Parts of a Clamp – C-Clamp and Bar Clamp Labeled

All 9 parts on the diagram

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C-clamp 5

Screw Turning it closes the clamp on the work or lets it go.
Handle It is used to turn the screw. On a C-clamp it is usually a small bar set across the screw.
Frame One flat clamping face is on the frame. The screw is threaded through its other arm.
Swivel pad It turns freely on the end of the screw. The screw can then turn without turning the work.
Throat The depth of the opening. It runs from the back of the frame to the line of the screw.

Bar clamp 4

Bar A flat steel bar. The longer it is, the wider the work the clamp can take.
Fixed jaw It is fixed to the end of the bar. It takes one side of the work.
Sliding jaw It slides along the bar to the size of the work. The screw is in its end.
Clutch discs They let the sliding jaw move freely along the bar. They grip the bar when the clamp is tightened.

How this list was compiled: Every name checked on 2026-09-30 and kept only where at least two of these use it. (1) Wikipedia, C-clamp, F-clamp, Pipe clamp and Clamp (tool), https://en.wikipedia.org/wiki/C-clamp and https://en.wikipedia.org/wiki/F-clamp : the C-shaped frame with a flat surface at one end, the screw through a threaded hole at the other, the pad that swivels freely on the screw, the handle, a small bar across the screw; the bar clamp's bar, jaws, screw and throat; clutches that let the moving head of a pipe clamp slide and then hold. (2) US Navy, Tools and Their Uses (1971), full text at https://archive.org/details/ERIC_ED132362 : a C-clamp is a steel frame threaded to receive an operating screw with a swivel head. (3) US Army, TM 9-243, full text at https://archive.org/details/use-and-care-of-hand-tools-and-measuring-tools-1983 : C-clamps, their threads and swivel. (4) A clamp maker's catalog, https://archive.org/details/JorgensenAndPonyClampsCatalogNo17 : C-clamp frame, swivel, screw, handle and depth of throat; steel bar clamps with a fixed head and a sliding head, and the multiple-disc clutch with its clutch discs. (5) A second clamp maker's catalog and parts list, https://archive.org/details/taylor-clamps-catalog-18 : steel bar, stationary head, sliding jaw, screw, disc clutches. (6) Two more makers' catalogs, https://archive.org/details/hartford-clamp-co-catalog-no-60 and https://archive.org/details/WiltonClampingToolsCatalogNo131 : bar, screw, handle; C-clamp frames and throat. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's tool, nothing traced. Licence: own work

How it works

Two clamps on one drawing. The C-clamp on the left is a frame with a screw through it. The bar clamp on the right, also called an F-clamp, has two jaws on a long bar.

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The C-clamp

The frame is shaped like the letter C. One clamping face is on the frame. The screw is threaded through the other arm, and the swivel pad on its end is the second face. Turn the handle and the pad closes on the work; because the pad swivels, the work does not turn with the screw. The throat is the depth of the opening.

The bar clamp

The fixed jaw is at one end of the bar. The sliding jaw moves along the bar to the size of the work, and its clutch discs grip the bar when the screw is tightened.

A pipe clamp is built the same way as a bar clamp, with a length of pipe in place of the flat bar.

Questions and answers

What are the parts of a C-clamp?

A C-shaped frame, a screw threaded through one arm of the frame, a swivel pad on the end of the screw and a handle to turn it. The open depth of the C is called the throat.

What are the parts of a bar clamp?

A flat steel bar, a fixed jaw at one end, and a sliding jaw that carries the screw and its handle. Clutch discs under the sliding jaw let it slide along the bar and then hold it in place.

Why does the pad on a C-clamp swivel?

So the screw can be turned without turning the thing being held. The pad stays still against the work while the screw turns inside it.

Is an F-clamp the same as a bar clamp?

Yes. F-clamp, bar clamp and speed clamp are names for the same tool. The name F-clamp comes from its shape: two jaws standing out from a long bar.