Migiwata Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bits with Straight Shank Set of 13pcs to Cut Through Hard Metals Such as Stainless and Cast Iron

I was impressed first with the fast shipping and also impressed with the drill bits They come in a very nice case and each drill bit has its own numbered slot. Now I have not had a chance to use them yet but they look to be of great quality for the price. I wanted drill bits for drilling steel and these look like they can handle the job.

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.

These cobalt drill bits are very good, very easy to drill through hard metal, unlike my set of titanium drill bits. I had problem with a 3mm drill bit, the surface that I tried to drill wasn’t flat, took a bad angle and snapped the bit. Contacted the seller, send me a remplacement right away. That’s excellent service.

This is a good quality product for your money. Bits perform well for a cheaper product. Bores through iron and stainless steel well, even without cutting oil. But would recommend cutting oil for longer life of the bits.

Mala calidad de las brocas, se rompen facilmente.