Dormer A777 HSCo Heavy-Duty Cobalt Drill Bit, 4mm
Durable cobalt steel Dormer A777 drill bit (4mm) with 135° split point for aerospace & tough materials.
The Dormer A777 HSCo Heavy-Duty Cobalt Jobber Drill Bit is engineered for demanding drilling applications where high heat generation is expected. This drill bit features a 135° split point design that ensures precise starting and reduced walking, making it ideal for tougher, higher tensile materials commonly found in the aerospace industry.
Constructed from HSCo cobalt steel, these bits offer exceptional durability and heat resistance. They feature a standard helix, right-hand spiral, and thick web geometry for improved strength and chip evacuation. The bronze surface treatment provides additional corrosion resistance and extended tool life.
Point Angle Specifications
- 0.30mm - 0.95mm: 118° conical point
- 1.00mm - 1.40mm: 135° 4-facet point
- 1.50mm and above: 135° split point (meeting NAS 907 Aerospace Specification type P3 Point)
These drill bits comply with DIN 338 RN, BS328, and ISO 235 standards, assuring professional-grade performance in industrial applications. The 4.0mm tip diameter and 43mm working length (75mm overall length) make this an excellent choice for precise drilling jobs where space and accuracy are critical.
- High-tensile materials
- Aerospace industry applications
- Precision drilling in tough metals
- Industrial metalworking
- Material: HSCo Cobalt Steel
- Flute Geometry: Standard Helix, Right Hand Spiral, Thick Web
- Point Angle: 135° Split Point (for sizes 1.50mm and above)
- Surface Treatment: Bronze
- Tip Diameter: 4.0mm
- Working Length: 43mm
- Overall Length: 75mm
- Weight: 5g
- Standards: DIN 338 RN / BS328 / ISO 235
Always follow local regulations and product guidance.
Free standard delivery on US mainland orders. Express delivery options and international shipping available at checkout.
We offer a 30-day money-back guarantee on most products. For defective items, contact us within 14 days for a replacement or refund.
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