A C-clamp or G-clamp or G-cramp is a type of
clamp device typically used to hold a
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of ligni ...
or
metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typi ...
workpiece, and often used in, but are not limited to, carpentry and welding. Often believed that these clamps are called "C" clamps because of their C-shaped frame, or also often called C-clamps or G-clamps
[http://www.technologystudent.com/equip1/cramp1.htm, Information on G-clamps.] because including the screw part, they are shaped like an uppercase letter G. However, in fact, they were originally called a carriage maker's clamp, or Carriage Clamp.
Description
C-clamps or G-clamps are typically made of
steel or
cast iron
Cast iron is a class of iron– carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impu ...
, though smaller clamps may be made of
pot metal. At the top of the "C," is usually a small flat edge. At the bottom is a threaded hole through which a large threaded screw protrudes. One end of this screw contains a flat edge of similar size to the one at the top of the frame, and the other end usually a small metal bar, perpendicular to the screw itself, which is used to gain leverage when tightening the clamp. When the clamp is completely closed, the flat end of the screw is in contact with the flat end on the frame.
[http://www.freepatentsonline.com/5462264.html, ]Patent
A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling disclo ...
for C-clamps. When the clamp is actually used, it is very rare that this occurs. Generally, some other object or objects will be contained between the top and bottom flat edges.
Usage
A G-clamp is used by means of turning the screw through the bottom of the frame until the desired state of pressure or release is reached. In the case that the clamp is being tightened, this is when the objects being secured are satisfactorily secured between the flat end of the screw and the flat end of the frame. If the clamp is being loosened, this is when a sufficient amount of force is released to allow the secured objects to be moved.
Woodworking
While a G-clamp is a useful tool for woodworking, special care should be taken when working with any woods. The flat gripping edges of the frame, generally no larger than half an inch or a centimeter (depending on the size of the clamp) can cause indentations and marring of the surfaces being clamped. This can be avoided by buffering between the clamp and the timber using two pieces of scrap wood. As each piece of scrap wood is directly in contact with the flat edges of the frame and with the items being clamped, this allows the scrap wood to receive the damage from the clamping, while dispersing the clamping force across the piece of scrap wood into the clamped objects. Deep-throated clamps are also available and provide greater reach for smaller jobs.
Stage Lighting
'' see
C-Clamp (stagecraft)
C-clamps are frequently used to hang stage lighting instruments.
See also
*
F-clamp
References
{{commons category, C-clamps (tools)
Woodworking hand tools
Metalworking hand tools