Methods of forming joints between bars of materials such as mild steel are disclosed. In one method, the bars are arranged to lie in generally parallel planes but with their axes at an angle to one another, and a plastically-deformable tubular stub of round or square cross-section is disposed between the bars with its axis substantially intersecting the axes of the bars, which are then pressed together to deform the stub partially around the two bars. In a second method, a bar is arranged in a T-formation with a hollow member, two opposed regions at the end of the tubular member are deformed inwardly and back along the member axis, and the bar is then pressed into the groove so-formed at the end of the member, to deform the end portion partially around the bar. Heat may be used, in the former case on the stub and in the latter case on the tubular member, so that after completion of the joint the heated stub or tubular member will cool and contract, firmly to grip the or each bar.