dremel bits....

[Don Dougan <dondougan@xxxxxxxx>]

Justin:

They will work fine - just remember to keep the pressure on the tool as
light as possible - allowing the speed and the diamonds to do the work.

The diamond abrasive bits made like yours are coated with a metal plating
to hole the diamond dust onto the tool shank.  Heat and friction from
heavy pressure will shorten the life of the plating, allowing the diamond
abrasive to be lost.  This is especially so in working the harder
varieties of marble (or granite, etc.).

Working under a water-drip (from a tin-can with a tiny hole punched it)
will cool and dramatically increase the life of the bits, though it will
make more mess to clean-up than the dust.  Another way of using water
(when working with a flex-shaft handpiece) is to work in a dishpan with
the current working-area of the workpiece barely submerged in water.
Caution should be used when working with electrical tools and water!

The really inexpensive sets are made with relatively soft steel shanks -
the shanks won't last long either - I have had a number of them break
 from metal-fatigue when working at high-speed (30,000 rpm), and the
little shaped tip goes flying through the air as a projectile - ie., wear
safety glasses.

Those caveats given, the diamond abrasive burs work great for both marble
and alabaster, and the price is hard to beat.  I find that the diamond
bur works best following preliminary 'rough' work by either the green
silicon-carbide mounted stones or the tungsten-carbide cutting burs (both
of which such as Dremel makes), rather than trying to do all the work
with just the diamond abrasive bits.

More expensive bits from industrial (or dental) suppliers will last
longer and come in a wider variety of shapes.  They are made much the
same way as the inexpensive ones, but the plating and the diamond dust is
a thicker coating, and the shanks are made with hardened tool-steel
(which will not as easily develop metal fatigue).

Good grinding to you;
Don