What are the parts of an F-clamp?

28th February 2020

What are the parts of an F-clamp?


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		The main parts of an F-clamp consist of a bar, two jaws, a screw and a handle.

		Bar
		An F-clamp’s bar can also be called the sliding arm. The bar of an F-clamp is a long, straight piece of metal which is strong enough to withstand the pressure of clamping heavy workpieces.

		Along the top of the bar are serrated edges, which are designed to give extra grip to lock the moveable jaw in place during clamping.

		The bar is made from forged steel and is tempered, a heat treating process which increases the toughness of the metal. Although tempering can reduce the hardness of the forged steel very slightly, it actually improves the overall quality of the metal, as it results in steel that is much less brittle.

		The bar can also be galvanised, which adds a protective layer of zinc over the steel and increases its resistance to rust.

		Jaws
		The jaws are responsible for gripping on to the workpiece and holding it securely in place.


		The jaws are thin metal plates, placed parallel to each other. One jaw is situated at the end of the bar and is fixed in place. The other jaw is placed at the end of a sliding arm which can move along the metal bar, adjusting to the desired position.

		The clamping plates of the jaws are covered by plastic pads, in order to protect the clamped material from being damaged.

		Screw
		An F-clamp has a threaded screw which controls the rounded plate of the moveable jaw. When the screw is tightened it brings the moveable jaw closer to the fixed, closing the two together. In contrast, when the screw is loosened it pulls the moveable jaw away, increasing the gap between the jaw plates.

		ACME is the thread ‘form’ used in an F-clamp, which refers to the shape of the helical ridge around the screw.

		Handle
		The handle is connected to the clamp’s screw. An F-clamp generally has a large handle which is designed to provide a comfortable grip when tightening the screw.

		The handle is also designed to be used one-handed if the user has one hand full.

		Although less common, some models of F-clamp have a sliding pin handle, known as a tommy bar.

		Additional features
		Spring lock Some F-clamps have a spring lock mechanism which allows the moveable jaw to quickly slide along the serrated frame when the trigger is pressed. Once in the correct position, the jaw is locked into place when the trigger is released.

		Tilting jaw Some models are designed with a tilting plate on the moveable jaw, to allow the clamp to grip on to tapered or angled workpieces.