Metric M42 8% Cobalt Twist Drill Bits Set for Stainless Steel and Hard Metal (1mm-10mm/19pcs)

These drill bits are genuinely very good quality and have performed extremely well for me when drilling into a wide range of materials, particularly metals (excluding concrete and masonry, as expected). They cut cleanly, feel well made, and have clearly been designed with durability in mind. During normal use, I unfortunately had two bits break. I contacted Stroton more to inform them than to complain, fully expecting at most a replacement for the damaged items. Instead, they responded quickly, asked no awkward questions, and simply requested confirmation of my address so they could send out replacements. To my surprise — and genuine appreciation — they sent out an entire new set, not just the broken pieces. This level of customer care is rare these days and speaks volumes about the company’s integrity and confidence in their products. Mistakes or failures can happen with any tool, but how a company responds is what really matters. Stroton handled this perfectly: polite, efficient, generous, and hassle-free. The replacement is already on its way, and I couldn’t be more impressed. Excellent drill bits, but even better customer service. I wouldn’t hesitate to buy from Stroton again and would happily recommend them to others.

I purchased the cobolt drill bit set as i have dozens of drill bit sets but wanted a set of higher quality. As can be seen in the photo my cobolt set remains largely unused however, on using the 3.5 mm bit it snapped first use. I work private security overseas and so my time in the uk has been limited until now. It would be nice if Stroton were to honour their stated lifetime guarantee but am not holding out much hope but you never know. A good set of drill bits with the 3 step bit head design but very brittle.

The item was sold at a keen price and delivered in double-quick time. I ordered the Cobalt drill bits because, having read the description, I believed they would be a more resilient bit than the normal HSS type, and would do the job of drilling out the sheared stub of a fixing bolt. However, I used two of the new bits to try and drill a pilot hole in the end of the stub and both of them very quickly blunted and lost their cutting edge, making no impression on the stub (I am unable to say what type of steel the sheared bolt stub was manufactured from). In view of this, and previously having blunted and broken several HSS bits, I was forced to abandon trying to remove the stub and used the Cobalt bits to drill a new hole through the 2mm steel sheeting which was easily achieved. And so, although the Cobalt bits didn't perform as I had hoped, they do appear to be quite a sturdy product and easily able to deal with cutting through reasonable thickness, normal steel, without a problem. As a result of the above, I contacted the seller to request replacement of the two damaged bits under the terms of their warranty. They not only responded immediately but did more than I anticipated, sending me a full new set of drill bits, as well as giving me a full refund on those initially purchased! What more could anyone ask for? If that's not excellent customer service, I don't know what is!! I recommend the company highly.

Really good quality drill bits for hard stainless steel. I had been trying to drill stainless steel with normal HSS bits and it wasn’t doing anything. These bits drilled straight through it no issues. The swarf came off in big strands as the drill bits easily machined through the steel. Excellent.

Very sharp and strong

This is the worst bit of rubbish I’ve bought off of Amazon And I’ve bought a lot of Amazon which has been very good to start with. I was drilling through mild steel brackets I needed 12 quarter inch holes my drill was at low speed for the first pilot hole. It done two holes then gave up. as with the other two sizes, the same thing happened. So I went to Screwfix and paid £18 for three real Cobalt at different sizes and done the 12 holes perfect so I would like a refund please and I advise customers not to buy this rubbish. Kind regards TM Woods.

Good drill bits, took an M10 stainless 316 bolt no issues, as long as you know what to do with a drill! ;)

I have to say, I wasn’t expecting too much, but I needed some replacement 8% cobalt drills to take out a sheared off stainless bolt. These performed beautifully and the specially ground cutting edge allowed for less drift and thus more accuracy. These were very good value for money and did the job extremely well. Only tip, use either some lathe coolant or a good squirt or two of WD40. Don’t force the drill bit, keep steady pressure and allow the bit to cool a little if the job is quite big, especially on stainless. I was pleased and I think they were pretty good value for money.

Puedes hacer agujeros con facilidad en metales duros como inox 316

At first I was a bit discouraged as per instructions I was using low speed drilling. It was not going through stainless steel at all. Then I switched to high speed and this was when the drill started to made it through with ease! Just to mention here that bits (Titanium coated) from Canadian Tire were absolutely useless!!!! No sign of overheating, bits stayed sharp through at least 10 holes for my first project using these new drill bits. I hope it will continue for years to come. Added on November 28, 2025. This set is amazing! Drills through SS almost as through wood. I use drill press with medium speed. No overheating or strange noises. Just goes through at steady speed. Highly recommended!

Las compré para inoxidables y se soporta las cargas como todo con el uso prolongado van perdiendo filo pero dura bastante para su precio

Gostei As brocas são muito boas

Very good quality