02 Jun Grinders

Grinders

Grinders are powerful tools used to cut, shape, sharpen, clean, polish, and finish metal and other materials. Bench grinders are typically mounted to a workbench, while pedestal grinders are secured to a floor-mounted pedestal. Portable grinders are designed to be handheld and must be used according to the manufacturer’s instructions.

Grinding operations can expose employees to wheel breakage, flying particles, sparks, entanglement, cuts, burns, electrical hazards, noise, and hazardous dust. Proper wheel selection, guarding, inspection, and operating technique are essential.

Personal Protective Equipment

Wear PPE appropriate for the grinding operation and material being worked.

• Wear safety glasses with side protection.
• Wear a face shield over safety glasses or goggles when exposed to flying particles, fragments, or sparks. A face shield does not replace primary eye protection.
• Wear hearing protection when required by noise exposure.
• Wear appropriate protective clothing to protect against sparks and hot particles.
• Secure long hair and avoid loose clothing, jewelry, lanyards, or other items that could become caught in rotating equipment.
• Do not wear loose-fitting gloves around rotating equipment where they could become caught or entangled. Evaluate glove use based on the task and manufacturer’s instructions.
• Use respiratory protection only when required by the hazard assessment and the company’s Respiratory Protection Program.

Inspect Before Use

Inspect the grinder and abrasive wheel before each use. Do not operate equipment that is damaged, improperly guarded, or functioning abnormally.

Check for:

• Cracked, chipped, damaged, or excessively worn wheels.
• Missing or damaged guards.
• Loose components or mounting hardware.
• Damaged electrical cords, plugs, or switches.
• Improperly adjusted work rests or tongue guards.
• Excessive vibration.
• Incorrect wheel type or size.
• Wheel speed ratings that are incompatible with the grinder.

The maximum operating speed marked on the wheel must never be less than the operating speed of the grinder.

Remove defective equipment from service and report it to your supervisor.

Abrasive Wheel Inspection and Ring Testing

Before mounting an abrasive wheel, inspect it closely for damage. Where applicable, perform the manufacturer’s recommended ring test to identify cracks or defects.

A ring test is not appropriate for every type or size of abrasive wheel, so employees must follow the wheel manufacturer’s instructions.

When installing a wheel:

• Verify that it is the correct size and type for the grinder and material.
• Confirm its maximum rated speed is adequate for the grinder.
• Use the proper flanges, blotters, and mounting hardware when required.
• Do not force a wheel onto the spindle.
• Do not overtighten the spindle nut.
• Ensure guards are properly installed before operation.

After installing a new wheel, stand clear of the wheel’s plane and allow the grinder to reach operating speed before beginning work. Stop the grinder immediately if unusual vibration, noise, or other abnormal operation occurs.

Guarding and Clearances

Machine guarding must remain properly installed and adjusted during operation.

For typical bench and pedestal grinders:

• The work rest must be adjusted to within 1/8 inch of the wheel.
• The adjustable tongue or upper peripheral guard must be within 1/4 inch of the wheel.
• Adjustments must be made only when the grinder is stopped and the wheel has completely stopped rotating.
• Readjust the guards as the wheel wears.
• Replace the wheel when required clearances can no longer be safely maintained.

Never remove or bypass a grinder guard to make a job easier.

Safe Grinding Practices

When operating a grinder:

• Make sure guards and shields are properly positioned.
• Stand to one side when starting a bench or pedestal grinder and allow it to reach full operating speed.
• Never start the grinder with the workpiece touching the wheel.
• Hold the workpiece securely and maintain control throughout the operation.
• Apply material gradually without excessive pressure.
• Keep hands and fingers away from the rotating wheel.
• Do not grind on the side of a wheel unless the wheel is specifically designed for side grinding.
• Do not force the wheel or attempt to make excessively heavy cuts.
• Do not leave an operating grinder unattended.
• Allow the wheel to stop naturally; never attempt to stop it with your hand or another object.

Sparks should be directed away from employees, combustible materials, flammable liquids, gas cylinders, electrical equipment, and other ignition hazards.

Dust and Material Hazards

Grinding can generate hazardous dusts, fumes, and particles. Know what material you are grinding before beginning work.

Certain materials and coatings may contain silica, lead, chromium, cadmium, or other hazardous substances requiring additional controls. Use appropriate ventilation, local exhaust, dust collection, or other controls as required.

Some combustible metals—including aluminum and magnesium—can create combustible or explosive dust hazards under certain conditions. Do not grind these or other combustible metals unless the equipment, dust collection system, and work practices are specifically suitable for the material.

Never use the same dust collection system for incompatible materials when doing so could create a fire or explosion hazard.

Housekeeping and Fire Prevention

Grinding debris, metal particles, and dust can create slip, fire, and exposure hazards.

• Keep the area around the grinder clean.
• Remove accumulated dust and debris using appropriate methods.
• Keep combustible materials away from sparks.
• Do not allow grinding sparks to enter containers, drains, pits, or areas containing flammable materials or vapors.
• Follow applicable hot-work requirements when grinding creates a fire hazard.
• Maintain appropriate fire-extinguishing equipment when required.

Remember

Inspect the grinder and wheel, use the correct wheel, maintain required guards and clearances, and wear appropriate eye and face protection. Never use a damaged wheel or grinder, and never modify equipment or remove guards to get the job done faster.