zoser, on 01 December 2012 - 09:18 AM, said:
Try drilling granite with an ordinary 0.25 inch steel drill. See how long it lasts. Then imagine that's your copper and sand combination trying to drill a 2-3 inch diameter hole 2 feet deep.
You must've missed where I quoted the part about
steel, brass and copper used in conjunction with abrasive. Non-sintered core drills are made from ordinary steel. The type of abrasive makes little difference either. Quartz (IE: sand) is mohs 8. It'll cut anything mohs 8 or below, including itself.
Quote
Better still listen to the experts in the above video's; this is precisely what archaeology has lacked; specialist knowledge.
I've only made it half way through the second one as yet and so far all I'm hearing is dunn droning on about stuff totally outside his experience along with that other machinist and trading straw man assumptions with childress, who has no experience at all and can't even pronounce basalt right.
Edit: I did like that bit at about 14:20 though:
"Fairly close. obviously there are going to be some imperfections"
You don't say? So much for laser-like precision.
Edited by Oniomancer, 01 December 2012 - 07:46 PM.
"Apparently the Lemurians drank Schlitz." - Intrepid "Real People" reporter on finding a mysterious artifact in the depths of Mount Shasta.