On 02/17/2020 09:38 AM, Jim Joyce wrote:
n Mon, 17 Feb 2020 08:11:27 -0700, rbowman wrote:

On 02/16/2020 08:50 PM, wrote:
OK, what's the trick. This stuff just laughs at a Tap Con bit in a
hammer drill (the carbide tip ends up melting) and if you try to shoot
a tap con screw in it, you get a nail. It wipes out the threads. I
just bought some Bosch super bits ($10 a pop) and I am trying them
tomorrow. They say they will eat concrete with rebar in it.

Diamond drills and a lot of patience. Being able to use a drill press
helps but I doubt that's an option for you.
I've drilled various floor tiles, glass jars, ceramic vases, etc., with a
diamond bit and cool water for lubrication. I used low speed and light
pressure. Let the drill and bit do the work.

A company I worked for had a little side line in decorator quality lamps
made from Fukagawa porcelain vases. We sort of had tryouts to find women
that had the patience and light touch to drill them. The other problem
was convincing them if a $150 jug broke, well **** happens.

We used Delft too but that was a piece of cake compared to Fukagawa. The
Dutch called it porcelain but it really wasn't.