Rigging Blocks
Holloway Houston provides high-performance rigging blocks designed to change line direction and multiply pulling power. We stock an extensive inventory from McKissick, Crosby, and Yoke, featuring snatch blocks, trawl blocks, and wireline blocks with working load limits ranging from 1 ton up to 160 tons.
Rigging Blocks for Wire Rope, Chain, and Cable
A rigging block is a foundational tool in material handling, consisting of one or more sheaves (grooved wheels) protected by a sturdy frame or "shell." By allowing wire rope, synthetic line, or chain to pass around the sheave, the block redirects the path of the line. This mechanical change allows operators to navigate obstacles, create complex , or generate significant mechanical advantage to lift loads far exceeding the raw capacity of a single winch.
At Holloway Houston, our blocks are sourced from world-class manufacturers like McKissick and Crosby, ensuring every unit meets the rigorous standards of ASME B30.26. Whether you are looking for a lightweight hay fork pulley for agricultural use or a heavy-duty tilt-up wall block for oilfield well intervention, our 65 years of rigging expertise ensures you get the right tool for the job.
The Physics of Redirection
When a line passes through a block, the block itself becomes a load-bearing point that must withstand the "resultant friction" and the tension of both the lead and load lines. This is why selecting a block based on its Working Load Limit (WLL) is critical. A block at a 90-degree angle of redirection experiences 1.41 times the line pull in stress. Holloway Houston specialists assist clients in calculating these resultant forces to ensure that every block in the assembly is rated for the true operational tension.
Types of Rigging Blocks Available at Holloway Houston
Different industrial applications require specific block architectures. Below are the primary categories maintained in our Houston inventory.
Snatch Blocks
The snatch block is the most versatile tool in the rigger's kit. Its defining feature is a side plate that opens, allowing a rope to be seated on the sheave without needing to thread it from the end. This is ideal for field recoveries or adding a pull point to an existing line. We stock the McKissick #420 and #418 models, rated at 15 tons, alongside Yoke snatch blocks ranging from 2 to 20 tons. These blocks often feature swivel hooks or shackles for secure attachment to fixed points.
Trawl Blocks
Engineered for the brutal, high-cycle environments of commercial fishing and marine operations, trawl blocks are built for continuous line travel. The McKissick 452 12-inch double-rig block is a staple for net hauling and offshore cable laying, offering 10-ton capacity and specialized swivel eye fittings to prevent line twisting. These blocks are designed to resist the corrosive effects of saltwater while maintaining smooth sheave rotation under constant load.
Wireline and Tilting Blocks
In the oil and gas sector, precision is paramount. Wireline blocks guide small-diameter cables during well intervention and pump-down operations. Our McKissick TU484 and TU483 tilt-up wall blocks are designed to handle high-tension wireline runs, with some specialized models reaching capacities up to 160 tons. These allow for horizontal line entry when wall-mounted, providing stability during high-pressure runs.
Super Champion Blocks
For heavy-duty crane work and construction rigging, the Crosby Super Champion series represents the peak of forged durability. Models like the Crosby 430 and 434 handle loads between 20 and 25 tons, featuring oversized sheaves (up to 10 inches) to reduce bending stress on large-diameter wire ropes.
Hay Fork Pulleys
For lighter utility and agricultural tasks, Holloway Houston carries hay fork pulleys. These are typically rated for 1-ton loads and are used in barn lofts or small workshops. While lighter in capacity, they still follow the same manufacturing integrity as our industrial lines, providing a safe solution for overhead lifting in non-industrial settings.
Technical Specifications: Capacity, Sheave Size, and Fitting Type
Selecting the correct block requires a precise match between your equipment and the intended load. Holloway Houston categorizes blocks based on four primary technical variables:
1. Working Load Limit (WLL)
Our catalog covers the full spectrum of industrial needs:
- Light Duty (1 Ton) : Agricultural hay fork pulleys from Yoke and McKissick.
- Medium Duty (2 – 20 Tons) : Standard snatch blocks and Super Champion crane blocks.
- Heavy Duty (30 – 160 Tons) : Specialized wireline and tilt-up blocks for well service.
2. Sheave Diameter and Rope Compatibility
Sheave size is critical for rope longevity. A sheave that is too small for the rope diameter causes "fatigue cycles," leading to premature wire rope failure. We offer sheave sizes from 3 inches to 16 inches, compatible with everything from 10mm synthetic lines to 1-1/2 inch heavy-duty wire rope. The groove of the sheave must also match the rope diameter to prevent the rope from flattening or "pinching," which destroys the core of a .
3. Attachment Fittings
How a block connects to your system determines its mobility:
- Swivel Hooks : The most common fitting, allowing the block to rotate and align with the load path.
- Swivel Eyes : Provides a permanent, rotating connection point for shackles or bolts.
- Fixed Bail : Often seen on wall-mounted tilt-up blocks for a rigid, stationary installation.
- Shackle Fittings : Common on snatch blocks for secure, semi-permanent attachment to anchor points.
