IRWIN 63137 Cobalt Alloy Steel Fractional Straight Shank Jobber Length Metal Index Drill Bit Set, 15-Piece

Good quality drill bits, handy for removal of a snapped bolt in a car engine, being a left handed thread. Cobalt can be brittle, but with care it did the job nicely for me and I used a drilling and cutting oil.

Good quality sharp drill bits made in the USA. They did the job really well.

Good quality

Used 4 sizes, including the smallest and the largest and so far, they are cutting through thick metal like butter. I remember such drill bits when I was young, before the markets got saturated with cheap bits that don't last or don't even do the job. These are remarkably well made and are worth the money. Just remember to use oil to cool them while drilling.

I purchased these cobalt bits based on reviews, and had a hardened steel plate to drill. Already have tons of high end bits but wanted to splurge , the extra cost of these bits are not worth it at all, broke to bits immediately on a press drill, and even the ones that did not break , did not even penetrate the steel, very disappointed and I would not buy these again, I can’t understand how the reviews quoted them so good, and yes I know about but lubricant and drill bit speed. Wish I could get my money back and buy 3 sets of regular bits...do not recommend