Grewin Bull – Type B Rotary Burr
Cylindrical with End Cutting Edge · Versatile All-in-One Metalworking Tool
Overview
The Grewin Bull Type B rotary burr adopts a cylindrical design with an end cutting edge, making it one of the most versatile and widely used models in the rotary burr family.
It is ideal for surface milling, root cleaning, step hole machining, and bottom slot milling. Compared with Type A, the Type B offers stronger functionality and a broader range of applications.
In most cases, when unsure whether to choose Type A or Type B, Type B is the safe choice, as it covers all the functions of Type A while offering greater flexibility.
Type A is specialized (focused on sidewalls), while Type B is universal. In modern machining applications, the value of Type B is even more prominent.
Features
- Carbide Material: Premium, mainstream choice; extremely hard, wear-resistant, and heat-resistant; long service life.
- Wide Applicability: Capable of high-speed cutting of hardened steels and other hard materials.
- Workpiece Hardness: Suitable for metals with hardness below HRC55 (carbon steel, alloy steel, stainless steel, etc.).
- Double-Cut with End Teeth: Enables both side and end cutting, providing unmatched root-cleaning capability and all-round machining flexibility.
- High Efficiency: Performs multiple operations in mold cavities, runners, and root cleaning without frequent tool changes.
Applications
- Mold manufacturing
- Precision machining
- Aerospace industry
- Automotive industry
Technical Specifications
- Manufactured in accordance with ISO 7755-1984(E)
- Available in 12 models and 78 specifications
- Supports material processing, sample trial production, and non-standard customization
Usage & Maintenance
- Safety Protection: Always wear safety goggles and cut-resistant gloves to prevent debris splashing.
- Regular Cleaning: Remove residual chips promptly to maintain optimal cutting performance.
- Moderate Pressure: Excessive force can cause overheating or premature wear (reduced speed required for extended tools).
- Speed Control: Suitable for high-speed operation; adjust speed according to workpiece material (refer to recommended speed chart).
Application Case — Smoothing and Processing Weld Bead Excess
Scenario: Two thick steel plates are welded, forming a high and wide weld bead. The excess weld needs to be leveled flush with the base material.
Problem: Using a disc grinder often results in uneven pits, making it difficult to ensure overall flatness.
Solution:
- The technician selects a Type B double-cut rotary burr, using its flat end face to directly “mill” the top of the weld bead.
- Since the burr’s diameter is greater than the weld width, it easily grinds the weld flush with the base material, without creating dish-shaped pits.
- The cylindrical surface can then be used to refine the transition area between the weld and the base material.
Result:
- A flat, smooth weld surface
- More uniform stress distribution
- Significantly improved appearance quality
