Many people have used our products without incident by implementing safe usage practices as well as understanding the dangers of improper use.  Please carefully review the following information.

General Warning and Spindle Speeds

  • Select proper wheel for the type of material to be ground.
  • Lock wheel securely to spindle.
  • Dress wheel with a diamond dresser only.
  • Use only recommended wheels as on the label.
  • See ANSI  B7.1 and OSHA regulations regarding safety practices.
  • Be sure both wheel and belt guards are in place prior to starting grinder.
  • A set of pulleys are supplied with your unit which operates the spindle at speeds which give the proper peripheral speed for the grinding wheels furnished. These pulleys are numbered and a chart on the nameplate attached to the grinder gives the correct combination of pulleys to be used with wheels of various diameters.


Grinding generates dust. Most of the dusts generated when grinding are from the material being ground. Excessive dust inhalation may affect the breathing function. To avoid breathing impairment, always employ dust controls and/or protective measures appropriate to the materials being ground.

See Federal Hazard Communication Standard 29 CFR 1910.1200.


Grinders and grinding wheels improperly used are dangerous. Do not use wheels with a diameter larger than those specified. Do not use pulley combinations other than those specified. Comply with ANSI B7.1 and OSHA covering speeds, safety guards, flanges, mounting procedures, general operating rules, handling, storage, inspection and general machine conditions.


Themac does not guarantee the wheels for any particular application. All wheel type descriptions are only recommendations.  Some wheel testing should be done in order to determine the appropriate size and type for specific grinding requirements.

Grinding wheels are of a ceramic nature are brittle and easily damaged. The speeds at which they can be safely run are strictly limited. This limit is 5,500 to 6,000 feet per minute on the rim, or roughly a mile a minute. The larger the wheel, the lower the speed (i.e., a 5" wheel can be run at 4,500 RPM, a 12" wheel at 1,800 RPM and so on).

Please refer to the material safety data sheet for the composition of the grinding wheels by visiting the manufacturer's website for the latest safety information. The following list may contain outdated information:

More information on wheel sizes and no-load speeds.

The information found on this page is for reference only and it is recommended that you review ANSI B7.1 and OSHA conveying speeds, safety guards, flanges, mounting procedures, general operating rules, handling, storage, inspection, and general machine conditions.