saw blades

Quoted text begins.sharpening the diamond saw blades
End of quote.

John,

I wish I was able to offer expert advice about diamond blades. I guess if I was
an expert, I would never misuse blades, and they would never need dressing.

Dressing or sharpening means exposing the diamonds from the matrix. Overheating
makes the diamonds shatter or fall out, so you're trying to cut stone just with
the matrix. This is called glazing, that is, the periphery of the blade is
smooth and glazed. Normally, a diamond blade feels rough around the rim, but a
glazed blade feels smooth (and hot!). Dressing a wet blade requires cutting
through abrasive material like sandstone or concrete, wearing away the matrix
and exposing the diamonds again.

Sometimes a dry blade can get hot just in one or more spots, you can see a burnt
spot on the rim. This glazed section bumps over the stone with each revolution,
and gradually gets worse. I find the best way to dress a dry blade that is
vibrating badly is to 'wipe' the blade across a concrete block while it is
running. That is, move the angle grinder in a sideways arc so the rim gently
contacts the concrete surface. Sandstone is too soft for this, the blade seems
to dig in too much. Dressing a dry blade makes plenty of dust, so it's best done
outside wearing the usual protective equipment (thanks, Bill!)

Of course, dressing is wasteful of your blade, but it's best to keep your blade
cutting effectively. If you find you have to dress your blade often, then you're
probably using the wrong blade for your material.

Where I work, we have a bridge saw set up for training. I use a granite blade
for all materials, cutting sandstone, granite and marble. Cutting different
materials with the same blade keeps the blade sharp, besides it is time
consuming to change a blade, and expensive to keep 3 different blades.

I recently read about Dr H Tracy Hall and his synthesis of diamonds:
http://www.htracyhall.org/History/bio.htm

Simon