configured to interact with the side plates of the female die the male die is moved toward anvil surface 14 with sufficient force to cut the metal sheets at the edges of side plates 22 and 24 this cut material between side plates 22 and 24 is engaged by further interaction of the male die and the female die so that the material is spread by material flow to form a strong joint between the two sheets as the material flow occurs side plates 22 and 24 are forced apart to facilitate the material flow when the joint is complete and removed from the female die it is important that side plates 22 and 24 be urged back into contact with anvil surface 14 the die shown in figures and 1 and 2 is readily assembled by positioning the side plates against the sides of anvil 14 with the spring members engaged the second ends 52 of the spring members are then directed into receptacles 38 which are shown as drilled holes in base 18 the side plates are then pushed downwardly to move the springs into receptacles 38 in base 18 receptacles 38 are oriented to result in the thus positioned spring members maintaining plates 22 and 24 in contact with the sides of anvil 14 side plates 22 and 24 may be made of any suitably hard material which will be effective to shear the metal sheets for instance any suitable oil hardened or air hardened die steel may.