How to Choose the Correct Plate Clamp

Handling steel plate safely requires the right lifting equipment for the job. Plate clamps are specifically engineered to grip, lift, and move steel plates, fabrications, and structural components without the need for welded lifting points or temporary rigging solutions. However, selecting the wrong clamp for the application can introduce serious safety risks — lifting direction, plate hardness, load weight, and surface condition must all be carefully considered before a clamp is chosen.

This guide sets out the key factors to work through when selecting a plate clamp, and explains how each decision contributes to a safe and compliant lift.

Why Correct Clamp Selection Is a Safety-Critical Decision

Plate clamps are safety-critical lifting devices. Unlike slings or shackles, they rely on an engineered cam-and-jaw mechanism that converts lifting force directly into clamping force — meaning the grip is only as reliable as the selection decision that preceded it. When the correct clamp is used for the application, loads remain securely gripped, plates can be lifted and rotated safely, and operations remain compliant with safe rigging practice. When the wrong clamp type, incorrect WLL, or inappropriate lift orientation is used, the consequences can include plate slippage, equipment failure, and risk to personnel.

The Selection Process

Work through the following seven steps in order. Each factor narrows the field of suitable clamps and ensures the final selection is matched to the specific demands of the lift.

Step	Factor	What to Consider
1	Determine the lift orientation	Establish whether the plate will be lifted vertically, horizontally, or both. Vertical clamps resist vertical load only. Universal clamps handle both orientations, including full 180° rotation. Horizontal clamps must always be used in pairs or more — never as a single clamp.
2	Confirm the plate weight and WLL	Determine total plate weight and how load distributes across the number of clamps. The selected clamp WLL must exceed the load applied to it. Never exceed the clamp's WLL. Keep sling lines at or close to vertical in the rigging configuration.
3	Check the minimum load requirement	Most vertical clamps require a minimum working load of 5–10% of rated WLL to ensure full cam engagement. If the plate falls below this threshold, the grip may be unreliable. Non-marring clamps carry no minimum load requirement.
4	Confirm the plate surface hardness	Standard clamps are rated to approximately 345HB. Wear-resistant grades — Hardox, Bisplate, Xar — are commonly 400–500HB and require a hard-material clamp such as the CrosbyIP IPU10H (rated to 450HB). Confirm hardness from the mill certificate — visual inspection alone is not reliable.
5	Assess surface condition and material type	Standard clamps require a clean, dry steel surface. Oil, grease, scale, or coating in the grip zone must be removed. For stainless steel, aluminium, painted plate, or glass, a non-marring clamp with polymer jaw inserts is required.
6	Evaluate plate size and load stability	Large or thin plates may flex over a long span — multiple clamps and a spreader beam may be required. Identify the centre of gravity before positioning clamps to avoid a tilting load placing unequal force on individual clamps.
7	Verify clamp condition before every lift	Inspect the clamp body, cam teeth, pivot ring, hoisting eye, and latch before each lift. Withdraw from service immediately if wear, cracking, deformation, or blunt cam teeth are found. Pre-use checks do not replace periodic thorough examination and recertification.

Quick Reference: CrosbyIP Plate Clamp Range

The following table summarises the CrosbyIP plate clamp models available from Cookes and their primary application criteria.

Model	WLL Range	Orientation	Max Hardness	Suited To
IPU10	0.5t – 6t	Universal (180°)	345HB	General purpose lifting, turning and transfer of standard structural steel plate
IPU10/A	1t – 2t	Universal (180°)	345HB	Auto-grip universal for confined spaces or difficult-access locations; engages automatically on placement
IPU10H	0.5t – 4.5t	Universal (180°)	450HB	Wear-resistant and abrasion-resistant plate: Hardox, Bisplate, Xar and equivalent grades
IPNM10P	0.5t – 2t	Vertical	No minimum	Stainless steel, aluminium, painted plate and glass where surface finish must be preserved; polymer jaw inserts
IPH10E	2t – 6t per pair	Horizontal only	345HB	Flat plate lifting and transfer in the horizontal plane; must always be used in pairs with a spreader beam
IPTKU	2t – 5t	Multi-angle	345HB	Steel beam lifting, lashing, and temporary tackle points during structural erection; hinged eye for variable load angles

Cookes Plate Clamp Solutions

Cookes is the authorised New Zealand distributor for CrosbyIP plate lifting clamps, supplying the full range to customers across structural steel fabrication, heavy engineering, tank and vessel construction, offshore and marine, and industrial manufacturing. Local stock availability, expert product selection advice, genuine spare parts, and inspection and recertification services are all available through Cookes branches nationwide.

To view the full range of CrosbyIP plate clamps available from Cookes, visit: cookes.co.nz/product-categories/lifting-rigging/material-handling-equipment/plate-clamps-grabs

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