Be sure that the proper length screws are used in attaching the abrasive disc to the steel mounting plate. The screws must not, repeat, must not, protrude through the mounting plate more than 3/8".
Prints of steel disc wheel mounting plates, furnished by the disc grinder manufacturers, show either 13/32" or 27/64" mounting holes with a 5/8" diameter counterbore leaving the critical web dimensions as listed below:
12" to 18" dia. discs
- 3/16" web, use 3/8"-16NC Cap Screws 1/2" long
20" to 26" dia. discs - 5/16" web, use Cap Screws 5/8" long
28" to 42" dia. discs - 7/16" web, use Cap Screws 3/4" long
Again, be sure that the proper length screws are used in attaching the abrasive to the steel mounting plate and that the screws have a flat bottom as shown below.
