There are several elements in maintaining one of the work horses of many glass studios.
Ensure there is enough water to supply the pump or sponge that wets the grinding bit before starting any grinding. Too little water reaching the bit, fails to lubricate the diamonds and keep the glass cool. If you are getting a white paste or a powder on or near the glass, you need to increase the water supply.
Empty the reservoir daily. This keeps the water from producing a smell, and allows you to clear the glass residue from around the grinding bit.
If you are changing to a finer grit, it is important to change the water, clean the resevoir, and thoroughly clean the sponge each time you make that change. Otherwise, you risk bringing coarser grit to scratch the finer grinding surface.
You can also buy a additive for the water – often called a diamond coolant – which is intended to provide a kind of lubrication for the diamonds. This may extend the life of the bit a little.
Periodic removal of the bit and lubrication of the shaft should be part of the regular maintenance of the grinder. You should make sure that the socket for the grub screw is clear of glass residues before attempting to turn it. I do this by using a needle or other thin sharp object to clear out all the glass powder. When the socket is cleaned, I push the key into the socket very firmly and hold it there while turning. Prevention maintenance is to fill the socket with vaseline or thick grease after tightening the screw.
Inspect your bit carefully for smooth areas showing that the diamonds have been worn away. Also look for dents, and other irregularities on the surface, indicating that the bit is damaged. In these cases, the bit should be replaced.
Before putting the old or new grinder bit back, ensure the shaft is smooth and without corrosion. Then coat the shaft with Vaseline or a proprietary anti seize-compound. This will ease the removal of the bit later. If the shaft is corroded, use a strip of fine wet and dry sandpaper to shine the shaft.
Sometimes bits need to be dressed – removing protruding diamonds, or cleaning and exposing new ones on a worn bit. To dress the bit you can grind some scrap glass, brick, or use a dressing stone to lightly grind some of the abrasive material away. This can extend the life of the bit.
Adjustment of height
If your grinder bit is too low or too high the diamond surface will not grind the whole of the glass edge. This can lead to chipping of the surface of the glass at the edges.
A good practice is to start with the bit as high as possible to allow for differing thicknesses of glass. As high as possible is with the bottom of the diamonds just below the platform of the grinder. This will ensure that you can deal with varying thicknesses of glass without immediate adjustment. You can then reduce the height of the bit as it wears.