i am semi serious...i have questions first...
would i be grinding freehand?
by the term perforation, are you talking about the hole?
what's with the brass tubing?
and 120 grit silicone carbide abrasive? is that sander or drill bit?
5 hrs to drill......damn dude. what speed is the drill on? i have a big ol delta.....(not sure of the lowest setting, but i can look)
Yes, freehand with gloves on.
Perforation = hole.
The "hole" you are drilling is not a hole. Ever install a lock in a door? You cut out a plug, you don't drill the whole thing. Same with the tubing. The brass tube is your "drill bit". It catches the silicone carbide abrasive and you slowly abrade your way through. You can't simply drill PW with any kind of regular drill bit.
The drill press (old Delta) is on the slowest speed. You sprinkle some abrasive on the PW which is in a jig of sorts, give it a shot of water, then lower the brass tubing until it abrades. Silicone carbide will wear out quickly. Dump out the old, put in some new and go again.
You are abrading a hole, not drilling, which is why it takes so long. You end up with a plug and a perfectly smooth straight perforation. I'll show you some.
I'll gather up some pics and take some new ones and show you how I do it. Stay tuned.
Here's another quartzite bannerstone. Before and after. I get my quartzite at the lake a couple miles from here. You'd never guess those ugly rocks would polish up so nice. Gary