Cobalt Drill Bits
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About Cobalt Drill Bits
Cobalt drill bits are premium drilling tools engineered for working with hardened materials that would quickly blunt standard HSS bits. Containing 5-8% cobalt alloy blended throughout the entire steel construction, these specialist bits deliver exceptional heat resistance and cutting edge retention when drilling stainless steel, cast iron, hardened steel, and titanium. MyToolShed.co.uk stocks an extensive range from leading manufacturers including DeWalt, Bosch Professional, Dormer, Irwin, Draper Expert, Faithfull, and Sealey.
Our selection includes individual jobber length cobalt drill bits in various diameters alongside comprehensive multi-piece sets ranging from compact 5-piece kits to professional 29-piece collections. Most feature HSS-E or HSS-Co construction with M35 specification (5% cobalt content), incorporating split point tips and 135° point angles optimised for hard material drilling. Whether you need a single replacement bit or a complete workshop set, MyToolShed offers quality options for every requirement and budget.
Applications
Cobalt drill bits are essential for tradespeople and industries working with tough materials:
- Metal Fabricators and Welders: Drilling structural steel, angle iron, and heavy plate steel
- Maintenance Engineers: Repairing industrial machinery, motors, and equipment with hardened components
- Automotive Technicians: Working with chassis rails, suspension parts, and hardened automotive steel
- Agricultural Engineers: Drilling farm machinery, plough blades, and heavy-duty equipment
- Plumbers and Heating Engineers: Penetrating cast iron pipes, radiators, and stainless steel fittings
- Aerospace and Precision Engineering: Machining specialised alloys and titanium components
- Construction Steelwork Contractors: Installing fixings in structural steel frameworks
Choosing The Right Cobalt Drill Bits
Individual Bits vs. Sets: Multi-piece sets from DeWalt, Draper Expert, or Faithfull offer better value for regular metalwork, whilst individual bits suit occasional specialist drilling needs.
Cobalt Content: M35 specification bits (5% cobalt) handle most applications including stainless steel and cast iron. M42 specification (8% cobalt) provides maximum heat resistance for the most demanding industrial work.
Size Range: Consider your typical drilling requirements. Starter sets typically range from 1mm to 10mm or 13mm, whilst professional collections like the DeWalt 29-piece offer comprehensive coverage. Metric sizing is standard throughout the UK trade.
Brand Quality: Premium brands like Bosch Professional, Dormer, and DeWalt deliver superior manufacturing tolerances and extended service life. Mid-range options from Draper Expert, Faithfull, and Sealey provide excellent value for professional use.
Point Design: Split point tips prevent wandering on hard surfaces and are highly recommended. Most quality cobalt bits feature 135° point angles specifically optimised for hard material drilling.
Frequently Asked Questions
What's the difference between cobalt drill bits and standard HSS bits?
Cobalt drill bits contain 5-8% cobalt alloy throughout their entire structure, making them significantly harder and more heat-resistant than standard HSS bits. This enables them to drill hardened steel, stainless steel, and cast iron that would quickly destroy conventional bits. Though more expensive initially, their extended lifespan in hard materials makes them more economical for professional metalwork.
Do I need cutting fluid when using cobalt drill bits?
When drilling hardened steel, stainless steel, or similar tough materials, cutting fluid significantly extends bit life and improves performance by reducing heat and friction. For occasional drilling of softer metals you can work dry, though lubrication always benefits results. Professional metalworkers typically use appropriate cutting fluid to maximise their investment in quality cobalt bits.
Will cobalt drill bits work in a standard cordless drill?
Yes, cobalt bits fit standard drill chucks and work with both corded and cordless drills. However, drilling hard materials requires adequate power and torque. Premium 18V cordless drills from DeWalt, Milwaukee, or Makita typically provide sufficient power for most hard drilling applications, though corded drills or magnetic drill stands may be preferable for heavy-duty metalwork.