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. |
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. |
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 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
