F-Clamps

An F-clamp -- named for the rough F shape the fixed foot and sliding jaw trace along the bar -- is the default bar clamp: a foot fixed near one end, a second jaw that slides freely along the bar to get close to the work, then tightens the last distance with a screw handle. That combination of fast coarse positioning and fine screw pressure makes it the general-purpose workhorse for panel glue-ups, case assembly, and anywhere a clamp needs real reach along one axis.

Pipe clamps use the same basic mechanism on plumbing pipe instead of a dedicated bar; parallel clamps refine the same idea further with a rectangular beam and self-squaring jaws.