harm . Follow us on LinkedIn and Twitter @JSABuilder, where we tweet about Health and Safety, post Safety tips, and provide updates on current Health and Safety topics. We also highly recommend that you try one of our other top safety tools at today, where our database-driven Lockout Tagout tool is currently available for a FREE 30-day trial, which will allow you to manage your lock out tag out program from start to finish. Easily enter your workers, equipment and procedures to build an entire LOTO program . Save time and money using LOTOBuilder and help your workers to work safe.

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