How to Safely Mount Grinding Wheels
Customers often ask if they can mount several wheels onto a single arbor in sets. There are some grinding applications where it is common to use multiple wheels on a single spindle such as centerless, crank, and cam (bearing) grinding. Here are answers to some common questions.
Question: In applications with multiple wheels mounted on a single spindle without spacers, can we mix and match grinding wheels from different sets, different abrasive manufactures, different batches, etc.?
Answer: No, you cannot mix and match wheels from different sources. Multiple grinding wheels used in sets without spacers (for example many centerless applications) must be manufactured and marked for use as a multiple wheel set. Each wheel in “multiple wheel sets” has special tighter side and hole tolerances. The sides must be parallel to each other and the holes must be perpendicular to the side of the wheel. Also, the wheels are “trued” and “balanced” as a set.
Combining several grinding wheels and mounting them onto a single arbor when they are not designed and manufactured to be used as a “multiple wheel set” is dangerous for several reasons. The cross bending stresses applied to wheels with uneven sides and wheels with sides not perpendicular to the wheels' hole can break even the strongest wheel. Slippage problems, irregular faces, and balance problems may also occur. As ANSI B7.1 states, “When mounting wheels which have not been cemented together, or ones which do not utilize separate spacers, care must be exercised to use wheels specifically manufactured for that purpose.”
Question: What are the requirements for applications with multiple wheels mounted between spacers on a single spindle?
Answer: When multiple wheels are mounted between a single set of flanges using spacers (for example camshaft grinding) the user must follow ANSI requirements.
For spacers LESS than .050" thick ANSI B7.1 states, “Spacers less than .050" thick, used between wheels which are mounted between a single set of flanges, shall be equal in diameter to the flanges. They shall be made of low compressibility material such as brass or soft copper. Blotter material shall NOT be used in place of or in conjunction with thin spacers.”
For spacers GREATER than .050" thick ANSI B7.1 states, “Spacers thicker than .050" may be steel and spacers thicker than 3/8" shall be made of steel. When steel spacers are used, their diameter shall equal flange diameters, and the spacers shall be relieved so that bearing surfaces equal flange bearing surfaces. Blotters shall be used between spacers and wheels.”
Failing to follow these rules can lead to problems with wheel slippage and wheel breakage.
Question: We have several thin cut-off wheels and would like to mount them onto a single spindle to create a thicker Type 1 wheel. Is that safe?
Answer: No, that would be dangerous. If you need a cut-off wheel, purchase a cut-off wheel, and if you need a thick Type 1 wheel, order a thick Type 1 wheel. Do not use a grinding wheel in an application for which it was not designed.
Question: Is there a limit to how many wheels may be mounted on a single spindle or machine?
Answer: The spindle length and machine wheel guard are indicators of the size and number of wheels that can be safely mounted on a single spindle or machine.
Improper wheel mounting can cause wheel breakage, personal injury, and even death.
For additional information on this topic or if you need any other abrasive safety information, please review the Norton Product Safety page, ANSI, OSHA, and all literature provided by the abrasive wheel and machine manufacturer. You may also contact the Saint-Gobain Product Safety Department at (508) 795-2317, fax: (508) 795-5120, or contact your Saint-Gobain Abrasives, Inc. representative with any safety related questions