McKissick M-491S Series Derrick Hoist Block - 30 Ton - 1-1/4 in Wire Rope - 20 in Sheave - Roll Forged

Product Description

The McKissick M-491S Series Derrick Hoist Block is a premium heavy-duty block engineered for the most demanding derrick hoisting and oilfield lifting applications where maximum load capacity, bearing performance, and long-term reliability are critical. Rated for a 30-ton working load, this block accommodates up to 1-1/4 in wire rope and features a 20 in outside diameter roll forged sheave fitted with sealed tapered roller bearings, delivering superior load-carrying efficiency, reduced friction, and extended bearing service life compared to bushing-type designs. The sealed bearing configuration protects internal components from contamination, moisture, and debris in harsh field environments, significantly reducing maintenance requirements and unplanned downtime.

The roll forged sheave construction provides enhanced strength, fatigue resistance, and surface hardness relative to cast alternatives, making it well suited for high-cycle derrick operations where rope and sheave wear are primary concerns at elevated load ratings. The 20 in sheave diameter, combined with the 1-1/4 in rope capacity, is engineered to maintain favorable rope-to-sheave diameter ratios that extend wire rope service life under sustained heavy loads. The M-491S Series is designed to perform reliably in oilfield, offshore, and heavy construction derrick systems where continuous-duty hoisting at high capacity is required.

McKissick's M-491S Series represents a top-tier offering within their derrick block product family, combining roll forged sheave technology with sealed tapered roller bearings to meet the demands of the most rigorous hoisting environments. These blocks are commonly specified by drilling contractors, offshore rig operators, heavy lift engineers, and rigging professionals who require a dependable, low-maintenance hoist block for critical 30-ton rated lifting operations.

Material:

Steel shell and frame construction (confirm specific alloy and finish with manufacturer documentation) Roll forged sheave Sealed tapered roller bearings

Compatible With:

1-1/4 in wire rope Derrick hoisting systems

Uses:

Derrick hoisting and lifting operations Offshore and onshore oilfield drilling and workover rig applications Heavy construction crane and derrick systems High-cycle heavy-capacity industrial hoisting

Key Features:

30 Ton capacity 1-1/4 in maximum cable diameter 20 in sheave outside diameter Roll forged sheave construction Sealed tapered roller bearings M-491S Series construction

Note:

Confirm material finish, certifications, working load limit documentation, and sheave material specifications directly with McKissick or an authorized distributor before specifying for a particular application.