snip
On 3/13/17 9:57 AM, -MIKE- wrote:

As I stated in another reply, the jury is actually still out on this one.
I got caught up in all the controversy, hype, and all that I forgot why
I wanted these in the first place-- to drill through porcelain and
granite, because I was spending a small fortune on tile bits and the
drilling took too long.

My initial tests have been positive. I'm going to do a "simulated
install" scenario using the same bit to drill about 18-20 holes through
a porcelain tile which it not uncommon on a job installing grab bars in
one bathroom. I'll time the first hole, and the last and see how they
hold up.

It is not uncommon for me to go through 2-3 expensive store bought bits
to do this. Only the most expensive diamond "hole saw" bits are worth
their salt and even those take a LONG time to drill through porcelain,
because of all the surface area actually being cut. (Think of the
geometry of them.)


I use the cheap ($2-$3) diamond dust tipped hole saws all the time to
cut holes in glass/tile/ceramic (usually 1/2" to 1" diameter).

Never a problem, always goes fast. Of course I have the object submerged
in a pan of water and use my drill press.
Even after 100's of holes, the bits still cut fine.

When I did have to drill holes for a faucet on a finished shower, i held
a soaked sponge above the hole to keep the area flooded. It took longer
since I had to refill the sponge several times, but still the bit cut
cleanly and quick. For smaller holes (3/8") I always just used the
standard carbide bits with water.

The diamond hole saw bits also work wonderfully on stainless steel sink
cutouts.

-BR