G-Clamp

A G-clamp, often called a C-clamp in North America, is a rigid, frame-style clamp with a threaded screw that closes against a fixed jaw. In a general workshop, it holds stock to a bench while you cut, drill or glue. In collision repair and frame straightening, heavier versions play a more demanding role. They grip sheet metal or frame rails securely enough to anchor a chain and apply a controlled pull. Few hand tools are asked to bear so much load in such a small package.

Why G-Clamps Matter in the Shop

When a vehicle has been in a collision, the structure often has to be pulled back to factory dimensions. A G-clamp designed for pulling gives a technician a strong attachment point on a rail, pinch weld or panel edge without welding a tab to the metal. Because the clamp can be repositioned quickly, it makes it easier to pull from different angles as the repair progresses. Outside body work, the same design is useful for fabrication, exhaust and bracket work, and for holding assemblies in place while tack welding.

What to Consider When Choosing a G-Clamp

• Throat opening: This is the distance between the screw and the frame of the clamp. A deeper throat lets you reach over flanges, around damaged areas and behind reinforcements. A smaller throat is lighter and easier to handle in tight spaces.
• Pulling capacity: Pulling clamps are commonly rated in tons. Match the rating to the work, and remember that the whole setup, including chain, shackle and anchor, is only as strong as its weakest link.
• Construction: Cast or forged heat-treated alloy steel resists spreading under load. A hardened screw and a swivel pad help the clamp seat securely without marring or slipping on the work surface.
• Attachment points: Multiple holes or a movable shackle allow a pull from several angles, which makes the clamp more versatile on complex damage.
• Condition and inspection: Check the screw threads, jaw and shackle pin regularly. Any bending, cracking or stripped threads mean the clamp should be retired.

Featured Brand in G-Clamps

Mo-Clamp is a name most collision repair technicians know. The company is regarded as an originator of the self-tightening clamp that uses a patented wedge pulling ring, and it has built a broad line of holding clamps, chain, anchoring tools and specialty collision repair accessories. Its G-clamp designs are aimed at professional body and frame work, with heat-treated steel construction, swivel pads and shackle options that make pulling at different angles more practical. Models such as the 5800 offer a 4-inch throat opening and a 5-ton rating, while the larger Jumbo style extends the throat to 7 inches for reaching behind more extensive damage.

Safe Use Tips

Always seat the clamp fully on clean, solid metal, and keep the pull in line with the clamp's design. Stand clear of the chain's path during a pull, use safety restraints where appropriate, and never exceed the rated capacity. Used correctly, a quality G-clamp is a dependable tool that can serve a shop for many years of repair work.