Our Brands: McKissick, Crosby, and Yoke
Holloway Houston is a premier authorized distributor for the most trusted names in the global rigging industry. We provide engineered solutions backed by the metallurgical excellence of these manufacturers.
McKissick (A Crosby Brand)
McKissick is the cornerstone of our block inventory. Known for their "Performance Rated" engineering, McKissick blocks are 100% forged and feature high-cycle bearings designed for longevity. From the agricultural HF series to the massive TU-series tilt-up blocks used in offshore well intervention, McKissick products are the standard for durability. Their snatch blocks, like the 418 and 420 series, are recognized worldwide for their safety-locked side plates and integrated grease fittings.
Crosby Super Champion
The Crosby name is synonymous with heavy-lift integrity. The Super Champion series (Models 430 and 434) is specifically designed for the most demanding crane and construction applications. These blocks feature flame-hardened sheaves and high-strength alloy components, allowing them to handle the aggressive friction and heat generated during 20-ton and 25-ton lifts.
Yoke Rigging
Yoke provides a robust range of snatch blocks and hay fork pulleys that offer an exceptional balance of cost-efficiency and safety. Yoke’s 8-series snatch blocks are widely utilized in the towing and recovery industries, providing reliable mechanical advantage in capacities ranging from 2 to 20 tons. Every Yoke block we stock is rigorously tested and individually marked.
Rigging Block Applications by Industry
Rigging blocks from Holloway Houston are deployed across the globe in the following sectors:
- Construction : Used to navigate tight urban job sites or add mechanical advantage to structural steel lifts.
- Oil and Gas : Vital for well intervention and wireline services where tension control is critical. Tilt-up blocks are specifically designed for the floor or wall mounting required in these high-pressure environments.
- Marine & Offshore : Trawl blocks handle repetitive cycling for net hauling and deck rigging on construction vessels.
- Mining : Redirecting wire rope in headframes and underground material handling systems where wire rope must navigate sharp angles around gallery corners.
- Agriculture : Utilizing hay fork pulleys for overhead storage and material movement in barn and loft settings.
Selection Guide: How to Choose the Right Block
When consulting with a Holloway Houston rigging specialist, please have the following information ready to ensure a safe match:
- Total Resultant Load : Remember that the load on the block's fitting is not just the weight of the object. It is the sum of the tension on all lines passing through the block.
- Rope Material : Are you using synthetic lines? Wire rope requires harder sheave materials to prevent grooving.
- Bending Ratio (D/d) : The ratio of the sheave diameter (D) to the rope diameter (d) is essential. A higher ratio ensures the wire rope does not fatigue as quickly.
- Environment : Offshore or coastal applications may require galvanized finishes or stainless steel components to prevent corrosion from salt spray.
Safety, Inspection, and Maintenance
Because blocks contain moving parts and bearings, they require more frequent maintenance than static hardware like.
- Groove Inspection : Check sheaves for "corrugation" or wear. If a sheave groove becomes too narrow, it will pinch the rope, leading to rapid degradation of the outer wires.
- Side Plate Integrity : On snatch blocks, ensure the locking pin or latch is fully engaged before every lift. A partially closed block can "butterfly" open under load, dropping the line.
- Lubrication : Most professional-grade McKissick blocks feature grease fittings. Regular lubrication of the center pin and bearings is mandatory for high-cycle trawl and wireline work.
- ASME Compliance : Conduct periodic inspections according to ASME B30.26. Any block showing visible deformation of the side plates or a 10% reduction in fitting dimensions should be removed from service.
Frequently Asked Questions
A snatch block features an openable side plate. This allows you to place the rope directly over the sheave without having to thread the entire length of the cable from the end. It is the preferred choice for field rigging and vehicle recovery.
We stock a range from 1-ton light utility pulleys up to 160-ton heavy wireline tilt-up blocks. Standard industrial snatch blocks typically range from 2 to 20 tons.
It depends on the sheave. While possible, wire rope sheaves are often made of harder steel that can have tiny burrs. These burrs will quickly shred synthetic or natural fibers. For synthetic rope, a dedicated "fiber rope" block with a smooth sheave is recommended.
The load on the block depends on the angle of the pull. If the rope goes in and out parallel (180-degree turn), the load on the block is twice the line tension. At a 90-degree angle, the load is 1.41 times the tension. Always consult a for accuracy.
The primary standard is ASME B30.26, which covers design, marking, inspection, and maintenance. In construction environments, OSHA 29 CFR 1926.251 also applies.
Every time wire rope bends over a sheave, it experiences stress. A larger sheave diameter (relative to the rope's diameter) reduces this bending stress, significantly extending the service life of your wire rope slings.
Complete Your Rigging System
- Rigging Shackles — Connect blocks to anchor points, crane hooks, and rigging assemblies with anchor and chain shackles.
- Wire Rope Slings — Pair with blocks to build complete wire rope rigging and block-and-tackle systems.
- Shank Hooks — Hook-to-hook and hook-to-block connections for crane and rigging systems.
- Coupling Links and Master Links — Complete multi-leg sling assemblies with master links and sub-links for use above block systems.