Cobalt Drill Bit Set, 9/16" (4pcs) M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case,

This cobalt drill bit set performs really well on harder materials. The bits stay sharp and cut cleanly when used with proper speed and pressure. Sizes are accurate and the set covers most common needs. Used them for metal drilling and they handled the job without overheating or dulling quickly. Great value set for DIY or shop use and a nice upgrade from standard bits.

I cleared a stripped screw head using one of these bits and it took me less than 20 seconds. I had previously tried using several different extractors and none worked. One of these bits was literally the only way I could remove the screw. For note taking purposes, the screw belonged to a door knob and was also warped. I am happy with the quality of all of the drill bits. Mine came slightly lubricated with some kind of machine oil. The affordability of these cobalt drill bits is excellent and their performance is even better. The speed that I was able to remove the stripped screw with was amazing. I literally drilled into it and the lingering stuck knob literally fell off. If all else fails and you're trying to remove a stripped or warped screw, try using these bits to help you out.

I love a good drill bit set. There is something deeply satisfying about opening a fresh case of organized bits—it makes me feel like I can build a deck, fix the car, or at least hang a picture frame without putting 14 unnecessary holes in the drywall. This set is almost perfect. The Good: The case is sturdy and holds the bits tighter than I hold onto the thermostat setting in the winter. The larger bits are absolute beasts; they chewed through wood and mild steel like it was butter. The "Eh, Needs Work": I knocked off a star because of the smaller gauge bits. I tried to drill a pilot hole into a stainless steel bracket, and the small bit just sort of spun around on the surface like a breakdancer. It didn't "bite" at all. It was less of a "drill" and more of a "friction heater." Summary: Durability: High (for the big ones). Value: Great for the price. Performance: 90% excellent. Just be warned: if you need to do fine detail work on hardened stainless steel, the little bits might give you the silent treatment. Still, a solid addition to the toolbox. I’d tell you a joke about a drill, but it’s boring.

Nice drill set in nice container delivered on schedule. I was disappointed it did not contain multiple 1/16 and 1/8 drills as these are the most often broken. I would buy it again.

Quality product at a reasonable price

Took a chance on these cobalt bits because of how many sizes it includes for the reasonable'ish price. The problem is that the quality is very shoddy. The round ends that spin in your chuck are annoying, but over half of the bits I've used so far chip and break instantly upon first use. I'm drilling annealed un-heat treated 1095 steel. My name brand cobalt bits go through like butter, but these... Some of the bits work fine so far, but it's been more miss than hit. I guess it's nice to have all the odd sizes that are included,and they'd probably work on soft materials, but these are made for drilling metal, and they ain't cutting it.

This was a pleasant surprise very inexpensive drill bits to go through steel. It does a great job. I have a deal. It went through was really solid. Had no problems. It’s a winner.

impressions following first, succesful, use. - bits are sharp and straight. - bits are capable of cutting deep into snapped stainless bolts without observable wear. tips: - the metal set case is tightly clipped together when closed and hard to open. instead of force, i've used a small pry tool. - drilling metal: i've started small, slow, then gradually ramped up speed and size - careful throughout. - reminder to drill "backwards" with left-hand bits. in the photo: the two bits that i've used to extract the snapped bolt, also shown.

For so long I went with just whatever came with the drill. These bits are so hard, and with a little bit of oil cuts super well and stays sharp. Left hand is extra handy to drill out broken/welded in screws. Love them. Would bring them to bed if I were allowed.

Bastante satisfecho con la duración, es similar a las brocas Milwaukee titanio pero a un precio menor para ser de cobalto esperaba que duraran un poco más pero aun así muy satisfecho

Works well

I purchased this particular set because I needed a #30 wire gauge drill bit for a project that used 1/8" rivets . The only other option for a SINGLE bit on Amazon was stuck in "neverland" and other sites wanted $30USD for a single bit which was not reasonable. So I found this set for a good price rather than buying them singly. I am significantly impressed with the quality and strength of these bits on 550 stainless and lubricant... Though my unsteady hand meant some failed starts and controlled rpms on my hand drill. (These are probably better on a drill press). Starting the hole was easy enough as was finishing through the mixed materials and the bit did not overheat or wear. I cant say about Cast Iron or Titanium though but your mileage may vary. These would go through pretty much anything else easily as long as you had the right lubrication and Pressure/RPM control. ALL small bits (and these are all smaller than 1/4 of an inch) will break easily so just be mindful of that and go slow and steady without overt amounts of force. The bits are all neatly organized in its index and a small pull tab brings them out as well. Each bit is labelled as is its index for easy use. My only complaint (and I took a star off for this) is that the front label is upside down with no indication or sticker as to which side goes up. Otherwise I had to open my bit box on its side so they didn't all spill out on my table (thanks to reading reviews). I think these are factory rejects because of the label as the bits work just fine and are probably more expensive if the label were to be placed correctly. Otherwise I'm happy with keeping this set for what I will use them for. Though "Wire guide number" bits will not be used too often for me, this set will be very useful in the future.

Nothing