Grewin Bull – Type D Rotary Burr
Ball Head Design · Specialized for Concave Surfaces and Inner Radii
Product Overview
The Grewin Bull Type D rotary burr features a ball head design, making it ideal for smooth machining of concave surfaces (inner radii) and irregular free-form surfaces.
When precision finishing of curved surfaces, inner corners, or complex 3D profiles is required, the Type D ball-head burr is the irreplaceable choice.
Features
- Material: Tungsten carbide – the most widely used and premium material. Extremely hard, wear-resistant, heat-resistant, and long service life. Capable of high-speed cutting of hardened materials, including quenched steel.
- Application Range: Suitable for machining metals with hardness up to HRC55 (carbon steel, alloy steel, stainless steel, etc.).
- Design: Hemispherical head, cylindrical body with cross-cut teeth.
- Performance Advantages:
- Exceptional ability for surface finishing
- Smooth and natural radius transitions
- High material removal efficiency
Application Fields
- Mold industry
- Precision machining
- Aerospace manufacturing
- Automotive industry
Technical Specifications
- Standard: ISO 7755-1984(E)
- Available in 12 types / 78 specifications
- Services: contract processing, sample trial production, and non-standard customization
Usage & Maintenance
- Safety: Wear safety goggles and cut-resistant gloves to prevent debris injuries.
- Cleaning: Regularly remove chips to maintain optimal performance.
- Moderate Force: Avoid excessive pressure to prevent overheating or premature wear (reduce speed for extended tools).
- Speed Control: Designed for high-speed operation; adjust RPM depending on the workpiece material.
Case Study – Chamfering and Deburring of Holes
Scenario: After drilling steel plates, sharp burrs appear at the hole edges, affecting assembly and posing safety hazards.
Problem: Dozens or even hundreds of holes need consistent chamfering and deburring. Hand files are inefficient and inconsistent.
Solution:
- Operator selects a Type D cross-cut rotary burr and mounts it on a pneumatic die grinder.
- The ball head is gently inserted into the hole edge and rotated.
- The hemispherical design naturally cuts a uniform and smooth chamfer, while the cross-cut teeth ensure high-speed burr removal.
Result:
- Each hole is chamfered and deburred in just 1–2 seconds
- Chamfers are neat and consistent across all holes
- Dramatically improved efficiency and surface quality
