Abstract: In furniture construction a joint is formed between an upright post and the dovetail shaped end of a rail member by the clamping action of a pair of disc-shaped cap members having coaxially slanted interior peripheral portions that mate with the notches of the dovetail rail end. The cap members are mounted on an axially extending rod, and screw threads allow one of the cap members to be rotated into clamping position. A sleeve on the rod and extending between the cap members has vertical ribs for interfitting with vertical grooves in the ends of rail members to prevent overturning of the rail members. In certain embodiments, provision is made for preloading of joint elements. Various arrangements of joined elements make a wide range of furniture assemblies possible.