Turnbuckles Types and structure

Turnbuckles are used to take up slack and apply tension to a rigging assembly.

A turnbuckle is a device designed to alter applied tension slowly so that the cable/rope to which it is attached does not spin. This allows the turnbuckle to take up slack and apply tension to a rigging assembly.

Turnbuckles are usually made of internal screw threads along with a long sleeve at both ends, allowing them to be pulled together or pushed apart from twisting the central nut.

Turnbuckles Types

The primary types of turnbuckles used in rigging include:

Eye & eye turnbuckles

Hook & eye turnbuckles

Jaw & eye turnbuckles

Jaw & jaw turnbuckles

Types of End Fittings

Turnbuckles have three different types of end fittings designed for a specific purpose.

Eye end fitting – Used with other components, which can be opened and connected to the eye, such as a shackle or quick link. Eye end fittings have no moving parts and are the most cost-effective end fitting of the three. They are preferred in situations where the anchor point could possibly slip out of an open hook.

Jaw end fitting – Composed of a jaw, bolt, and nut, which are used to connect other components that can’t be opened, such as an eyebolt or swaged sling eye. Jaw end fittings are ideal to use with fixed anchor points, where it’s possible for the anchor point to come out of an open hook.

Hook end fitting – Temporarily connects components and can be conveniently attached and detached. They are ideal to use in situations where there is an easy and quick attachment and where the anchor point will not fall out of the opening of the hook. Hook end fittings are not recommended in situations where tension can suddenly release from the turnbuckle, causing the hook to dislodge.

All turnbuckles must be appropriately secured to prevent unscrewing during the lift or for long-term installations. Before securing a structure using a turnbuckle, you must know how to correctly size the turnbuckles, to ensure it can support the correct load weight.

Double check your fittings when using hook turnbuckles because the hooks are large and may not fit with other fittings having a similar working load limit.