Pedestal grinder maintenance - Ring test

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Grinding wheels can be extremely dangerous. If you over-rev the wheel, and it has microscopic defects or cracks, it may shatter, sending shrapnel everywhere and possibly injuring you or a co-worker. Here’s what you need to know about the proper care and maintenance of your grinding wheels. Despite its long history, its extreme precision and its ability to machine even the hardest of metals to a glasslike finish, grinding remains a bit of a black art. With a host of variables that include grit size, bond and the abrasive itself, it can be challenging to find the optimum wheel for a given grinding application, let alone use and care for it properly. Fortunately, there are loads of people offering free advice on the subject—the experts cited in this article among them—all of whom have plenty to say about this last part: the care and handling of grinding wheels.

How to Perform the Ring Test

Just like fine china, an undamaged wheel will ring when tapped in a certain way. Grinding experts call this the “ring test,” and it’s something that should be done before mounting any wheel to an arbor:

The wheel should be dry and free of any foreign material. Visually inspect it for cracks, chips and other damage. Suspend the wheel on a pin or hangar. Large wheels can be stood on edge on a clean, hard surface. Using a light, non-metallic implement (a screwdriver handle does a fine job), gently tap the wheel 1 to 2 inches from the periphery and 45 degrees to either side of the wheel’s vertical centreline. Rotate the wheel 45 degrees and test again. Each tap should produce a clear ringing sound like that of a bell. Cracked wheels will emanate a dull thud and should be disposed of immediately.