The earliest mitre clamps are a simple spring in a C-shape with sharpened points that are sprung onto the outside corner of the mitre joint.[citation needed]
In a later design, right angled plates are higher than the screws and the holder.[citation needed] The screws go under the frame (work-piece) to be held, and the bit clamps down on the lower-edge of the frame.[citation needed]
Recent designs are more complicated; a rigid body holds one fixed and one moveable
jaw activated by a
cam.[citation needed] An example of newer clamps is Jim Chestnut's Clam Clamp.[8]
References
^Magazines, Hearst (August 1931).
Popular Mechanics. Hearst Magazines. p. 347.