Grewin Bull – Type H Rotary Burr
Compound Round-Head Cone Tool for Angle and Surface Transition Processing
Overview
The Grewin Bull Type H rotary burr features a round-head conical design, combining the angle machining capability of Type C with the smooth surface transition of Type D.
It is the ideal tool for filleted chamfers, sloped surfaces with rounded transitions, and complex geometries requiring both angles and curves.
Widely used in mold making, precision machining, automotive manufacturing, and aerospace industries.
Features
- Tungsten carbide material: extremely hard, wear- and heat-resistant, long service life.
- High-speed cutting: capable of machining hardened steels.
- Double-cut cross pattern: smooth cutting, reduced chatter, improved surface quality.
- Versatile processing: combines angle cutting and fillet forming in one operation, boosting efficiency.
Suitable Materials
- Metals with hardness ≤ HRC55
(carbon steel, alloy steel, stainless steel, etc.)
Applications
- Mold industry
- Precision machining
- Aerospace manufacturing
- Automotive manufacturing
Technical Specifications
- In compliance with ISO 7755-1984(E)
- Available in 12 models, 78 specifications
- Supports custom-made rotary burrs, trial production, and OEM services
Usage & Maintenance
- Safety: always wear goggles and cut-resistant gloves to protect against flying chips.
- Proper force: avoid excessive pressure to prevent overheating and premature wear.
- Cleaning: regularly remove debris to maintain sharpness and efficiency.
- Speed control: use recommended high speeds; adjust according to material hardness.
Case Study — Large Mold Surface Repair
For large injection molds or die-casting molds requiring wide surface restoration, the Type H rotary burr is mounted on a high-speed pneumatic grinder.
Its arc-shaped cross-section fits large curved surfaces, enabling efficient material removal and smooth transition shaping.
Results:
- Fast and precise surface repair
- Improved transition quality
- Enhanced mold surface finish
- Excellent preparation for polishing
