A hinge pin joint for facilitating precise separation of the jaws of a spring clip, comprising: a base cylinder with a threaded bore; supports extending laterally out from said base cylinder; pin supports having means for pivoting; and stabilizing wings extending from the pin supports. In one embodiment, the means for pivoting includes pins that are integral with the pin supports and which extend out laterally from the pin support. An alternate embodiment comprises aligned openings in the pin supports into which pins may be inserted. At least one stopper may be disposed on at least one of the pin supports for supporting the upper shell. The stabilizing wings are configured as plates that are semi-rigidly secured in guide structures within the lower shell.