Metric M42 8% Cobalt Twist Drill Bits for Stainless Steel and Hard Metal(1.5mm-6.5mm/13pcs)

I don't normally stop to review products unless it's something I use quite a bit and have tried other brands of the same type of product. Well I've burned, dulled, busted, even horribly abused all sorts of drill bits. They all seem to be about equal pretty much across the board. Some maybe a little bit better in performance. Nothing that really stood out to brag about. Ok I picked up this inexpensive set (I was going say cheap set because the price is very reasonable for what you actually get). These fricken drill bits are absolutely worth every single cent I spent on them. So worth it that I'm out here looking for a large set that has both metric and standard in the M42 8% cobalt grade these are. If you peck drill with this set I don't doubt they will last a good long time. And the warranty is incredible. Lifetime replacement. No one can beat that. I'll have to say tho, I haven't had to contact them yet for getting any replaced if needed. Let's just hope that would be a smooth process as well. I'm hoping. But I gotta tell you, I'm pretty busy at the moment, but stopped just to write this because I'm actually out here looking for a larger set from Stroton as where these came from. They are everything the boast in advertising and then some. Goes thru steel like it's no big deal. But remember to peck drill so you don't over heat the bit. That goes for any drill bit out there. But if and when you get these and try them, you will not be disappointed. At least I'm not. But then again I am 57 years young. So I have a little bit of experience on how to actually use a drill bit properly. If you don't have much knowledge about drilling, remember one thing, peck drill. If you don't know what that means, look it up. You will get way better results and your bits will last twice as long if not more. I know one thing, I'll get more than twice the expected life out of these due to the fact that they perform incredibly well. Like they stand out better than the average norm. They got me as a loyal customer. I really like'm. You'd have to tear them out of my dead hands to gett'm from me. So don't even try. Buy your own. They're right here, where you're reading this review. Good luck, have fun and happy drilling.Now a message to the seller of these bits.... where are the large sets of these bits. I don't see any. If you have one send me. Link. If not, than you'd better get one quick before I begin testing other sellers that have larger sets.Thanks for the bit. Good sht for real...!!!

Drilled several holes through heavy i-beam and did not dull a bit. Highly recommend it for your project and the higher cobalt content (8%) was worth the extra price. Used cutting gel and 1/4" pilot hole, powered by 1/2" electric drill.

This STROTON metric drill index is definitely inexpensive and seemingly decent enough quality for the average home shop. Drill bits are consumable items, thus the more common size "go-to" bits wear out soonest, rendering the remaining bits in the set somewhat irrelevant. Buy a quality bit sharpener to extend the working life of your drill index purchase.I've used just six large bits of the nineteen in this STROTON metric index, and I'll likely never use the remaining bits. I've plunged thru various materials: PVC, acrylic, ten-ply baltic birch, MDF, oak-cherry-walnut-pine, aluminum, mild steel and hardened steel. The bits cut thru the synthetic materials like butter. Prior to drilling metal, I sharpened the desired bit (using a Drill Doctor) beforehand, and it thru-cut flawlessly. Sharpening destroys the three-step edge, of course, which is gimmicky anyway.My lone grip with this STROTON metric index is the plastic case and tool holder. STROTON typically ships their drill indexes in a stout, decent quality metal case. Dunno why they skimped on the case for this consumer-grade drill index, but they clearly did.

Searching for a good drill bit I found these that are made with Cobalt in them. I tried my bits at home and realized they just weren't cutting. I saw all of the great comments and gave these a try. They worked. The only thing is yes they can break and will break if you bend them or work them really hard. I used tap lubricant but I did not know that you don't want the bit to heat up too much because it shortens the lifespan. I was using this for something I should have used a saw to cut. I wanted to drill out a screw. This made it possible. I broke most of the bits but I got the job done. Look at the photo I attached that shows how the metal shredded off like grated cheese at low speed using a new sharp bit. It was so cool I had to take a photo to share. You see the hole in the screw and under it you see shreds of metal that fell below.

This is a decent set of M42 bits at a GREAT PRICE. The VALUE is outstanding. Drill at appropiate speed, with cutting fluid on a DRILL PRESS and they should last a while for DIY use. M42 bits are very hard, but brittle, and are best used in a drill press. I found that one of the bits had an imperfect cutting edge and contacted Stroton's customer service as described in the instructions. They responded within 12 hours, communication was professional, and they replaced the bit within one day shipped from Amazon. Now THAT is what I call great customer service. Needless to say that I bought some other drill bits from them and they are still going strong. Buy with confidence!

Surprisingly work very good and haven’t deteriorated over the past year or so.

I bought this set a little over a year ago to support rivetnut installations and to enlarge some holes on tie bracket flange. Going through carbon steel I have had no issues at all, good solid drill bits. However, both times I have used them on stainless it has been a painful experience. The first time was 100% my fault, I didn't have enough cutting fluid. The next time, with cutting fluid to spare and lowering the drill speed, the tips dulled on the first hole and got progressively worse with each follow on hole. For additional context this was 2.5-3.5mm thick 300 series stainless steel, with an existing 7mm hole I was enlarging to 7.5-8.5mm depending on the intended location. It wasn't even a full drill out nor was it notably thick. These should have been easy cuts but were more than this set could handle.