Overview
The Martin 3B66SD is a three-groove quick-detachable (QD) sheave manufactured to transmit power in multi-belt industrial drive systems. With 6.95 inches outside diameter, this cast-iron pulley accommodates A, 4L, B, and 5L V-belt profiles and uses a standard SD quick-change bushing for rapid installation and bore changes across standard shaft sizes.
Key Features
- Three-groove design — Supports balanced three-belt power transmission in compact applications
- QD quick-detachable bushing — Eliminates need for multiple fixed-bore units; change bore sizes without replacing the entire sheave
- Cast-iron construction — Dynamically balanced at the factory for smooth, vibration-free operation
- Phosphate and paint finish — Corrosion resistance for indoor and light-duty outdoor environments
- Multi-belt compatibility — Works with A, 4L, AX, B, 5L, BX, AA, and BB belt profiles
- SD bushing required — Bore range: 1/2″ to 1 15/16″ (SD bushing sold separately)
Technical Specifications
- Model Number: 3 B 66 SD
- Manufacturer: Martin Sprocket & Gear
- Groove Type: 3-Groove (B Section)
- Outside Diameter: 6.95″
- Belt Compatibility: A (4L), B (5L), AX, BX, AA, BB
- Bushing Type: SD Quick-Detachable
- Bore Range: 1/2″ to 1 15/16″
- Weight: 10–12 lbs (with bushing)
- Material: Gray cast iron
- Finish: Phosphated and painted
- Dynamic Balance: Factory balanced
Typical Applications
The Martin 3B66SD is commonly used in:
- Multi-belt industrial drive systems
- Machinery requiring compact three-groove transmission
- Systems needing rapid bore changes without sheave replacement
- HVAC, conveyor, pump, and fan drive applications
- Original equipment manufacturing (OEM) and field repairs
Compatibility & Replacements
Compatible With
- SD quick-detachable bushings (sold separately)
- A (4L), B (5L), AX, BX, AA, and BB V-belt profiles
- Multi-belt drive systems with standard industrial shafts
- Martin and non-Martin power transmission systems
Replaces / Drop-In Replacement For
- Browning 3B66SD
- TB Woods 663B and 6.6 3B SD
- Continental 6.6-3B-SD
- Dodge 3B66 SD
- Other standard 6.95″ OD three-groove QD sheaves
Works With
- SD quick-detachable bushings (multiple bore sizes available)
- Any A, 4L, B, 5L, AX, BX, AA, BB V-belt
- Standard industrial shaft mounting systems
