Premium Cobalt Drill Bits – For Stainless & Hard Metals
Drill stainless steel, hardened bolts, cast iron and more with ease. Our SGS-tested cobalt drill bits are trusted by UK mechanics, engineers & locksmiths. Buy individual sizes or full sets. Fast UK shipping, guaranteed results.
We Also supply specialist Repair Products 
See Our Drill Bits in Action
Watch professional reviews showing our cobalt drill bits cutting through stainless, bolts and tough metals. See real results before you buy.
Why Choose TTP HARD Cobalt Drill Bits?
- ✔️ 5% cobalt through the bit – not just coated
- ✔️ SGS hardness tested (Rockwell 66)
- ✔️ Cuts stainless steel, spring steel, cast iron & more
- ✔️ Works with hand drills & drill presses
- ✔️ Fast UK delivery – 100% satisfaction guarantee
Shop Cobalt Drill Bit Sets & Sizes
Choose from full sets or individual sizes in both metric and imperial:
- 🔩 19-Piece Metric Set – Ideal for everyday use
- 🧰 25-Piece Metric Set – Full coverage (1mm to 13mm)
- 📏 All Metric Sizes – Sold individually or in packs
- 📏 All Imperial Sizes – 1/16″ to 1/2″, including 21 & 29-piece sets
What Are Cobalt Drill Bits?
Cobalt drill bits are designed for cutting through tough metals and alloys. Most contain either 5% cobalt (M35) or 8% cobalt (M42). While 8% cobalt bits handle heat extremely well, they tend to be more brittle. For this reason, they’re best used in controlled environments like pedestal drills, where precise angles and steady speeds can be maintained.
However, for general-purpose and hand drilling, 5% cobalt (M35) bits are typically the better choice. They offer more flexibility and are less prone to snapping under uneven pressure. Thanks to their abrasion resistance and red hardness, these bits still deliver excellent performance on hardened metals and alloys.
Why Choose TTP HARD Cobalt Drill Bits?
1) Independently Tested for Quality
To ensure top performance, our drill bits were put through independent testing by two of the world’s leading materials laboratories. These tests confirmed their hardness and strength. Additionally, our metal cutting paste has undergone pressure-resistance testing, with full report and video footage available to support the results.
2) Made to Withstand Heat and Wear
The addition of cobalt in the alloy offers several performance benefits:
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Retains cutting strength even at high temperatures (known as red hardness)
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Resists abrasion, which helps reduce heat build-up during drilling
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Can be resharpened, which extends the working life of each bit
As a result, these drill bits are ideal for both professionals and serious DIY users.
3) Preferred by Professionals Across the UK
Because of their reliability and clean cutting ability, our drill bits are a top choice among installers, locksmiths, and mechanical fitters who regularly work with hardened steel. DIY customers have also shared positive reviews after using them on difficult metal jobs.
Whether you need a specific metric or imperial size or a complete set for drilling stainless steel and other hard metals, we offer dependable options that deliver.