Best Cobalt Drill Bits for Metal – Tested & Proven
SGS-tested cobalt drill bits that drill stainless steel, hardened steel, and tough alloys with ease. Trusted by locksmiths, mechanics, and engineers worldwide.
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Best cobalt drill bits : Customer testimonials
Hello there….I just thought I’d drop you a line commending your products. The 6,5,4 and 3 mm drill bits work a treat on my stainless steel cycle rack. Initially I ran the drills too fast and I didn’t use enough pressure which resulted in poor performance, particularly on the larger drill sizes. I quickly learned that slowing the drill down and increasing drill pressure whilst ensuring enough cutting grease had been applied enhanced the drilling performance immensely. It used to frighten me when drilling stainless steel. NOT ANY MORE! Well done your Company! Trevor Ball
Why Choose TTP HARD Cobalt Drill Bits?
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✅ SGS hardness tested (Rockwell 66)
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✅ 5% cobalt through the body, not just coated
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✅ Works on hardened steel, stainless, spring steel
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✅ Independent reviews on YouTube (Wayne Winton, DIYMark, Catus Maximus)
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✅ Backed by 100% satisfaction guarantee

Cobalt Drill Bits – Sets & Individual Sizes Available
All our cobalt drill bits are sold individually, but sets offer the best value and complete coverage of common sizes.
SGS Hardness Tested • 100% Guarantee • Fast UK Shipping
| Category | Sizes Included | Best For | Shop |
|---|---|---|---|
| 19-Piece Metric Set | 1mm – 10mm (0.5mm increments) | Everyday mechanics & installers | BUY NOW |
| 25-Piece Metric Set | 1mm – 13mm (0.5mm increments) | Full workshop coverage | BUY NOW |
| All Metric Sizes | Singles & 10-packs (1mm – 13mm) | Replace worn bits or buy in bulk | BUY NOW |
| All Imperial Sizes | Singles, 21 & 29 piece sets (1/16″ – 1/2″) | Imperial projects & US/locksmith work | BUY NOW |
Cobalt drill bits reviewed
We sent our drill bits to renowned locksmith Wayne Winton from Tri-County Locksmiths in Colorado to see what he thought of them. Here are just 2 of the videos he posted on Youtube.
Check out the Wayne Winton youtube site for more videos where he tested TTP HARD drills on all kinds of metal.
Reviews from some of our clients who rank TTP HARD drills as the best cobalt drill bits for drilling harder metals including stainless steel.
Drilling stainless steel
Hello there….I just thought I’d drop you a line commending your products. The 6,5,4 and 3 mm drill bits work a treat on my stainless steel cycle rack. Initially I ran the drills too fast and I didn’t use enough pressure which resulted in poor performance, particularly on the larger drill sizes. I quickly learned that slowing the drill down and increasing drill pressure whilst ensuring enough cutting grease had been applied enhanced the drilling performance immensely. It used to frighten me when drilling stainless steel. NOT ANY MORE! Well done your Company!
Drilling hardened steel
Best drill bits I’ve ever used by far, I purchased several different cobalt bits trying to drill into a broken cylinder head bolt to extract it and not one would do more then scratch the hardened head bolt. After hours of trying to drill into the broken bolt I decided to go online and find a different type of bit, after watching many videos about these bits I decided to purchase a full set with their ‘in house lubricant’ as well. Within 10 mins I had the broken bolt drilled and extracted,
Drilling tensile bolts
I was very happy with my purchase of the tough drill bits , they allowed me to drill out some broken off tensile bolts from a 25 year old motorbike cylinder head , failure in this would have meant finding a new head or abandoning the project
Cobalt drill bits save the day
I broke two stainless bolts in the head of my ex-US Army jeep engine which defied left hand bits, quality HSS right hand bits, gas and brute force. They were just an inch long and eventually we got a small pilot hole and a pile of blunt drills. I read that cobalt drills were worth trying, found the TTP site, saw the videos and ordered two of two sizes (in case they got blunt?). A decent-ish corded drill and a single TTP just sliced through both bolts using plenty of oil and low speed as advised in the vid and info leaflet.
After a wipe with a rag the drills went in the tool box – though I couldn’t tell which was the used one and which was unused.
It sounds corny but I should have got the TTP drills earlier and saved a lot of time and hassle.
Drilling tough steel
I was struggling with some tough steel washers I needed to drill three small holes into around the circumference.
I had already wasted a mix of various ten HSS, Tungsten and Titanium coated drills without even successfully drilling one hole and was running out of ideas. After trawling the internet I came across the TTP drills and was so impressed with the video I ordered a selection of sizes to try them out. What a difference! A firm pressure and some jiggling with the drill speed soon resulted in the drilling of all the holes with one drill and with the same curl of swarf seen on the video. The other drills produced dust, if I was lucky.
I also used the TTP drill cutting paste which now occupies pride of place on my workbench.
TTP may sell tough products but I found them anything but tough to deal with, communications were excellent and the drills arrived on time and well packaged. I would deal with them again without hesitation and can highly recommend their products and service. Thanks TTP.
Drilling hard plate on safes
They are amazing. Didn’t believe the hype, but it appears to be true. I am a locksmith and drill hard plate on safes. They really tore into it.
Drill bits for a locksmith
This is Wayne Winton with Tri County Locksmith Service. I have used the TTP-HARD-drills and personally feel they are some of the highest quality drill bits I have ever used. They work well on a variety of steels from hardened spring steel to brass and aluminium, all with fast cutting speed and easy drill point starting. They are far superior to the average drill bits that can be purchased at the local hardware store. They have put much time and research into their product and it shows in pure performance. These drill bits are in my service truck and will be for a long time.
Drilling exhaust manifold studs
They are fabulous. I still haven’t had the time to use them for their actual intended purpose – drilling out exhaust manifold studs, but I did try them out on a couple of bolts to see how they did and was very impressed! Told a bunch of my friends about them. Hoping to get a joint order together. I want more sizes or one of the sets!
Drilling hard steel easily
Just to let everyone know these drill bits are BRILLIANT, it is the first time I have ever worked with metal and was using Bosch titanium bits, managed 3 holes with 3mm drill bits. Then I ordered TTP bits and they were like a hot knife through butter. I was drilling 1cm hard steel and the job was so easy. Highly recommended, don’t buy expensive imitations.
FAQ’s
Q: Who makes the best cobalt drill bits?
A: Independent reviews from locksmiths and mechanics rate TTP HARD cobalt bits among the best for hardened steel, stainless steel, and tough alloys.
Q: Are cobalt drill bits better than HSS?
A: Yes. Cobalt bits resist heat and cut hardened steels more effectively than standard HSS, making them a better choice for tough jobs.
Q: Can cobalt drill bits drill hardened steel?
A: Yes. TTP HARD cobalt bits have been tested on hardened bolts, tensile steel, and safe hard plates with excellent results.
Q: Are cobalt drill bits good for stainless steel?
A: Absolutely. Stainless can “work harden” if drilled incorrectly, but cobalt bits with cutting paste handle it reliably.
Q: What is the best cobalt drill bit set?
A: For metric jobs, the 25-piece set (1–13mm) is most versatile. For imperial, the 29-piece set (1/16″–1/2″) covers all common workshop needs.


