Improved method and apparatus for interlocking hemmed together edges of inner and outer vehicle body panels with an improved interlock joint. The inner panel blank is draw stamped and provided with PLP holes in a stamping press. A plurality of conventional hardware components are then welded to the inner panel. Then interlock holes are formed by a piercing tool moving through the inner panel border from its outboard to its inboard side while the inner panel is held by clamps and PLP pins. The hole piercing punch thus leaves cold worked upset material slightly raised inboard, rather than outboard, around the pierced interlock hole margin. Then the inner panel subassembly is married to the outer panel and transferred to a hemming station and again precisely clamped and positioned by PLP pins, whereupon hemming press gates are operable for hemming the flange lip of the outer panel over the inner panel border. The final hemming steel of each gate carries staking punches that individually strike a precision registered portion of such hemmed lip to deform it into locking engagement with the associated interlock hole. The upset material is thus flattened and accurately worked into embedment into the interior surface of the hemmed flange lip, rather than into the interior surface of the outer panel, thereby avoiding creating read through problems on the outer panel.