13-Piece M35 Cobalt Drill Bit Set, Metric Sizes 1.5mm to 6.5mm, 5% Cobalt HSS for Stainless Steel, Cast Iron & Hard Metal, Fully Ground 135° Split Point with Storage Case

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.

Excellent. Had to drill out a wheel stud. Worked incredibly well.

Sharp, good item

Here in the USA, Metric drill bits are extremely scarce as most of the country insists upon using an outdated Imperial system of drill bit sizes varying from fractions of an inch (21/64" anybody?) to an inverse numbering system (with a #2 being bigger than a #6) Refreshingly, the entirely decimal Metric system comes to the rescue! This Metric drill bit set is sized from 1.0mm to 10.0mm in 0.5mm increments. a most useful selection. The bits themselves are sharp and drill clean holes but the metal case, or drill index is not especially great. For sharpness, in a recent project I drilled 16 x 5mm holes and 10 x 3mm holes through 6mm thick aluminum. The last holes drilled as quickly and cleanly as the first, so they are at least decently sharp and durable. By the way, for those that absolutely can not get their head around millimeters, the smallest 1.0mm drill bit is this set is close to 3/64" and the largest 10mm drill is close to 25/64", or a bit bigger than 3/8"

The 5 mm drill bit was essential repairing a broken 6 mm fastener securing the oil pan to the engine block. After an unsuccessful attempt to remove the bolt using a left hand drill bit and extractor, it was time to drill through the middle of the fasterner, the steel engine block, and tap new threads using an 6 mm x 1 Irwin tap. Adhering to the 60 percent rule of thumb of drilling 60 percent of the actual hole required, a 5.20 or 5.25 mm drill bit was needed, however this drill bit set had 5.0 and then 5.5 mm drill bits in its range. Using the 5.0 drill bit and cutting oil, the drill bit drilled nicely through the bolt and engine steel block. The drill bit did not wobble off center. The Irwin 6 mm x 1 tap from the metric tap and die set purchased from Amazon and using cutting oil cut new threads with ease. I was careful to only cut new threads applying no more than 1/4 or less clockwise turns and then reversing counter clockwise a 1/4 turn. Halfway through the tap I removed the tap completely from the hole, removed the metal shavings using cutting oil, and finished the tap. Installed the new oil pan gasket with the oil pan and torqued the bolts using a Carlyle torque wrench from Napa Parts store to 105-inch pounds. Vehicle back in action. Thanks Migiwata for your metric drill bits. I recommend using this set.

I can't say that they are as god as "Carbaloy" drills or that they are not. I used them on a very tough saw blade and they seemed to loose cutting ability quickly. The Carbaloy drills might not have worked any better but they were not of the size I needed. I did get the hole that I wanted but used drills of differing sizes to expand the hole when the right sized drill stalled before penetration. For the price, though they were fine. This was a metric set and the hole size was not important as long as it gave clearance. You might need SAE size holes and drills for finer work. I'd rate them higher if I had a standard against which to measure them, as they were of good quality manufacture.

This is a nice set of cobalt bits in a metal case, with labelled slots for each bit, each of which is engraved with it's metric size and the "Hss Co" designation. Lots of drill bit for the money, as they go in .5mm increments from 10mm, all the way down to some absurdly tiny ones that I'll never use; but the value is in the number of hefty bits at the upper end of the scale. All bits arrived quite sharp, with no apparent flaws in their construction. As far as their performance, I used them to drill out a wheel stud on my truck, to remove a broken off wheel nut. The smaller bits that I started with worked flawlessly, but one of the larger bits did have part of it's cutting edge chip off, as if it were some kind of coating, but I was using too much positive pressure. The other large ones I used worked great (with my adjusted pressure) and are still sharp enough to be used for future projects. Overall well worth their cost.

This is the best drill bit for drilling out stainless steel screw which is very hard metal. Do not buy the titanium coated for hard steel they go blunt in second.

muito boas

Arrived on time and got what I expected. Very happy

Lo utilizo en acero inoxidable cal. 304 del 18. Siempre he tenido problemas con las brocas. Dos o tres usos y se quedan sin filo. Esta la he utilizado 3 veces y sigue como nueva. Las medidas milimétricas son mucho mas fáciles y tienen mucho mas sentido para mi.