KITO
Turnbuckles
Turnbuckles provide precise, adjustable tension control in straight‑line pulling applications—structural bracing, bridge cable tensioning, marine rigging, temporary works stabilisation, and heavy lifting assembly alignment. Constructed with a central body and two threaded end fittings (jaw, eye, or hook combinations), turning the body increases or decreases the overall assembly length, applying or relieving tension with fine control. The Crosby HG‑228 Jaw & Jaw Turnbuckle is the flagship heavy‑duty option, engineered with forged, quenched and tempered jaw ends, a hot‑dip galvanised body, modified UNJ threads for enhanced fatigue resistance, and a 5:1 design factor. Available from 5/16″ (800 lb WLL) to 2‑3/4″ (75,000 lb WLL), every Crosby turnbuckle is fatigue‑rated to 20,000 cycles at 1.5× WLL and conforms to ASME B30.26, ASTM F‑1145, and Federal Specification FF‑T‑791b.
Send an Enquiry
We'll get back to you on WhatsApp.
Trusted by Industry Leaders
Forged End Fittings for Fatigue Life
Quenched and tempered jaw and eye ends resist the crack initiation that plagues cast turnbuckle bodies, providing a predictable 20,000‑cycle fatigue life at 1.5× WLL.
Modified UNJ Thread Profile
The radius‑root thread form on end fittings eliminates the sharp stress concentration at the thread root that is the dominant fatigue crack initiation site, extending service life in dynamic applications.
Dual‑Jaw Positive Connection
Jaw & jaw configurations provide a clevis‑to‑clevis bolted connection that prevents rotation, misalignment, and accidental disengagement under reversing or fluctuating tension loads.
Hot‑Dip Galvanised Corrosion Protection
Full HDG coating of the body and end fittings ensures decades of atmospheric and marine exposure resistance without the chipping and peeling of paint‑based systems.
Fatigue‑Rated and Proof‑Tested
Every turnbuckle is proof‑loaded to 2.5× WLL and fatigue‑rated at 1.5× WLL for 20,000 cycles, providing documented load‑cycle performance data for engineered lift plans and structural designs.
Lock Nut Provision for Tension Retention
Lock nuts are available and recommended for all sizes, preventing the slow unthreading that can occur under vibration and eliminating the need for improvised wire‑locking or tack‑welding.
Turnbuckle Selection: Jaw vs. Eye vs. Hook Combinations
Jaw & jaw turnbuckles (Crosby HG‑228) provide a positive bolted clevis connection at both ends, making them the preferred choice for structural bracing and permanent installations where accidental disconnection is unacceptable. Eye & eye turnbuckles (Crosby HG‑226) terminate in closed eyes that accept shackles or pins, offering greater angular flexibility but requiring a secondary connector at each end. Hook & hook or jaw & hook combinations provide quick connection and release but introduce an open throat that can disengage under slack‑tension cycles; they should never be specified for overhead lifting applications. The fundamental selection rule: if the turnbuckle is in the load path of a suspended load, use only closed‑loop terminations (jaw‑jaw or eye‑eye) with secured pins.
Load Limitation: Straight‑Line Pull Only
Turnbuckles are rated exclusively for straight, in‑line tension. Side loading—even a few degrees off axis—generates bending moments in the threaded end fittings not accounted for in the Working Load Limit rating. When a turnbuckle is used to pull two misaligned attachment points together, the resulting angular load can reduce the safe working capacity by 50% or more and initiate fatigue cracking at the thread root. For applications where angular alignment cannot be guaranteed, the correct solution is to install a swivel or spherical bearing at one end of the turnbuckle, not to simply oversize the turnbuckle. Crosby technical guidance provides explicit angular misalignment limits for each size.