Overview
The Martin H 1-1/4 split taper bushing is a standard MST® quick-disconnect (QD) bushing engineered for reliable power transmission coupling. The split barrel design with taper provides a true clamp on the shaft, making it ideal for connecting MST sprockets, sheaves, and coupling hubs to rotating shafts. This steel bushing accommodates a 1.25-inch finished bore with integral 1/4″ × 1/8″ keyway and delivers secure, repeatable mounting for industrial drive applications.
Key Features
- Easy to install and remove
- Keyed to both shaft and hub to help during blind installations
- Steel construction with 2,500 in-lb torque rating
- Split-barrel design with tapered cone grip ensures positive, no-slip engagement
- Solid flange for mounting to MST sprockets and hubs
- No external modifications required for drop-in replacement installations
Technical Specifications
| Bushing Size | H |
| Bore Diameter | 1.25 inches (finished with keyway) |
| Keyway Size | 1/4″ × 1/8″ |
| Flange Outer Diameter | 2.5 inches |
| Flange Thickness | 0.25 inches |
| Barrel Length | 1 inch |
| Barrel Diameter (Small End) | 1.57 inches |
| Barrel Diameter (Large End) | 1.625 inches |
| Bolt Circle Diameter | 2 inches |
| Number of Bolt Holes | 2 |
| Screw Thread Size & Length | 1/4-20 UNC × 3/4 inches |
| Screw Torque Specification | 95 in-lb |
| Torque Rating | 2,500 in-lb |
| Material | Steel |
| Weight | 0.75 lbs |
| Overall Length | 1.25 inches |
Typical Applications
The Martin H 1-1/4 MST bushing is widely used in:
- Belt drive systems with V-belt sheaves and pulleys
- Sprocket assemblies and power transmission chains
- Motor-to-shaft couplings requiring quick disconnection
- Automated machinery and material handling conveyors
- Industrial gearbox and reducer input/output shafts
- Equipment requiring periodic hub or sprocket removal without shaft dismount
Compatibility & Replacements
Compatible With
- MST® Sprockets – all standard Martin H-series sprocket bores
- MST® Sheaves and Pulleys – V-belt drive equipment
- HH1 and HCH1 Weld-On Hubs – Martin flange-mount hubs
- 1.25-inch finished-bore shafts with 1/4″ × 1/8″ keyway
- Industrial motors, pump shafts, and rotating equipment with matching bore diameters
Replaces / Drop-In Replacement For
The Martin H 1-1/4 directly replaces any existing MST® H-size bushing specification where a 1.25″ bore is required. This unit is interchangeable with previous Martin stock and inventory managed under the H 1 1/4 designation.
Works With
- Martin MST® power transmission product lines
- Standard 1/4-20 UNC fasteners (supplied with assembly)
- Conventional shaft coupling practices and mounting procedures
- Both blind and visual installation methods
