SUBJECT: Bench and Pedestal Mounted Abrasive Wheel Safety

The Occupational Safety and Health Administration (OSHA) requires various safeguards to reduce hazards associated with bench and pedestal mounted abrasive grinders. The below listed safeguards are numerous but have all been established to reduce the chance of wheel breakage and resultant (sometimes fatal) injuries.
  1. A safety guard shall be installed over the wheel and cover the spindle end, flange and nut projections. The maximum guard opening is 90 degrees and the maximum opening from horizontal is 65 degrees. The maximum opening of the tongue guard shall not exceed 1/4 inch.
  2. The tool rest must be securely fastened and adjusted to 1/8 inch from the wheel.
  3. Eye shield protection must be installed and maintained in a condition which allows for viewing of work through the shield.
  4. The grinder base must be anchored for stability.
  5. Inspect the spindle speed on the machine and make sure it does not exceed the maximum operating speed marked on the wheel.
  6. As described below, ring test wheels prior to installation.
    • The wheel shall be dry and free of sawdust when applying the ring test, otherwise the sound will be deadened. In addition, organic bound wheels do not emit the same clear metallic ring as do vitrified and silicate wheels.
    • Wheels should be tapped gently with a light nonmetallic implement, such as the handle of a screwdriver for light wheels, or a wooden mallet for heavier wheels.
    • "Tap" wheels about 45 degrees each side of the vertical centerline and about 1 or 2 inches from the outer edge as indicated in figure 2 and 3. Then rotate the wheel 45 degrees and repeat the test. A sound and undamaged wheel will give a clear metallic tone. If cracked their will be a dead sound and not a clear ring. Do not use cracked.
  7. Replace wheels that are not flat or free of foreign matter.
  8. Wear safety glasses or face shield during use of grinder.

Guard exposure angles and various other safeguard design criteria are different for abrasive grinders other than bench and pedestal mounted units.