Selecting the right stainless steel drill bits is essential for clean, accurate holes in hard metals, cast iron, and hard plastics. This guide highlights five top-rated options available to UK buyers, focusing on cobalt-enhanced high-speed steel (HSS) for improved heat resistance and longer tool life. Each product section below features practical details to help you compare performance, durability, and value.
| Product | Size Range | Cobalt Content | Main Benefit |
|---|---|---|---|
| HPMAISON True 5% Cobalt Drill Bit Set | 1.5mm–6.5mm | 5% Cobalt (M35) | Heat resistance and long life |
| STROTON 8% Cobalt Twist Drill Bits (1mm–10mm) | 1–10mm | 8% Cobalt (M42) | Heavy-duty performance |
| STROTON Cobalt Drill Bit Set (13Pcs) | 1/16–1/4 inch | 5% Cobalt (M35) | Balanced range for versatile projects |
| amoolo Cobalt Drill Bit Set (13Pcs) | 1.5mm–6.5mm | 5% Cobalt (M35) | Wide size selection |
| PRESCH 6-Piece Cobalt Drill Set | 2–8mm | 5% Cobalt (M35) | Self-centring precision |
HPMAISON True 5% Cobalt Drill Bit Set
The HPMAISON set uses 5% cobalt High Speed Steel (M35) to deliver extended tool life and improved heat resistance compared with standard HSS. The 135° split-point design helps prevent walking and aids chip clearance, while the straight shank ensures compatibility with common drill chucks. Suitable for stainless steel, cast iron, and other hard metals, this set supports efficient drilling across a range of sizes from 1.5mm to 6.5mm. Precision grinding and a gold oxide finish contribute to smoother chip removal and longer service life under demanding conditions.
STROTON 8% Cobalt Twist Drill Bits (1mm–10mm)
This STROTON set uses premium M42 8% cobalt steel, delivering superior heat resistance, wear resistance, and long tool life for challenging materials. The 68–70 HRC hardness supports fast drilling through stainless steel, hard metals, and similar substrates. A three-step design enhances cutting through tough alloys, while the set’s high efficiency allows faster operation and lower cost per hole over time, despite a higher upfront price. The 19-piece assortment covers a broad range to suit complex projects.
STROTON Cobalt Drill Bit Set (13Pcs)
This 13-piece STROTON cobalt set features M35 high-speed steel with a 68 HRC rating, yielding enhanced heat, wear, and chip resistance. The split-point and fully ground production help prevent wandering and promote clean hole finishes, especially when drilling stainless steel, cast iron, or hardwood. The set’s design emphasizes efficiency, enabling faster hole creation while maintaining tool longevity, making it suited to frequent, professional use.
amoolo Cobalt Drill Bit Set (13Pcs)
amoolo offers a 13-piece selection ranging from 1.5mm to 6.5mm, all in a durable plastic case for storage. The bits use 5% cobalt (M35) for added hardness and heat resistance, with Rockwell hardness up to 67. They are well-suited for hard metals, stainless steel, and cast iron, with recommended use on wood and softer metals as well. The set emphasizes versatile applications across metalworking and fabrication tasks, while cautioning users to manage speed and pressure to maximize tool life.
PRESCH Metal Drill Set HSS Cobalt 6 pcs
PRESCH presents a compact 6-piece cobalt set designed for stainless steel and tough metals. Constructed with 5% cobalt, these bits deliver enhanced heat and wear resistance and are described as self-centring for precise starts. The Austrian design heritage suggests durability under repeated use, with a temperature tolerance up to around 600°C. The kit is ideal for users who need dependable small-diameter drilling in metalworking, electronics enclosures, and similar tasks.
Buying Guide: Key Considerations When Choosing Stainless Steel Drill Bits
- Material and cobalt content: Higher cobalt (M35 or M42) offers superior heat resistance and longer life, especially for stainless steel and cast iron. Balance cost with expected wear.
- Tip geometry: A 135° split-point reduces walking and improves centering, while a fully ground edge provides smoother cutting and chip removal.
- Shank design: Straight shanks ensure compatibility with standard drill chucks. Some sets include indexed storage or cases for organization.
- Size range: For routine work, choose a set with a broad range of sizes (e.g., 1.5–6.5 mm or 2–8 mm) to cover common applications without swapping bits.
- Application guidance: Most cobalt HSS bits work well on stainless steel, cast iron, and hardened metals. Avoid use on glass or ceramic materials unless specifically noted.
- Speed and feed: Higher speeds (as advised by manufacturers) improve performance with cobalt bits. Use steady pressure and avoid overheating the workpiece.
- Durability versus price: Cobalt sets may cost more upfront but typically offer lower cost per hole due to longer tool life, especially in demanding tasks.
- Storage and organization: A case or indexed box helps prevent loss of small bits and keeps sizes clearly identified for quick access.