MRO Today - Lift it right

Lift it right

by Clair D. Urbain

A chain, rope or cable is useless for lifting without the right hardware to attach it to a load.

With the wide variety of hooks, shackles, eye bolts, lifting rings and turnbuckles available, and with a little thought, you can select the correct combination to best match your job, according to the Specialized Carriers and Rigging Association (SCRA).

The SCRAs "Basic Rigging Training Manual" contains a wealth of information to help riggers complete lifts safely and efficiently. This article is based on information in this guide for safe, effective lifting and rigging. To obtain a copy, contact the Specialized Carriers and Rigging Association at or order online at www.scranet.org.

Hook selection and use
The hook should be selected to best work with the cable, chain or strap used in the lifting device. The hook should hold the load securely and safely.

Inspect the hook every time its used. If any part of the hook appears bent, strained, cracked or worn, take it out of service.

Heres what to look for:
Entire hook: Look for gouging, deep scratches or defects. Rigging hardware should not be painted or coated, which could hide signs of wear.

Latch: Check for distorted or bent hardware and/or a malfunctioning spring that doesnt keep the latch forced against the hook.

Saddle: Look for wear, cracks, corrosion and/or twisting anywhere along the saddle (outer edge) of the hook.

Throat: Check the gap space against the space specified by the hook manufacturer.

Connecting point: Check for cracks or wear.

Neck: Check for cracks, corrosion and twisting.

Shackle selection and use
Shackles are often used to connect a hook to a cable sling eye. It must be designed to work with the sling material. Anchor- or bow-type shackles are used with wire rope slings; chain shackles are used only with chain slings; synthetic slings or web slings need shackles with a wide bow to prevent sling crimping and premature wear.

Rigging shackles consist of a U-shaped shackle, spacers and a screw pin. Shackles that use a pin and cotter key instead of a screw pin to close the shackle are not recommended for rigging. Never replace the screw pin with a bolt.

Shackle size drives lifting capacity. The diameter of the bow, not the pin, governs the rated capacity. The shackle should be positioned so the load firmly seats on the screw pin and the bottom of the shackle. Use spacers to assure the chain hook or cable thimble stays centered on the shackle.

Cable slings may slide back and forth over the shackle pin and could unscrew it. In these cases, screw-pin shackles should not be used.

Inspect shackles with every use. Check for wear, cracks, chips or deformities in the crown. Inspect the pin for wear, straightness and proper seating. Make sure the shackle opening has not deformed and still meets manufacturer specifications. Finally, look for gouges, deep scratches or defects. Never paint or coat shackles.

If shackles are damaged, remove them from service.

Eye bolts selection and use
Dont use unshouldered eye bolts for lifting. Shouldered eye bolts are specifically designed for lifting, offering greater support when the rigging is at an angle to lift the load. If a load must be lifted with rigging at an angle to the load, use a swivel eye bolt or hoist ring.

To get the maximum lifting capacity from an eye bolt, lift the load straight up. You can lift loads more safely with a spreader beam and two eye bolts.

When using eye bolts, make sure at least 90 percent of the threads are engaged. Never alter the length of an eye bolt without engineering approval. Never weld, cut or modify an eye bolt.

Make sure the eye bolts shoulder fully contacts the load, and always use a shackle to connect the eye bolt to the rigging. Never connect the rigging hook directly to the eye bolt.

When not in use, remove eye bolts to prevent damage. If the eye bolt is permanently installed, it must be removed, inspected and reinstalled before lifting.

Select eye bolts based on the load weight and the angle of the pull on the bolt because capacity decreases as angle decreases.

Do not use any rigging assembly that results in a pull angle of less than 45 degrees. In these cases, use spreader bars or swivel eye bolts.

Inspect the eye bolt before use. Look for gouges, cracks, burrs or deformation anywhere on the eye bolt. If the threads are defective or dont fit the threaded hole, do not use it. Never paint or coat eye bolts because it can hide damage.

Lifting ring selection and use
Made of forged alloy steel, lifting rings are used to connect multi-part slings to a single connection point. Their ratings are based on straight pulls, so check the manufacturers specifications to make sure you size them correctly for angled-pull lifts. Generally, they maintain capacity at sling angles up to 60 degrees from the centerline of the pull.

Before using rings, inspect them for gouges, cracks, burrs or deformation. Dont coat or paint them; discard any ring that shows any type of damage.

Turnbuckle selection and use
Turnbuckles can adjust stress on slings and can help precisely balance a load during a lift. They must be made of a weldless alloy steel and offer a 5x load safety factor. They should be used for in-line pulls only.

For safety, use only one turnbuckle per leg on multi-leg slings. Make sure the threads on the end fittings are fully threaded through the centerpiece. Use a piece of wire to lash the end pieces so the turnbuckle cant unscrew under load.

Turnbuckles, like other rigging components, should not be used in lifts where the rigging is more than 60 degrees from the vertical position. Never side-load the turnbuckle or allow it to hit or touch any stationary object while under load.

Turnbuckles must be inspected before use and again as part of a routine rigging inspection program. Discard a turnbuckle if there are any cracks or deformations in the end fittings or the centerpiece. If the male or female threads are damaged or bent, discard the turnbuckle.