I am trying to drill though a stainless 3/8" steel bolt (grade 6) on a poo l pump. How long should it take to go 1/2 inch? I think after an hour, I managed to get through 1/8 inch using oil as a lubricant. I am using a 1/4 Dewalt Cobolt bit from Lowls (listed for stainless steel). Is this better than the Irwin titanium bits? I have some diamond bits from Harbor Frei ght tools, but it seems as if the diamond dust was scraped off very quickly . Any suggestions on what else to do, i.e. take it to a mechanic who will cha rge $50 an hour. Are there any suggested drill bits made from industrial di amonds or are they overpriced?
- posted
8 years ago