I drill jars & vases by the thousands with almost 4 years experience. I purchased a very expensive diamond drill bit from Advantage Drills, Inc. due to the claimed better performance and longer life. I've always been able to drill up to 300 times with one, cheap $18 diamond bit made in China.
With Advantage Drills, Inc's $150 bit I couldn't even get to 10 drilling's!!! It just self destructed into pieces! The first one, which they replaced with the one I just described, started crumbling on its second drilling! Remember that I accomplished up to 300 uses with a cheap, $18 Chinese bit many, many times in the past 4 years. I sent everything back to Randy, the claimed owner, who proceeded to cuss me out when I called him with a fervor rarely heard from a seasoned sailor!!
Randy told me to go f*** my own mother! This guy is really out of control and, as you can surmise from his offensive attitude, he was completely unwilling to refund any money despite this trash product's defective design. He defends this garbage drill bit despite the obvious. Never have I been subjected to such vile and abusive verbal treatment - never!!!
Advantage Drills, Inc. should be avoided like the plague! If your purchased product fails due to defective design you will probably get another one likely to be identically defective - not your money back! And, if you dare suggest that it is his product which is at fault, and not you, Randy will possibly treat you to an overwhelming onslaught of disgusting verbal sewage.