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What is a C-Clamp?

Amy Radishofski
Amy Radishofski

A c-clamp derives its name from its appearance. This type of clamp may sometimes be called a "g-clamp," or, in Britain, its often called a "cramp." The main portion of the clamp is shaped like the letter "C" or a "G." One end of the "C" is flattened, while the other end has a hole drilled through it. A long threaded rod passes through the hole, usually considered to be the "top" of the c-clamp. The end of the threaded rod close to the other end of the "C" is also flattened. The two flattened ends are adjusted to hold the material to be clamped by turning a handle to secure the clamp.

C-clamps are usually made of cast iron or steel. The tool can be used in various ways, from holding two pieces of wood together while glue sets, to securing material for cutting or welding. Woodworking is the most common use for c-clamps. If the material being clamped can get scratched or marked easily, a protective layer should be added between the c-clamp and the material to reduce the chance of damage. When the clamp is closed, the protective layer absorbs the abuse, while the material it is protecting stays securely in place.

C-clamps may be found at flea markets.
C-clamps may be found at flea markets.

These clamps can come in numerous sizes to fit various project needs. For example, a larger heavy-duty c-clamp might be useful to a professional welder, while someone who enjoys woodworking as a hobby might only need a small four inch (10.16 cm) c-clamp. The price varies according to the type of clamp needed. Clamps are available at hardware stores, on the Internet, at garage sales, and even at the occasional flea market.

One drawback to the tool is the strength required to use it. To tighten and secure the clamp, the handle is turned manually. This can be a problem for those who suffer from arthritis or other dexterity issues. The shape of the clamp also limits how it can be used. A c-clamp must be placed on the edges of the material to be secured, since the curve of the "C" limits how deep the clamp can go. Alternatives to the c-clamp, such as bar clamps and vise grips, may be better suited for particular jobs.

C-clamps are not a new invention. They have been around for hundreds of years. In fact, antique clamps are collectibles that don't usually have a high price tag, even if they are from the 1800s or earlier.

Discussion Comments


@JimmyT - I haven't been able to find a way to make the process any quicker. It really is a pain.

Instead of using C clamps, I always use sliding clamps or hand claps when possible. It makes taking the clamps on and off much quicker. It seems like they are easier to control, too.


The thing I hate about using C clamps is the amount of time it takes to unscrew them and then rescrew them back on to the wood.

The projects I work on alternate between different thicknesses of wood, so I can't really keep a set of clamps at all of the different sizes I need. Does anyone have any suggestions to make the process quicker?

I have never seen then, and I don't know if they exist, but what I really need would be something like a bench clamp that was bolted to the work bench that I could put my project under and clamp it down quickly.


@Izzy78 - The C clamps that I bought came with covers for the top and bottom of the clamp surface. You might look around and see if you can buy some separately or else buy one more set of clamps that has them.

Like the article mentions, you could also put a piece of scrap wood between the clamp and your project. The scrap would could take the damage. Other than that, it just might be that you're tightening the clamp too much. Next time you use the clamps, just tighten them to the point where they are giving pressure but not digging into the wood. You may find you can still do what you need without having them tightened as far as the will go.


I just got into woodworking and bought a few C clamps to start with. I have used them a few times so far to clamp down pieces to my table while I am making cuts. The problem I'm having is that the clamps are leaving dents in the wood from the faces. Does anyone know how to fix this?

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    • C-clamps may be found at flea markets.
      By: JackF
      C-clamps may be found at flea markets.