Crosby McKissick M-491 / G-491 Tower / Derrick Hoist Blocks

New design provides the dependability of standard McKissick® Snatch Blocks, along with features that make it perfect for the challenging needs of Tugger Hoist and Tower Erection applications.

  • A wide variety of configurations:
    – 4, 8, 12, 15, 25 or 30 metric ton capacity
    – 3/8″, 7/16″, 1/2″, 9/16″, 5/8″, 7/8″, 1″ and 1-1/4″ wire line sizes
    – Painted or Galvanized finish
  • 8″ and 10″ blocks furnished with dual rated wireline sheaves.
  • Forged steel swivels, tees, yokes and shackles are Quenched & Tempered.
  • Sheave lubrication through center pin for easy maintenance.
  • Design factor of 4 to 1.
  • All blocks 14″ and larger are furnished with McKissick® Roll ForgedTM sheaves with flame hardened grooves.
  • Recessed sideplate design reduces the gap between the sheave rim and the sideplate, allowing the sheave assembly to be captured in the block if loss of center pin occurs.
  • Sealed tapered roller bearings extend the life of the center pin and bearings, and allows for faster line speeds than recommended with standard snatch blocks.
  • Shackle fitting swivels for easy positioning.
  • Suitable for hoisting personnel, contingent upon all employees, including the winch operator, being trained to follow any applicable Federal, local and industry standards.
    – Tugger / Derrick applications: API RP54
    – Tower applications: OSHA directive CPL 2-1.36
  • Holes through side plates are available for secondary block securement device.
  • Manufactured by an API Q1 Certified facility.
  • Type Approval and certification in accordance with ABS 2006 Steel Vessel Rules 1-1-17.7, and ABS Guide for Certification of Cranes.
  • All sizes are RFID EQUIPPED.
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M-491 / G-491 Tower / Derrick Hoist Blocks Types

M-491 / G-491 Tower / Derrick Hoist Blocks Specs

* Ultimate Load is 4 times the Working Load Limit.




Crosby is the world leader in rigging, lifting, and material handling hardware. We set the standard for quality, training, and technical expertise in the field.

The Crosby Group was the first to:

  • Produce the forged wire rope clip (1880s)
  • Produce wire rope guards on sheaves that can be opened for easy reeving (1925)
  • Forge load rating (working load limit) directly onto product (1958)
  • Quench and temper fittings for more reliable performance (1973)
  • Forge Product Identification Code (PIC) into each product that allows traceability to its respective date of production and material certification (1977)
  • Rate products as Fatigue Rated (1991)
  • Forge patented QUIC-CHECK™ markings into hooks, shackles, and various other rigging products to assist users in determining proper use (1992)
  • Produce a crane block that can be reeved without removing the wedge socket from wire rope in the United States (1996)
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All product warnings: Warnings Page