IRWIN Drill Bit Set, M35 Cobalt Alloy Steel Steel, 29-Piece (3018002)

Spend the money they are worth it. Bought to drill stainless steel. It is best to start with a much smaller bit than necessary and work your way up to the hole size you need. These are def heavy duty.

Works great

i use these all the time they hold up well , i have bought several through the years and always good quality they work perfect on hard steel ,i would never buy cheap bits again ,well worth the money

Great set and these drill bits are the best I've used (baring specialty bits that are as much as this whole set). We were recently drilling through some thick metal to attach some new wooden slats to a cart and I was using one of these bits to drill with. After about 40 holes (with no cutting oil mind you) and not taking much of a break between, I did finally break one. We needed to drill roughly 50 holes. Went to the hardware store and they didn't have any of these in stock, just the lower grade ones. Titanium or something, I don't' remember. Anyway, broke 5 bits in the last 10 holes. Basically, these are way better than the alternatives.The reason for 4 stars it that the case is kind of terrible. The smallest drill bit constantly falls out and the whole thing is soooooo chintzy. It has that feel like the execs were sitting around and said "How can we make it SEEM like it's high quality and still make it as cheap as possible?"Barring the lousy case, you'd be hard pressed to find a better set of bits for this low a price. I can't recommend it enough.

Highly recommend for hardened steel

This was my first set of higher quality drill bits & they have worked amazingly well so far. After years of cheap sets that go dull after 1-2 uses these have been a game changer. They stay sharp & cut into steel very well. Have used the set to drill out bolts that I would have never even attempted in the past. I'm sure there are higher quality sets out there for big money but for the price these do very very well. Highly recommend

I make no pretense to being a professional machinist, et cetera. In truth, pre-MBA, I was a scientist via mathematics. So, if your metric for relevance is related-professional-experience, give my review a skip. Indeed, I spent four years at a posh, New England prep-school, so, I even missed learning experiences such as "shop classes," ... among other things.Prior to these Irwin cobalt bits, I was of the, "crank up the (rotational) speed and hope for the best," school of metal drilling. Stupid. Watching (literally) these bits work provided a priceless, hands-on lesson in applied physics and physical metallurgy. Slow the rotational speed down (W-A-Y down), judiciously increase pressure (id est, PSI-loading), and watch ever longer spirals emanate from your successive drillings. Conversely, crank up the rotational speed, cook the bits, and complain about poor Chinese product molecular composition, drill bit fabrication, or, for something utterly inane, the packaging. I "cooked" the Irwin cobalt 1/4-inch bit and split the 3/8-inch. Fortunately, those two were the extent of my tuition costs.Despite the "handicaps" enumerated in the first paragraph, over the last twenty-five years, I have built eighteen proper -- with foundations and electrified (as in, "electrons," thank you) -- buildings, worked on heavy equipment (through 40-ton 'dozer), and burnt "miles" of welds. So, while I'm not "professionally" credentialed in the machining/building trades, I had been sought out to "fix" mechanical/"mechanical" problems of many folk who were. I was far from an utter rookie when the Irwin cobalts arrived; I am sure glad that they did. I'll buy more if and as needed.

The bits are very good, very sharp. The case is terrible. Hard to open, hard to close. The top does not match the bottom. I would buy again only for the bits. I am looking for a good case. This one should be replaced by a good one. Someone in quality control is not doing their job.