Guide: Talking turnbuckles – installation and usage

How to Use, Install and Apply Turnbuckles

A turnbuckle is a simple, often overlooked rigging device that can relieve a lot of pressure during difficult or critical lifts. Typically, Turnbuckles are used as a means of adjusting a load in cases of offset center-of-gravity. However, they are equally used to adjust the tension in cables chains, ropes and tie rods.

Turnbuckles are available in a wide range of sizes, from small units designed to tension fencing wire, through to turnbuckles, weighing several tons that form structural elements of large buildings.

In this blog will take a look at turnbuckle types, common applications, and installation instructions so you can get started utilizing this convenient tool.

Types

The most common turnbuckle types are eye and eye, hook and hook, jaw and jaw, jaw and eye, and hook and eye, each named for their combination of end fittings. The fittings are determined by what the turnbuckles need to connect to and whether the solution is permanent or temporary.

Eye and Eye

Each end of the eye and eye configuration has a closed-loop teardrop fitting, and it can be used almost anywhere. The eye and eye turnbuckle is designed to accept a shackle on each end, with the shackle pins passing through the turnbuckle eyes.

Hook and Hook

Because they are simple to connect and disconnect, hook end fittings are commonly used to make temporary connections. However, because the hook configurations lack a safety latch, they should never be used in connections where tension may unexpectedly release.

Jaw and Jaw

A jaw end fitting is made up of a U-shaped jaw and a bolt that are held together by a nut or pin. This configuration allows you to connect the sling or lifting lug to the turnbuckle directly. Furthermore, it is useful for connecting components that cannot be opened, such as an eye bolt.

Hook and Eye

Similar to hook and hook, the only difference in this configuration is that the eye end allows for one secure end attached to the rigging hardware.

Jaw and Eye

The jaw and eye configuration is almost identical to the eye and eye configuration, with the added flexibility of connecting directly to the lifting lug.Unless you have a fixed point or a lug that is difficult to work on a lift, this configuration isn’t as common.  

Turnbuckles are specified by:

Thread diameter: with larger threads able to carry higher loads. It should be noted however, that a 12 mm thread turnbuckle typically has a much lower load limit than a 12 mm eye bolt or a 12 mm diameter cable.

Take up is the total difference in length between the turnbuckle with the threads screwed all of the way in or out. Take up can be increased by attaching two or more turnbuckles in line.

End fittings may be eye bolts, hooks or shackles. Shackles may also be referred to as jaw end fittings. Many turnbuckles have an eye at one end and a shackle at the other. Toggle jaw end fittings allow rotation of the turnbuckle in any direction.

Working load limit should be carefully matched to the application. This is likely to result in turnbuckles with threads of larger diameter than that of cables and eye bolts in the tensioning system.

Turnbuckles are available in galvanized steel for most construction and industrial applications, as well as in stainless steel for use offshore, in critical applications or in exposed architectural features.

Applications and Industry Sectors

As previously stated, turnbuckles can be used to adjust and help equalise a load and correct an offset centre of gravity. For example, if you needed 12 ft 8 1/2 inches of total running length but didn’t have a sling of the appropriate size, you could install a turnbuckle to compensate by simply adjusting the turnbuckle in or out to get the desired length required for a perfectly level lift.Note: When adjusting turnbuckles, it is highly recommended that an appropriately sized wrench is used as opposed to a spud wrench or pry bar placed through the body. The latter tends to cause damage to the turnbuckle and could potentially create dangerous repercussions.

When a lift has six vertical pick points, a four-bar system may be required. It becomes difficult to ensure equal load distribution among the six points when this situation arises. Because you can put a sling on each of the four outside corners, you can put another bar on the two middle lugs and use a shorter sling with a turnbuckle. This will allow you to fine-tune the tension so that all six lugs are balanced.

Turnbuckles can be used for something as simple as a guard rail or clothesline, or as complex as a suspension bridge. 

Turnbuckles provide tension in the following industries:

Aircraft

Turnbuckles have been used in aircraft construction, especially during the early years of aviation. Historically, biplanes might use turnbuckles to adjust the tension on structural wires bracing their wings. Turnbuckles are also widely used on flexible cables in flight control systems. In both cases they are secured with lockwire or specifically designed wire clips to prevent them from turning and losing tension due to vibration.

Shipping

Turnbuckles are used for tensioning a ship’s rigging and lashings. This device is also known as a bottlescrew in this context.

Sports

Turnbuckles find common use to tension the ropes in professional wrestling rings and boxing rings, where they serve as the attachment between the ring ropes and ring posts. Rather than the usual bare metal, here the turnbuckles are covered with padding in order to protect participants and staff. Turnbuckles even play a part in professional wrestling where they are often dramatically used by participants as part of their offensive move set.

Entertainment industry

Turnbuckles are used in nearly all rigging performed in the entertainment industry, including theatre, film, and live concert performances. In entertainment rigging, turnbuckles are more commonly used to make small adjustments in line lengths. This is generally to make a flown unit sit parallel to the stage. Another way a turnbuckle could prove helpful is with making very minor height or angle adjustments.

Pipe systems

Turnbuckles are used in piping systems as a way to provide minor adjustments for field inconsistencies. This also allows for a minimum amount of resistance when transferring the load to the support components.

Orthopaedics

A type of splint is used for upper limb to produce gradual stretching over contracted joint by its turn buckle mechanism.

Installation

• Unscrew the end fittings from the body and extend them to the full take-up length.
• Connect either end fittings to the desired securement point.
• Loop the eye end fitting through the securement point it will be connected to.
• Loop the hook on a hook end fitting around whatever point it will be temporarily secured to.
• Unscrew the bolt from the jaw and position the securement point between the clevis ears for a jaw end fitting. Then insert the bolt and screw it shut.
• Turn the turnbuckle to bring the end fittings closer together until the desired rope or cable tension is reached.
• Tighten nuts, if applicable, all the way to the body.

At Hercules we stock a wide range of turnbuckles. For more information or to place an order give us a call: (877) 461-4876 or email your local branch.

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