Hymnorq 13-Piece M35 Cobalt Steel Drill Bit Set (2mm-8mm) with Plastic Index Case, Dual Twist Flute, 135° Split Point, and Bronze Finish – Professional-Grade for Hard Metals

At the time I purchased these, I only intended to use them for light duty (drilling into polymer). However, as fate would have it, I had to use them to drill into hardened steel, and much to my surprise, they performed admirably. It was a pleasant surprise (I was expecting "Chinese junk") and I'm very happy with this purchase; especially considering that it's a METRIC set, which is difficult to find (in the USA). I wish the set had a 1mm bit, but oh well. It's just a preference, not anything against the quality of the bits in this set.=============Update 1/16/18=============My rating has changed from 5 stars down to 3. I needed to drill into metal again--actually I wasn't even drilling new holes, but just "chasing" already existing holes to expand them--and neither the 4.5mm or 4.8mm bits would do anything. They just spun around getting hot, without cutting anything. I even tried the 5mm bit, even though that was too big for my purposes, and it also did nothing but spin. Thus, I've used four of the bits (4, 4.5, 4.8, and 5mm), and only one of them did anything. The one that actually worked did its job well; the others are a HUGE disappointment.=============Update 1/25/18=============Kudos to Migiwata customer service (thank you, Bella!). After hearing about my not-so-pleasant experience with these bits, they sent me a second set. Apparently their original supplier had run dry, and they had to use a second, temporary supplier while the original caught up with demand. The first set that I received was from the temporary supplier. The new set is from the original supplier, and the bits seem to be in order in this new set. So how do you tell the difference? By the case (see photos). The set with the blue dot on the case--which is a plastic retainer to keep the case closed--is from the original supplier. Now if you happen to get a set without the blue dot, don't panic. Just because I got a subpar set that slipped through the manufacturer's quality control process doesn't mean that you did, too. Try the bits out first. WORST case is that Migiwata customer service takes care of you like they did me; best case is you don't even have a problem. As for me and my review of this product, I'm a happy camper again and am bumping my rating back up to 5 stars. The bits are great (make sure to use a good cutting lubricant/coolant) and Migiwata customer service is stellar.

You never know how good or bad a drill bit is going to be till you buy it and try it. Hymnorq M35 Cobalt drill bits have been the real deal for me. I've purchased multi-packs of larger daimeter and smaller diameter Hymnorq M35 Cobalt bits that have worked just as well as these 4.2mm bits. Hymnorq M35 cobalt bits are reasonably priced, cut fast, and stay sharp (I do try to take care of them regarding matching RPM to bit diameter and keeping cutting oil on the bits as much as possible). As long as I can continue to find this family of drill bits, I'll continue to replenish my toolboxes with them.

The bits themselves are OK, but definitely not on the higher end (also much lower price than high end bits). The case is poorly molded and low quality. Next time, I'd likely elect to buy a more expensive set.

These drill bits are holding up pretty good they stay sharp even after being used a couple times . I use these drill bits Alot on 5.7 hemi exhaust manifild bolts, the bolts always tend to brake on the cylinder head and I have to drill into the broken exhaust bolts to extract them out and those bolts are pretty much hardened . These bits do there job and bite into The metal your drilling into right away with out walking off. The only down side is having coworkers who like to borrow your drill bits and loose them lol so I gotta buy maybe 2 more sets just to have as back up . There pretty good drill bits they hold up good , haven't had one go dull yet .

As advertised

good set of smaller metric bits

Arrived on time and as described. Works well.

I have bought three of these sets . The drill bits are superior ! They used to come in better cases, but the case is pretty irrelevant for the most part -- it just acts as an index.