Cobalt HSS drill bit set for drilling stainless steel and hardened metal.
- Cobalt alloyed HSS for heat and wear resistance
- 135° self-centring split point tip
- Manufactured to DIN 338 standard
- 25 pieces, 1mm to 13mm in 0.5mm increments
- Cylindrical shank fits standard drill chucks
- Supplied in a metal index case
Cobalt HSS Drill Bit Set 1-13mm - 25 Piece with Metal Case
Cobalt HSS drill bit set for drilling stainless steel and hardened metal.
- Cobalt alloyed HSS for heat and wear resistance
- 135° self-centring split point tip
- Manufactured to DIN 338 standard
- 25 pieces, 1mm to 13mm in 0.5mm increments
- Cylindrical shank fits standard drill chucks
- Supplied in a metal index case
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Log in to access trade discountsCobalt HSS Drill Bit Set 1-13mm - 25 Piece
Cobalt HSS drill bit set built for drilling stainless steel, hardened steel and cast iron without losing its edge. The 25-piece range covers 1mm to 13mm in 0.5mm increments, manufactured to DIN 338 with a 135° self-centring split point for accurate, wander-free starts. Supplied in a metal index case that keeps every size organised and protected on site.
How cobalt content keeps the edge under sustained heat
Standard HSS bits lose their edge quickly when drilling stainless steel or hardened metal, since the heat generated during sustained drilling softens the cutting edge and dulls it far faster than in softer materials. That means more frequent bit changes, slower progress and inconsistent hole quality across a job. Cobalt alloyed into the HSS raises its heat resistance significantly, letting the bit hold its edge through the higher temperatures generated when drilling tougher metals, so it keeps cutting cleanly for longer.
Key Features
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Cobalt alloyed HSS construction: Holds its cutting edge under the heat generated drilling stainless steel and hardened metals, where standard HSS dulls quickly.
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135° self-centring split point: Starts the hole exactly where needed, reducing wander and improving accuracy across every size in the set.
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Manufactured to DIN 338: Meets the recognised standard for twist drill dimensions and tolerances.
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25-piece range, 1mm to 13mm: Covers a comprehensive spread of diameters in 0.5mm increments for most metal drilling tasks.
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Cylindrical shank: Fits standard three-jaw drill chucks on corded and cordless drills.
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Metal index case: Keeps every size organised, protected and easy to identify on site.
Who is this for
Trades and roles:
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Fabricators and metalworkers
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Maintenance engineers
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General site operatives
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Installers and fitters
Industries:
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Manufacturing and fabrication
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Construction and civil engineering
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Facilities maintenance
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General engineering
Specifications
| Specification | Detail |
| Product Name | Cobalt HSS Drill Bit Set 1-13mm - 25 Piece with Metal Case |
| SKU | COBKM25 |
| Material | Cobalt alloyed high speed steel (HSS) |
| Standard | DIN 338 |
| Point Type | 135° self-centring split point |
| Shank Type | Cylindrical |
| Set Size | 25 pieces |
| Diameter Range | 1mm to 13mm in 0.5mm increments |
| Case Type | Metal index case |
| Suitable Materials | Stainless steel, hardened steel, cast iron, alloy steel |
Compatibility
| Application or condition | Status |
| Stainless steel and hardened steel drilling | ✓ Compatible |
| Cast iron and alloy steel drilling | ✓ Compatible |
| Standard three-jaw drill chucks | ✓ Compatible |
| Wood and plastic drilling | ✗ Not recommended |
| Masonry, brick or concrete drilling | ✗ Not recommended |
| Use in an SDS or hammer drill without a suitable chuck adaptor | ✗ Not recommended |
Who is this for
This set is used by fabricators and metalworkers drilling stainless steel, hardened steel and cast iron, where a standard HSS bit dulls too quickly to be practical. Maintenance engineers and installers use it as a comprehensive general metal drilling set, since the 25-piece range covers most diameters needed without buying individual bits. It suits any role needing reliable, repeatable results across a wide range of hole sizes.
Typical applications
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Drilling stainless steel components in fabrication and manufacturing work.
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Drilling hardened steel, cast iron and alloy steel in general engineering tasks.
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Creating pilot holes and clearance holes across a range of diameters on metal fittings.
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General maintenance and installation work involving metal drilling.
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Stocking a workshop or site van with a comprehensive metal drilling range.
How to use
Step 1: Select the correct diameter bit from the case for the hole required.
Step 2: Fit the bit into a standard three-jaw drill chuck and tighten securely.
Step 3: Position the self-centring split point on the marked drilling location before starting the drill.
Step 4: Drill at a speed suited to the material and bit diameter, using cutting fluid on stainless steel and hardened metals where appropriate.
Step 5: Return the bit to its correct slot in the metal case after use to keep the set organised.
Common mistakes
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Running the drill too fast on stainless steel or hardened metal, generating excess heat that dulls the bit prematurely.
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Not using cutting fluid on tougher materials, reducing bit life and drilling quality.
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Forcing the bit rather than letting it cut at its own pace, increasing the risk of snapping smaller diameters.
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Mixing bits up outside their case, making it harder to select the correct size quickly.
Safety
Wear eye protection when drilling, since metal swarf and fragments are thrown off during use. Secure the workpiece firmly before drilling to prevent it spinning or shifting. Allow bits to cool before handling after extended use, since sustained drilling generates significant heat.
Maintenance
Keep bits clean and free from swarf build-up after use. Store in the metal case to protect the cutting edges from damage. Replace any bit once it stops cutting cleanly or the edge shows visible wear, rather than continuing to force a dulled bit.
Frequently Asked Questions
Q: What does cobalt content actually add to an HSS drill bit?
A: Cobalt alloyed into the high speed steel increases its heat resistance, letting the bit hold its cutting edge at the higher temperatures generated when drilling stainless steel, hardened steel and cast iron. Standard HSS bits dull much faster under that heat, needing more frequent replacement when used on tougher materials.
Q: What does the DIN 338 standard cover?
A: DIN 338 is the recognised European standard for twist drill bit dimensions and tolerances, covering diameter, length and shank specifications. Manufacturing to this standard confirms the bits meet consistent sizing across the full 25-piece range.
Q: What is this set NOT suitable for?
A: This set is designed for drilling metal, not suitable for masonry, brick or concrete, which require a dedicated masonry or SDS bit. It also isn't optimised for wood or plastic, where a standard wood bit gives cleaner results.
Q: Why choose a cobalt bit over a standard HSS or titanium coated bit?
A: A titanium coating wears off with use, and once it's gone, the underlying bit performs like standard HSS. Cobalt is alloyed through the entire bit, so the heat resistance doesn't wear away over time, giving more consistent performance across the bit's working life on tough materials.
Q: What does the 135° split point tip do?
A: It gives the bit a self-centring action, so it starts cutting exactly where positioned rather than wandering across the surface before biting in. This improves accuracy and reduces the need for a separate centre punch mark on most materials.
Q: How many sizes are included, and what's the range?
A: The set includes 25 bits covering 1mm to 13mm in 0.5mm increments, giving a comprehensive range for most metal drilling tasks without needing to buy individual sizes separately.
