I was surprised these performed so well on my granite counter top considering the price! I thought I would go through all 5 bits but I successfully drilled through using only one bit. And it was sharp from start to finish!
I used plenty of water to lubricate, and took a few breaks to let the bit cool down.
The bit is having a hard time punching the hole
in my stainless steel kitchen sink. Gets real hot, real quick. I have to stop and let It cool. Taking forever.