McKissick M-491S Series Derrick Hoist Block - 12 Ton - 5/8 in Wire Rope - 14 in Sheave - Roll Forged

Description du produit

The McKissick M-491S Series Derrick Hoist Block is a heavy-duty rigging block engineered for high-capacity derrick and hoist applications in demanding industrial and oilfield environments. Rated at 12 tons, this configuration of the M-491S Series is built to handle substantial loads in derrick hoisting operations where structural integrity, bearing performance, and sheave durability are critical to safe and efficient continuous-duty service. The M-491S Series reflects McKissick's long-standing expertise in producing premium-grade hoist and derrick blocks for the most demanding segments of the rigging and lifting industry.

This block features a 14-inch sheave outside diameter and accommodates a maximum wire rope cable diameter of 5/8 inch. The sheave is roll forged, a manufacturing process that produces a denser, stronger grain structure compared to cast sheaves, resulting in superior resistance to wear, impact, and fatigue under the high-cycle, high-load conditions typical of derrick hoisting service. The 14-inch sheave diameter provides an excellent D:d ratio relative to the 5/8 inch cable, significantly reducing wire rope fatigue and extending rope service life under repeated load cycling. The block runs on sealed tapered roller bearings, which provide excellent radial and axial load capacity, reduced friction, and extended service life, with the sealed design protecting the bearing from contamination by dirt, moisture, and other environmental factors common in oilfield and heavy industrial environments.

The M-491S Series is designed for derrick hoist service where reliability under sustained heavy loads and repeated cycling is non-negotiable. The combination of a roll forged sheave and sealed tapered roller bearings represents a premium specification well-suited to continuous-duty hoisting applications in oil and gas, heavy construction, marine, and other industries where downtime is costly and equipment must perform consistently under pressure. As with all high-capacity rigging hardware, proper installation, regular inspection, and strict adherence to the rated working load are essential for safe operation.

Material:

Steel construction Roll forged sheave Sealed tapered roller bearings

Compatible With:

5/8 in maximum diameter wire rope cable Derrick hoisting systems High-capacity industrial and oilfield rigging configurations

Uses:

Derrick hoisting operations in oil and gas environments High-capacity industrial lifting and hoisting Heavy construction and civil engineering crane applications Marine and shipyard hoisting operations Continuous-duty high-cycle hoisting applications

Key Features:

12 ton working load capacity 14 in sheave outside diameter Maximum cable size: 5/8 in Roll forged sheave for superior wear and fatigue resistance Sealed tapered roller bearings for high-load performance and contamination protection Reduced maintenance requirements due to sealed bearing design M-491S Series — McKissick derrick hoist block line McKissick brand — established rigging hardware manufacturer