Cobalt Drill Bit Set, 115Pcs M35 High Speed Steel Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics, with Metal Index Storage Box

I had a use case where a machine screw had broken off in a location that wasn't easy to access. I decided versus pulling the piece of equipment apart to improve access, I'd spend the money on a set of these with the hopes it would catch as I was drilling out the broken off screw. The screw broke during installation, so I wasn't worried about rust or anything like that, and the roll of the dice paid off. As I slowly increased the size of the bits, one finally caught and backed it out. I replaced the machine screw with a new one and job done. This set saved me about an hour of disassembly and for me, that made the set worth the price. I don't know long-term how they'll hold up, but for me, these will be used infrequently and as I mentioned, they've already paid for themselves, so future use is just money in the bank. The case is nice and the quality seems good, so no regrets here.

I had to drill out a frozen bolt, hard steel, wore out two bits but it managed to cut through, dulled several of my existing bits first.

I just received this and drill a total of 5 hole with all size. The smaller one broke instantly. Not sturdy but the bigger one seem to do the job but not as good as my other drill.If you looking for nice reliable bit these are not the one. It work on some applications but I don't think they will last long for multiple uses6/17/25 updateCustomer is superb. Even though the small drill bit wasn't good n it broke the bigger one did the job. They reach out and refunded me to make it right. OK drill and good customer service

High Quality

Nice set. Would be 5 star rating except I wish they had the flat side on the shank to differentiate them from my other bits. With proper lubricant, speed and pressure the bit I used went through stainless steel no problem. Would buy again. GREAT PRICE TOO!

I tried using the drill bits to go through stainless steel, did not do the job. I wasn’t having any success with my other drill bits either, so maybe the material I was working is just really hard.

Convenient set with a compact holder

Muy bueno