Bench Grinder Safety

Risk Assessment

All machine safeguarding should start with a risk assessments for the specific task, application, and environment. A great place to start that assessment is with consideration of OSHA 1910.212(a)(1):

“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.” [OSHA 1910.212(a)(1), General requirements for all machines.]

Having said that, risk assessments for standard shop tools share many similarities and the discussion below will help to identify hazards and remediation strategies.

Most Significant Bench Grinder Hazards

The most significant bench grinder hazards are:

  1. Shrapnel From a Wheel Explosion

    An under-rated, worn, damaged, or clogged grinding wheel can fracture and explode. This is a severe hazard and often results in operator fatality.

  2. Getting Caught In The Wheel Housing

    Operator clothing, tools, work pieces, and appendages can be drawn into the wheel housing. This is a severe hazard and often results in amputation and/or severe lacerations.

  3. Contact with Grinding Disc

    An operator may come into brief contact with the grinding disc, causing abrasions and/or lacerations.

  4. Flying chips, sparks, and/or coolant

    Flying chips, sparks, parts of the grinding wheel, and other debris regularly exit bench grinders at high speeds and can cause irritation, burns, and severe eye injury.

often unconsidered risks

Many EHS experts focus their risk assessment on limiting operator exposure to these hazards during a grinding operation but fail to consider the greater context of the operation. One must also consider the time before and after the intended operation. There are two significant exposures to consider:

  1. Silent But Deadly Coasting

    Bench grinders are notorious for exceedingly long spin-down times between 2 and 4 minutes. During this time, a well tuned grinder offers no auditory or visual cues that it is still spinning. All of the aforementioned hazards are still present during this coast-down time and the risk is multiplied because subsequent operators and other nearby employees are not conscious of the hazard and therefore at greater risk for injury. For this reason, a coasting grinder is considered a point-of-operation hazard under OSHA 1910.212(a)(1) and it must be mitigated with a braking system.

  2. Visual Aides & Realistic Expectations

The best way to prevent getting caught in the wheel housing and to limit the severity of a wheel explosion is to regularly measure and adjust work rests and tongue guards to meet OSHA requirements. With work rest angle adjustments and the the variability of worn wheel diameters as everyday variables, this is a verification that should happen each time you step up to a grinder. However, an operator’s visual assessment of these spacings is highly variable and most don’t take the time to find a measuring device. That leaves them at risk.

MItigation strategies

Mitigation Legend
Mitigation strategies focused on prevention are coded green.
Mitigation strategies focused on lessening the severity of an incident are coded red.
For items that contribute to both prevention and lessen the severity of incidents, the more pessimistic coding is shown.

Bench Grinder Safeguards and Mitigation Strategies

Hazard Activity Mitigation
Shrapnel from a wheel explosion.

• During grinding
• Before/after grinding

• Develop procedures for visually inspecting and ring testing new grinding wheels before they are mounted  [OSHA 1910.215].
• Install a tethered grinder gauge and develop procedures to verify rest and tongue guard spacing [OSHA 1910.215].
Getting Caught In The Wheel Housing • During grinding
• Before/after grinding

• Bring the grinding wheel to a controlled stop before the operator leaves the machine by installing a motor brake.
• Install anti-restart protection [1910.213(b)(3].
• Install a tethered grinder gauge and develop procedures to verify rest and tongue guard spacing [OSHA 1910.215].
• Approved lockout/tagout means and procedures [OSHA 1910.147].

• Install an emergency stop button [NFPA 79].

Contact with Grinding Disc • During grinding
• Before/after grinding

• Bring the grinding wheel to a controlled stop before the operator leaves the machine by installing a motor brake.
• Install anti-restart protection [OSHA 1910.213(b)(3].
• Approved lockout/tagout means and procedures [OSHA 1910.147].

• Install an emergency stop button [NFPA 79].

Flying chips, sparks, and/or coolant • During grinding
• Before/after grinding

• Install a tethered grinder gauge and develop procedures to verify rest and tongue guard spacing [OSHA 1910.215].
• Provide and wear PPE.

The table above focuses on the less commonly known mitigation strategies and does not include details about chip guards, shields, PPE, equipment inspections, or scheduled maintenance.

An All-In-One Solution

The MAKESafe Power Tool Brake is a plug-and-play braking solution for grinders that also includes anti-restart and emergency stop. All you have to do is plug it in, perform a calibration that takes less than five minutes, and you’ve added multiple machine safeguards to your bench grinder. See a demonstration video and device specifications for more information.

Other Bench Grinder Requirements

After the risk assessment is complete, be sure that your planned safeguards also comply with these explicit requirements.

  • Side guards must cover the spindle, nut and flange and 75% of the wheel diameter [OSHA 215(a)(2)].

  • The maximum RPM rating of each abrasive wheel must be compatible with the RPM rating of the grinder motor [OSHA 215(d)(1)].

  • Various maintenance, inspection, and electrical safety requirements: OSHA 215(d)(1), 22(a), 94(b)(2), 133(a)(1), 212(b), 304(g)(5), 305(g)(1)(iv)(A), 305(j)(4)(vi)

More Information On Bench Grinder Safety

Scope: The information above is intended for standard bench or pedestal grinders under 3HP.