Overview
The Martin SK-1-1/2 quick disconnect bushing is a precision-engineered shaft coupling component for mounting pulleys, sprockets, and sheaves on 1.5-inch diameter shafts. Built from cast iron and designed with a split flange and tapered bore, this QD bushing delivers strong, vibration-resistant clamping. The integral 3/8″ × 3/16″ keyway and set screw design prevents shaft rotation and keeps the key secure under load, making it ideal for automotive, agricultural, construction, and industrial machinery applications where reliable power transmission is critical.
Key Features
- 1.5-inch finished bore—direct fit for standard drive shafts
- Split flange and tapered design for strong shaft clamping without slippage
- Cast iron construction offers superior wear and corrosion resistance
- Integral 3/8″ × 3/16″ keyway with set screw prevents key migration on vibrating loads
- Three evenly spaced bolt holes for secure flange mounting (5/16-18 threads, 3-5/16″ bolt circle)
- 180 in-lb screw torque rating for consistent, repeatable assembly
Technical Specifications
- Bore Diameter: 1.5 inches
- Barrel Diameter: 2.812 inches
- Flange Outside Diameter: 3.875 inches
- Flange Thickness: 0.5625 inches
- Length Through Bore: 1.9375 inches
- Barrel Length: 1.375 inches
- Material: Cast Iron
- Keyway Size: 3/8″ × 3/16″
- Bolt Circle Diameter: 3-5/16 inches
- Number of Bolt Holes: 3
- Screw Thread Size: 5/16-18
- Screw Length: 2 inches
- Screw Torque Rating: 180 in-lb
Typical Applications
Martin SK-1-1/2 bushings are widely used across industrial power transmission systems including:
- Automotive drive shafts and transmission components
- Agricultural equipment and machinery
- Construction and heavy equipment
- Conveyor and material handling systems
- Industrial pump and motor coupling
- Home appliances and small machinery
Compatibility & Replacements
Compatible With
- Any 1.5-inch diameter shaft with standard taper bore mounting
- Martin-compatible pulley, sprocket, and sheave designs (SK series hub bores)
- Standard 5/16-18 mounting hardware and fastening systems
- Drive systems rated for 180 in-lb assembly torque
Replaces / Drop-In Replacement For
- Martin SK 1 1/2 (direct equivalent)
- Other SK-series 1.5-inch bore quick disconnect bushings with identical flange geometry and keyway specifications
Works With
- Martin pulleys and sprockets with SK hub bore designations
- Standard industrial V-belt and synchronous belt drives
- Chain sprocket systems for power transmission
- Sheave assemblies for belt drive applications
