These replacement spindles are used on vintage style door knob systems. They feature 3/8 in.–20 custom threading and come in a zinc plated finish. The nominal size of these shafts measure 1/4 in. x 1/4 in. x 3-1/2 in., but their actual size is 17/64 in. x 17/64 in. x 3-1/2 inches. This square spindle fits 9/32 in. and 5/16 in. square openings, but it will not fit into 1/4 in. square drives.