Grinding wheels have a finite life and over time they wear down or become damaged due to misuse. In many ways, they are very similar to other wearable shop parts, such as end mills and drills. The proper installation of grinding wheels is crucial to the safety of those who use this machine to deburr parts. In order to install grinding wheels properly, you must make sure that the wheel you use is of the proper size for the bench grinder you are using.
Inspect the wheel to be installed visually before attaching it to the spindle. Look for obvious cracks and other marks on the surface that may be hiding cracks or divots, which will make using the grinding wheel dangerous as well as difficult. Make sure the wheel is in good shape before proceeding to installation.
Suspend the wheel by inserting your index finger in the spindle hole. Lightly tap it with the handle of a screwdriver to listen for its resonance. Cracked wheels will have a short sustain, while a wheel in good shape will ring out for quite some time. The pitch has less to do with the wheel's condition; larger wheels will often have deeper tones than smaller ones, but cracked wheels will be obvious.
Inspect the inner flange to make sure it is secured properly. Inner flanges may be permanently attached or attached with a key that will keep it in place. The key is a nub that sits in a slot to keep the flange from spinning on its own. This inner flange should not be loose. If it is, you may have to reattach it or adjust the key way in its slot.
Slide the grinding wheel on the spindle. Make sure it is a snug fit to prevent the wheel from coming loose. If the gap is more than 0.002 inch, use a different wheel that fits better. Try to wiggle the grinding wheel to make sure it is snugly fit and there is no play.
Place the outer flange on the spindle and place the retention nut on the threaded spindle end. Tighten the nut to prevent the grinding wheel from coming loose. The flange edges should be touching the paper-covered inner area of the wheel. This paper prevents the flange from damaging the grinding wheel. If there is no paper, place some in this area. It gives the bearing edges of the flanges a better grip.