What is a Marble Clamp?
A marble clamp (often referred to as a slab lifting clamp or carry clamp) is a mechanical device used to grip and lift large, flat pieces of stone. Unlike standard wood clamps, these are engineered for gravity-assisted grip. They typically feature:
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Scissor Action: A mechanism that uses the weight of the stone to increase the clamping force.
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Rubber Lining: Vulcanized rubber pads that provide high friction while preventing the stone from scratching or chipping.
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Ergonomic Handles: Designed for two-person carries to distribute weight evenly and protect the back.
Key Types of Marble Clamps
Depending on the stage of the project—moving the slab or joining it—different clamps are required:
| Type | Purpose | Key Feature |
| Carry Clamps | Moving slabs manually between locations. | Sold in pairs; uses body weight to secure the grip. |
| Lifting Clamps | Attaching to a crane or forklift to move full slabs. | High weight capacity (often up to 1,000+ kg). |
| Seam Setters | Joining two pieces of stone (e.g., a countertop seam). | Uses suction cups and leveling dials for a flush finish. |
| Mitre Clamps | Holding 45-degree edges together while glue cures. | Ensures perfect 90-degree corners on "waterfall" edges. |
Why Use Specialized Clamps?
Using the wrong tool for stone is a recipe for disaster. Marble clamps provide three critical advantages:
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Safety: Carrying a 3 cm thick granite slab by hand is incredibly difficult. The polished surface offers no natural grip. Clamps provide a secure handle, reducing the risk of drops.
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Pressure Distribution: Stone is strong under compression but weak under tension. Marble clamps are designed to apply pressure evenly, preventing "point loading" that can cause a slab to crack.
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Efficiency: A pair of high-quality carry clamps allows two people to move pieces that would otherwise require four, saving time and labor costs.
Pro-Tips for Using Marble Clamps
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Keep it Clean: Dust and stone slurry can act like ball bearings between the clamp and the stone. Always wipe the contact points and the rubber pads before lifting.
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Check the Rating: Every clamp has a Working Load Limit (WLL). Never exceed it. A standard 2 cm marble slab weighs roughly 13lbs per square foot; always do the math before you lift.
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Vertical is Best: Most carry clamps are designed for vertical transport. Attempting to lift a slab horizontally ("flat") with a vertical clamp can cause the stone to snap under its own weight.
