Overview
The Martin AK51 1 1/8 is a precision-machined, fractional horsepower (FHP) V-belt pulley designed for light-duty power transmission applications. Manufactured by Martin Sprocket & Gear, this single-groove sheave combines robust cast iron construction with finished bore design for direct bolt-on installation. The pulley is built to ARPM industry standards and excels in HVAC systems, fans, blowers, and other equipment requiring dependable torque transfer at modest speeds.
Key Features
- Cast Iron Construction: Manufactured from class 30 gray iron with 30000 tensile strength and maximum speed of 6500 fpm, providing durability in continuous-duty applications.
- Precision Groove Design: Precision machined grooves ensure proper belt engagement and reduced slip.
- Static Balancing: All Martin sheaves are statically balanced for smooth, vibration-free operation.
- Finished Bore with Keyway: Ready-to-install design eliminates custom machining; includes 1/4″ × 1/8″ keyway for secure shaft connection.
- Multi-Belt Compatibility: Accommodates 3L, 4L, and A belt sections, providing flexible drive system options.
Technical Specifications
- Bore Diameter: 1-1/8″ (finished)
- Outside Diameter: 4.95″
- Number of Grooves: 1
- Pitch Diameter: 4.36″ (3L section) / 4.7″ (4L & A section)
- Face Width: 3/4″
- Material: Cast Iron (Class 30 Gray Iron)
- Keyway Size: 1/4″ × 1/8″
- Pulley Construction: Webbed Hub
- Belt Sections: 3L, 4L, A
- Maximum Speed: 6,500 fpm
- Mounting Type: Finished Bore (no bushing required)
- Weight: Approximately 1.7 lbs
Typical Applications
The Martin AK51 1 1/8 is ideal for:
- HVAC equipment (fans, blowers, compressors)
- Portable and stationary machine tools
- Agricultural grain augers and conveyors
- Light industrial motors and pumps
- Material handling equipment requiring low to moderate horsepower
Compatibility & Replacements
Compatible With
- 3L, 4L, and A section classical V-belts
- Motors up to 3 horsepower (typical FHP range)
- Standard 1-1/8″ bore shaft equipment
- HVAC systems and OEM machinery
Replaces / Drop-In Replacement For
This AK51 Pulley 1-1/8″ bore is directly interchangeable with other manufacturers, including competitive brands such as Gates, Moline, Maska, Maurey, and Goodyear equivalent AK-series pulleys. Verify your specific OEM part number before ordering for guaranteed fit.
Works With
- Classical V-belt drive systems (no serpentine or synchronous belts)
- Standard shaft couplings and keystock hardware
- Pillow block and flange-mount bearings
- Fixed-speed and step-pulley transmission systems
