What are the parts of a bar clamp?

29th February 2020

What are the parts of a bar clamp?


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		A bar clamp’s main parts consist of two jaws, a bar, a handle and a screw.

		Jaws
		The jaws of a bar clamp are two square edges which rest on the bar, facing each other. The head jaw sits at the front of the clamp and is controlled by an adjustable screw. The back jaw slides along the bar and can be locked into place, when in the desired position.

		Bar
		A bar clamp has a long metal bar, usually made from steel or aluminium, which serves as a support for the rest of the clamp parts. The shape of the bar can depend on the type: some models have a flat, rectangular bar, while others have a round bar.

		Handle
		The handle is the part that controls the screw – when the handle is rotated, the screw turns with it. A bar clamp can either have a crank handle or a sliding pin handle (also known as a tommy bar).

		Screw
		A bar clamp has a large threaded screw which, when turned, adjusts the head jaw. The screw commonly takes an ACME form. This is one of the most popular thread forms, as the wider base of the thread makes it stronger than other types.

		Additional parts
		Quick-release lever Some bar clamps may have a quick-release lever. This lever, when pressed, will unlock the back jaw, allowing it to be quickly moved and repositioned. This feature can be useful for fast clamping during long or repetitive applications.

		Pin and holes Models without a quick-release lever will have holes along the bar where a pin can be inserted to keep the back jaw in place. Once the jaw is at the desired position, the pin can be placed into the nearest hole, preventing the jaw from sliding backwards. The other jaw is then adjusted via the handle and screw to complete the closing of the jaws on the workpiece.

		Optional accessories
		Lengthening bar A lengthening bar is designed to be connected to a regular bar clamp, in order to extend the clamping capacity of the tool. When the lengthening bar is attached to the clamp, the jaw opening can be increased by either 900mm or 1200mm, depending on the size of lengthening bar used.