AGL0340405-JAW TO JAW TURN BUCKLE

What is a Jaw to Jaw Turnbuckle?

A Jaw to Jaw Turnbuckle (also commonly referred to as a Clevis-to-Clevis turnbuckle or closed-body rigging screw) is a heavy-duty, dual-threaded mechanical tensioning device featuring a U-shaped jaw (clevis) at both ends. Each jaw is equipped with a removable clevis pin and a secure locking mechanism (such as a cotter pin or a nut-and-bolt assembly).

Operating on the classic turnbuckle mechanic, it features one right-hand internal thread and one left-hand internal thread. When the central body is rotated, both jaws pull inward simultaneously to instantly eliminate slack and apply precise linear tension to a line, or push outward to release it.

Because the jaw end can wrap directly around a stationary pad eye, eye-plate, or anchor lug and lock into place with a pin, the Jaw to Jaw configuration provides the most secure, slip-free, and structurally stable connection type in the rigging industry.

Technical Features

• Dual Jaw (Clevis) End-Fittings: Features a U-shaped jaw at both ends, allowing it to easily straddle fixed plate lugs, eyelet brackets, or terminal structural links.
• Removable Pin Security: Jaws are secured with heavy-duty pins. Smaller industrial variants use a clevis pin with a cotter pin, while high-tonnage or permanent structural variants utilize a safety bolt with a hex nut and cotter pin to prevent the connection from ever shaking loose under vibration.
• Opposing Thread Configuration: Left-hand and right-hand thread pairing allows for step-less, micro-adjustable linear tensioning without twisting or spinning the attached cables, chains, or wire ropes.
• Drop-Forged Steel Construction: High-capacity variants are drop-forged from high-tensile carbon steel or alloy steel, compressing the grain structure to handle extreme tensile loads with a rigorous 5:1 structural safety factor.
• Open vs. Closed Body Choices: Available in an Open-Body style for quick visual checks of thread depth, or a Closed-Body (Pipe) style to fully encase and seal the threads against dirt, grit, and moisture.
• Industrial Finish Options: Typically hot-dip galvanized for standard heavy construction and outdoor weathering, or fabricated from Grade 316 Stainless Steel for clean, corrosive marine environments.

Primary Uses and Applications

Jaw to Jaw turnbuckles are strictly designed for straight, linear tensioning and are heavily preferred where components connect directly to fixed steel plates or structural weldments:

• Structural Steel & PEB Building Alignment: Connecting directly to fixed structural gusset plates and eye-lugs to adjust the tension and plumb-alignment of heavy structural columns, trusses, and Pre-Engineered Building (PEB) frameworks.
• Bridge and Canopy Suspension Systems: Serving as the central tensioning links for overhead stay-cables, tie-rods, and suspension lines on temporary footbridges or architectural canopies.
• Heavy Cargo Lashing & Tie-Downs: Securing high-tonnage industrial boilers, heavy military gear, and oversized transformers onto deck lashing points, railcars, or multi-axle trailers.
• Tower Crane & Mast Guy Wire Tensioning: Maintaining high, continuous tension on heavy structural guy wires used to stabilize tower cranes, transmission masts, and high-rise exhaust chimneys.
• Marine Mooring & Rigging Arrays: Deployed at ports, shipboards, and offshore oil platforms to securely tie down heavy equipment directly to deck-mounted D-rings or fixed pad eyes.

Key Advantages

• Elimination of Intermediate Hardware: Because the jaw fits directly over a welded plate lug or shackle eye, it completely eliminates the need for an intermediate rigging shackle, lowering overall equipment costs and reducing potential points of failure.
• Maximum Vibration Security: The safety-bolt or cotter-pin locking mechanism ensures that the terminal ends can never back out, unhook, or slip off, even when subjected to heavy continuous mechanical vibrations or severe road travel jolts.
• Zero Point-Loading Slip: Unlike a hook end which can slide or shift inside an anchor eye, the jaw pin locks cleanly along a straight axis. This forces the tension to pull directly along the true linear centerline of the turnbuckle, preventing twisting stresses.
• Precise Micro-Adjustability: Allows riggers to adjust tension down to millimeter accuracy, ensuring perfect load leveling when balancing heavy, multi-leg wire rope or chain bridles.
• High Structural Ductility: Because the components are drop-forged rather than cast, they will slowly yield or bend visually if subjected to catastrophic overloading beyond their capacity, giving supervisors a critical warning before a snap occurs.
• Excellent Thread Engagement Stability: Deep, industrial-cut internal threads provide massive surface contact area, completely resisting thread stripping under maximum rated lashing capacities.

Critical Safety & Operation Guidelines

⚠️ Linear Loading Only: Jaw to Jaw turnbuckles must strictly be subjected to straight line (axial) tension only. Side-loading, lateral twisting, or bending forces will distort the jaw ears or strip the internal barrel threads, causing immediate structural failure.

🔒 Thread Engagement Rule: During installation, ensure both threaded jaw shanks are inserted deep enough into the central body. At a minimum, the full diameter of the shank thread must be completely engaged inside the body barrel. Never over-extend a turnbuckle past its maximum rated take-up length.

 

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