Bosch CO2135 2-3 Cobalt Drill Bit Review

Used to drill 5 old computer hard drives prior to recycling. This drill went through different drives with an old hand drill. The cost was extremely low and it saved me from having to use a sledgehammer to smash the discs into an unreadable state. I was amazed that it arrived the next day with first class delivery. What do you have to lose?

These are the strongest parts I have found. They last far longer than any other bit I've used on steel. I tried many and continued to wear down the bits as I built the steel magazine until I did some research and found that cobalt should last a long time. Cobalt pieces weren't available locally, so I bought them here and from Menard. They are taller but slightly larger.

Needed to drill some steel rivets and the other bits in my arsenal didn't fit. Ordered this and the 1/4" size and they worked like clockwork. I didn't use lube because I was cheap/lazy and worked really hard on these rivets - no breakage, little wobble, vengeance or anything of the sort. of these bits .They seem excellent and I will definitely buy from Bosch again if I need other sizes.

This drill bit is essential for my jewelry use. This is one of the few drill bits I can use to drill through stainless steel. Work slowly, use Cut Lube and water spray to prevent the drill from overheating on thicker parts. Once the tip turns red, the stroke isn't as effective and I need to change it. I usually buy 10 and use titanium bits when not working with stainless steel.

worked great. On my 20 year old minivan, a tailgate support post failed, startling my wife and scratching her hand. The support bolt broke about halfway down the hole. I tried one of those screw extraction sets but it just didn't grab, the screw was too hard and the angle didn't help. Saw this piece and thought "why not?" It got here in no time with Prime delivery and the price was great. He quickly removed most of the broken bolt and I was able to use an extractor to finish it off. This bit…

TERRIBLE and I love to write a lot of five star reviews. This is one of two cobalt drill bits from Bosch that broke trying to drill through hardened steel in about 1 minute. And I got on the phone with a Bosch rep about how this type of drill is best for hardened steel (something that was difficult to drill). It's actually spring steel like that found on many pistol holsters, extremely strong BUT I've never had a bit break completely in two, ESPECIALLY two bits and under a minute! And I have…

I've only tested it a few times on thick angle steel and once on stainless steel, but no sign of dulling. He pierced it like butter after my cheap port cargo drill just sat on the surface making a hot groove instead of a hole. I've used cutting fluid (WD-40 or water if you don't have cutting fluid on hand) and I always recommend using cutting fluid and also cooling off any smoke or smell of hot metal/fluids. Getting the drill too hot is the best way to ruin it, let alone use it as a tool. I…