Frame corner structure

A method of manufacturing a corner structure for window frames and the like comprising:

• providing a pair of metal frame members each having a longitudinally extending channel extending from a mitred end, each channel being defined by opposed sides,
• providing a bracket having a pair of angularly disposed legs slidably receivable in the channels of said frame members, each leg having a surface opposed to a surface on an adjacent leg, and each opposed surface having a pair of longitudinally spaced depressions therein, the depression in each leg nearest the other leg having a depth less than the depth of the other depression in the leg by at least the thickness of a side of the channel of a frame member,
• inserting the bracket legs into the channels of the frame members to cause the mitred ends of the frame members to abut,
• forcing a die, having four striking elements, such that the striking elements are of a dimension that permits two of the striking elements to make contact and traverse the walls of the opposed sides of the corner structure, before the other two striking elements make contact with said opposed sides, against the frame member channels to strike out tongues from each frame member channel into the deeper depressions in the bracket arms and immediately thereafter to strike out tongues from each frame member into the depressions of less depth in the bracket arms to urge the mitred ends of the frame members together, each tongue extending in a direction away from the respective mitred end.