Abstract: A framework joint comprises a square open-ended tube and a connector fitting comprising a preferably cubical hub portion having a tube-receiving projection or post extending from one of two or more faces thereof having a similar projection. Each tube-receiving projection has diametrically opposed portions of maximum spacing adapted frictionally to engage the opposed flat inner surfaces of a square tube and diametrically opposing portions of lesser spacing between said portions of maximum spacing and which provide clearance for the passage of a flexible resilient locking tongue inclining inwardly and axially from the wall of the square tube. The locking tongue preferably has a convex shape to be engageable by the recessed radially outwardly facing surface of a groove formed in the associated tube-receiving projection of the connector fitting.