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

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.

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.

They deserve the good ratings they are receiving and I could have marked a star down for I had with issue with the case. It is a nicely designed case if you are not old and have fat fingers so I can't down grade there rating because I am old with fat fingers. I used the 1mm bit and in replacing it in the case, I let go of it before it was in the bottom hole. So it dropped down between the bit racks. The only way to retrieve it is to disassemble the case. It is designed not to come apart. In their desire to make a product withstand normal wear and tare, they melt over the ends of the pivot pins so they can't come out of the holes in the case. Not quite true, I could pry them out but worried the whole time I would break one as. the melted pivot ends up with different diameters.There are two solutions to this problem.. The easiest one it just be carful when you are replacing the small bits and don't let go of it until you are sure it is in the bottom hole. The second one never excites a manufacturer, modify your pivot points tooling. Add a sphere to the end just slightly larger than the mating hole. This allows for disassembly. You would save several seconds of labor by not melting the ends over and it would always be the same fit for removal. Probably the labor savings wouldn't cover the tool change cost. Well maybe it would if your ROI is 50 or 60 years.

8% Cobalt is the way to go

1. Be careful when handling these bits. They are sharp.2. I am working on a stainless steel control panel. I had work hardened several holes (forgot that stainless steel likes low speeds and lots of oil). Pulled out one of these new bits and it cut right through the virgin panel with zero problems, using either engine oil or WD-40 as lubricant. I don't have a drill press, but my 18 volt Milwaukee drill seemed to work well with them, although you have to make sure to tighten down on the bit to keep it from spinning in the chuck.3. I started by holes using the 4 mm bit. A 1 mm bit is included, along with a 1.5 mm bit, but, seriously, these little bits are going to break if you don't use a drill press.

First off I NEVER leave reviews on products. This company is better than Snap-on and all the tool trucks on their warranty policy and I’ll tell you why.First of all, the bits are great! They have a great cutting action and cut through hardened steel like butter. They really are quality bits. However, they ARE 8% cobalt which makes them very brittle. Any bit that’s 8% cobalt is going to snap now and again especially when using the smaller sizes on hardened steel.The reason I say they are better than tool truck quality is that for one, they cut hardened steel like butter just like any Snap-on or Matco 8% cobalt bit will. The second reason is their warranty on the bits and their prompt customer service responses.I’m a professional mechanic and we tend to drill out a lot of broken off license plate bolts so we use the 3mm, 3.5mm, 4mm, 4.5mm and 5mm drill bits to gradually drill pilot holes into the broken off bolts and then re-tap the hole with the standard 6x1.0 tap that most cars have their license plate bolts threaded to. I first broke a 3mm, contacted the company, and they sent me a 5 piece kit of their 3mm bits for nothing! Now I recently broke a 5mm bit yesterday, I contacted Stroton again and they got back to me within 24 hours. I mentioned that I broke the 5mm bit now and explained to them that I love the cutting action of these bits and also mentioned that I use the 3mm to 5mm bits often for broken bolt removal. Instead of just sending me one 5mm bit to replace the bit I actually broke, they’re literally sending me a 5 pack of each size from 3mm to 5mm (including the half sizes) so if I break another bit I’ll have extras on hand!The tool trucks typically have a warranty on their bits, but they put a disclaimer in there that says they won’t replace ANY bit for free if it’s from a certain size down because they know they’ll crack easy at 8% cobalt and they don’t want to replace those smaller sized bits because they know people WILL break them. This company literally just sent me a boat load of bits to cover me just so in case I break another small one, I’ll have 4 more ready to go now in the event I snap another one! Their warranty policy is basically, “you break it, we’ll replace it”! GREATEST COMPANY AND BEST WARRANTY POLICY PERIOD!

Had two bolts to drill out broke two bits on the first bolt. Still have another bolt drilling in step up fashion smallest to largest.

SHARP