13 PCS Metric M35 Cobalt Steel Twist Drill Bit Set HSS Extremely Heat Resistant with Straight Shank to Cut Through Hard Metals Like A Hot Knife Through Butter,Such as Stainless Steel,Titanium Alloy

I've used these several times to drill out rusted rotor screws and works great!

The drill bits are good quality for the price the case however is junk and was broken on arrival. I have been using these bits quite regularly for a few months now, and they seem to be holding up well. Most of what I've been drilling is PCB boards and plastic with a small amount of thin metal.

Only reason I didn't give it five stars for durability or longevity is that I haven't had it long, and have used it only once. Given how it performed when I used it, though, I don't anticipate anything but more of the same; nice 'bite' into the aluminum plate, clean hole walls, even swarf curls from each gullet, so the flukes are cutting evenly, which means the tip is ground accurately and not cutting one-sided. These will be seeing frequent use!

quality appears to be good.

Arrived quickly and are very sharp, work well in a pin vise for 3D prints and minis.

I needed to drill out a broken-off 12mm hardened bolt in close quarters on my Honda Odyssey, and bought these hoping they were really hard cobalt steel and would not wander excessively without a center punch. These were exactly what I needed; I was able to center the drill and keep it there in the center of the bolt despite the awkward position, while the drill worked its way into the hardened M10.x bolt that I was so worried about. That one use alone made this purchase worthwhile, and now I have a whole set of these to use when I need something more than the junk drill bits sold at our local home supply store.

Amazing how the strange metric sizes like 4.8 are the exact same as a standard sae set.

Works

I drilled through bed rail with these bits, that material is murder on regular HSS bits. That said, I only got less than 2 dozen holes before I had to sharpen the bits. All those holes worked absolutely flawlessly, though: good spiral swarf coming off. Excellent bits. Now I need to sharpen them up on the grinder. But compared to the regular HSS bits, that just wouldn't even touch this metal. Even aluminum oxide bits, took 4 of them to drill a single hole, and that's 1/8" diameter in 0.10" thick metal: yes, it's that bad. It's cheap nasty metal, but look how indestructible it is. It takes cobalt bits to cut it (or else, just go really, really slow, with very sharp bits. That's another way to do it. Also, you cannot cut it with power tools. Has to be hacksaw. If you heat up the metal AT ALL then it gets very very resistant to any further work. Slow & cool is the only way.)

Bought these and they are crap.HSS..? I tried to drill through 3/8” aluminum. The bits actually bent in half. Thinking it was a one off… I tried the next size up. Also bent in half.Thinking the bit got to hot, I tried my Mastercraft, (Canadian tire) bit and it did the original job plus 6 more holes in the same plate.Compared to the Mastercard bit, these were garbage. !!!Tossed them in the garbage bin or I would have a picture for you…Don’t buy

Nice and sharp , seem to work very well, I only use them for certain types of drilling where i need a nice clean cut. I use my cheaper drill bits for run of the mill drill work.

Good bits for the price

The bits are very sharp and cut-in very easily. I don't know how long they will last but so far I am very pleased.