Cobalt Drill Bit Set, 5/16" (10pcs) 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 work with metal daily, so I go through a lot of drillbits. cobalt is great for working with metal but it can be brittle if you don’t know what you’re doing. I read some complaints about people snapping their bits and I have yet to do so, and have been using them for months. For the most part, they stay sharp and cut well as long as you take care of them and use them at the proper speed and pressure. The size of the set provides the sized bits needed so that I can properly drill and tap a hole. The one major problem I have with this set is the rounded shaft. All bits are completely round and if your bit bites in the medal, the drill chuck will spin and strip on the shaft. This will happen often especially with the larger bits. That’s annoying in itself but when makes it really bad is the fact that the drillbit sizes are etched exactly in that area, so you essentially strip off the drillbit size label very easily, and the only way to make sure you have the correct size, is you must stay organized and keep it in its case and its proper spot. For this reason, I highly recommended purchasing the option with the metal case provided. Overall, it’s a great set and I’d likely buy it again based on its price point and quality.

Quality product at a reasonable price

I had a use case where a machine screw had broken off in a location that wasn't easy to access. I decided versus pulling the piece of equipment apart to improve access, I'd spend the money on a set of these with the hopes it would catch as I was drilling out the broken off screw. The screw broke during installation, so I wasn't worried about rust or anything like that, and the roll of the dice paid off. As I slowly increased the size of the bits, one finally caught and backed it out. I replaced the machine screw with a new one and job done. This set saved me about an hour of disassembly and for me, that made the set worth the price. I don't know long-term how they'll hold up, but for me, these will be used infrequently and as I mentioned, they've already paid for themselves, so future use is just money in the bank. The case is nice and the quality seems good, so no regrets here.

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.

The MACXCOIP 13‑Piece M35 High Speed Steel Cobalt Drill Bit Set looks solid in the listing, but in practice these bits are very basic and don’t perform well on tougher materials like stainless steel. Wobble There’s a noticeable wobble when drilling, especially with the smaller bits. They don’t track straight, which makes precision work difficult. Drillability Despite being advertised for hardened metal and stainless steel, I couldn’t get through a 1/4” stainless steel plate even using a high‑power corded drill. They dull quickly and lose bite almost immediately on harder metals. Breakability These bits overheat fast, and once they get hot, they deform and snap into pieces if you apply even moderate pressure. Breakage is a real issue. Ease of Use They’re fine for soft materials like wood, plastic, or aluminum, but anything beyond that becomes frustrating. Frequent stopping to cool the bit or swap to a new one slows everything down. Durability Durability is the biggest weakness. The M35 label suggests higher heat resistance, but in practice they wear out and break far too easily. Look The set looks decent in the index storage case, and the bits have a clean finish out of the box, but the appearance doesn’t match the performance. Customer Service After posting this review as a 2/5 review the seller/manufacturer reached out to me without request offering me a full refund, no questions asked, no request to take down or modify my reviews. That said, I felt that was a class move and shows great customer service which deserves a star on its own so I’ve increased my score to 3/5. Overall, with the star added for great customer service this is a 3/5: a basic cobalt drill bit set that’s okay for light materials but fails quickly on stainless steel, overheats, and breaks under pressure. You get what you pay for here.

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.

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

No era lo que esperaba muy caras y son de medida muy pequeñas, no llegan ni alos 10mm. Yo buscaba de 8mm. sta 14mm. Pero la descripción está muy confusa

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.