Shop by Category

  • Ag Bearings
  • Inserts
  • Roller Chain
  • Belts
  • Taper Roller Bearings
  • Housed Units
  • Bushings
  • Couplings
  • Sheaves
  • Sprockets
  • Tools

    • Shop by Brand

  • Timken
  • Martin
  • Gearwrench
  • Crescent
  • View all Brands
  • Martin - Quadra-Flex® Type J Coupling Flange

    • Martin - Quadra-Flex® Type J Coupling Flange

    Martin

    SKU:
    QFJ-4J-20MM

    Product Description

    Martin - Quadra-Flex® Type J Coupling Flange

    Martin Sprocket & Gear — 57 Configurations

    Overview
    Specifications
    Applications

    Martin couplings connect rotating shafts while accommodating misalignment, absorbing shock loads, and dampening vibration between the driver and driven equipment. Whether you’re connecting a motor to a pump, gearbox to a conveyor, or any other power transmission application, the right coupling protects both components from the forces that cause premature bearing failure, shaft fatigue, and seal leaks.

    Martin Sprocket & Gear has been manufacturing couplings and power transmission components in the USA since 1928. Their coupling line includes jaw couplings, Quadra-Flex® elastomeric couplings, and gear couplings — each designed for specific torque ranges, misalignment tolerances, and operating conditions.

    Available in 57 configurations (QFJ-3J-PB, QFJ-3J-3/8, QFJ-3J-11MM, QFJ-3J-12MM, QFJ-3J-1/2 and 52 more) for professional power transmission applications.

    • Misalignment Accommodation — handles angular, parallel, and axial shaft misalignment
    • Shock Absorption — elastomeric elements dampen vibration and protect connected equipment
    • Easy Maintenance — replace flex elements without moving motors or driven equipment
    • Multiple Bore Options — available in standard and metric bore sizes with keyways
    • USA Heritage — Martin Sprocket & Gear, manufacturing since 1928
    Martin Sprocket & Gear Warranty — Martin products are warranted against defects in material and workmanship. Contact us for warranty claims and replacement.
    SKUSizeBoreTypeElement
    3J - 78 in-lb - 9,200 RPM (12)
    QFJ-3J-PB3J - 78 in-lb - 9,200 RPMPilot BoreType JHytrel Element
    QFJ-3J-3/83J - 78 in-lb - 9,200 RPM3/8" - 0.38in - 9.52mmType JHytrel Element
    QFJ-3J-11MM3J - 78 in-lb - 9,200 RPM11mm - 0.43inType JHytrel Element
    QFJ-3J-12MM3J - 78 in-lb - 9,200 RPM12mm - 0.47inType JHytrel Element
    QFJ-3J-1/23J - 78 in-lb - 9,200 RPM1/2" - 0.50in - 12.70mmType JHytrel Element
    QFJ-3J-14MM3J - 78 in-lb - 9,200 RPM14mm - 0.55inType JHytrel Element
    QFJ-3J-15MM3J - 78 in-lb - 9,200 RPM15mm - 0.59inType JHytrel Element
    QFJ-3J-5/83J - 78 in-lb - 9,200 RPM5/8" - 0.62in - 15.88mmType JHytrel Element
    QFJ-3J-16MM3J - 78 in-lb - 9,200 RPM16mm - 0.63inType JHytrel Element
    QFJ-3J-19MM3J - 78 in-lb - 9,200 RPM19mm - 0.75inType JHytrel Element
    QFJ-3J-3/43J - 78 in-lb - 9,200 RPM3/4" - 0.75in - 19.05mmType JHytrel Element
    QFJ-3J-7/83J - 78 in-lb - 9,200 RPM7/8" - 0.88in - 22.22mmType JHytrel Element
    4J - 156 in-lb - 7,600 RPM (14)
    QFJ-4J-PB4J - 156 in-lb - 7,600 RPMPilot BoreType JHytrel Element
    QFJ-4J-1/24J - 156 in-lb - 7,600 RPM1/2" - 0.50in - 12.70mmType JHytrel Element
    QFJ-4J-14MM4J - 156 in-lb - 7,600 RPM14mm - 0.55inType JHytrel Element
    QFJ-4J-15MM4J - 156 in-lb - 7,600 RPM15mm - 0.59inType JHytrel Element
    QFJ-4J-5/84J - 156 in-lb - 7,600 RPM5/8" - 0.62in - 15.88mmType JHytrel Element
    QFJ-4J-16MM4J - 156 in-lb - 7,600 RPM16mm - 0.63inType JHytrel Element
    QFJ-4J-19MM4J - 156 in-lb - 7,600 RPM19mm - 0.75inType JHytrel Element
    QFJ-4J-3/44J - 156 in-lb - 7,600 RPM3/4" - 0.75in - 19.05mmType JHytrel Element
    QFJ-4J-20MM4J - 156 in-lb - 7,600 RPM20mm - 0.79inType JHytrel Element
    QFJ-4J-7/84J - 156 in-lb - 7,600 RPM7/8" - 0.88in - 22.22mmType JHytrel Element
    QFJ-4J-15/164J - 156 in-lb - 7,600 RPM15/16" - 0.94in - 23.81mmType JHytrel Element
    QFJ-4J-24MM4J - 156 in-lb - 7,600 RPM24mm - 0.94inType JHytrel Element
    QFJ-4J-25MM4J - 156 in-lb - 7,600 RPM25mm - 0.98inType JHytrel Element
    QFJ-4J-14J - 156 in-lb - 7,600 RPM1" - 1.00in - 25.40mmType JHytrel Element
    5J - 312 in-lb - 7,600 RPM (9)
    QFJ-5J-PB5J - 312 in-lb - 7,600 RPMPilot BoreType JHytrel Element
    QFJ-5J-1/25J - 312 in-lb - 7,600 RPM1/2" - 0.50in - 12.70mmType JHytrel Element
    QFJ-5J-5/85J - 312 in-lb - 7,600 RPM5/8" - 0.62in - 15.88mmType JHytrel Element
    QFJ-5J-3/45J - 312 in-lb - 7,600 RPM3/4" - 0.75in - 19.05mmType JHytrel Element
    QFJ-5J-7/85J - 312 in-lb - 7,600 RPM7/8" - 0.88in - 22.22mmType JHytrel Element
    QFJ-5J-15/165J - 312 in-lb - 7,600 RPM15/16" - 0.94in - 23.81mmType JHytrel Element
    QFJ-5J-15J - 312 in-lb - 7,600 RPM1" - 1.00in - 25.40mmType JHytrel Element
    QFJ-5J-1-1/165J - 312 in-lb - 7,600 RPM1-1/16" - 1.06in - 26.99mmType JHytrel Element
    QFJ-5J-1-1/85J - 312 in-lb - 7,600 RPM1-1/8" - 1.12in - 28.57mmType JHytrel Element

    Where Martin Couplings Connect the Drive

    • Pump Systems — motor-to-pump connections on centrifugal, positive displacement, and submersible pump drives
    • Conveyor Systems — motor-to-gearbox and gearbox-to-head-shaft connections on belt and roller conveyors
    • Agricultural Equipment — irrigation pumps, grain handling drives, and PTO-to-implement connections
    • HVAC Systems — fan drives, chiller compressors, and cooling tower motors
    • General Industrial — mixers, agitators, generators, and any motor-to-load connection requiring misalignment accommodation

    1 All dimensions follow the Lambear tri-format: Imperial fraction – Decimal inches – Metric (mm).

    2 Specifications are catalog values. Contact us for application-specific recommendations.

    Product Videos

    Custom Field

    Product Reviews

    Recommended