A molding system having a clamp assembly including a rectangular stationary platen, a rectangular movable platen and platen stroke actuators, the stationary platen being fixedly attached to a frame of the molding system and including a mold support structure configured to support a stationary mold portion of a mold, the movable platen being slidably supported by the frame and including a mold support structure configured to support a movable mold portion of the mold and support structures providing supports for corners of the mold support structure at zones of the movable platen, the platen stroke actuators for linearly stroking the movable platen relative to the stationary platen so as to close and open the mold portions (142, 144) of the mold, each platen stroke actuator having a first end portion connected to the stationary platen or the frame, and a second portion connected to the movable platen, clamps each thereof being mounted to a corner of the stationary platen, and rods each thereof being coupled to one of the clamps of the stationary platen and extending therefrom to a lock mounted to a corner of the movable platen, and being configured for selectively locking and unlocking the rod to the corner of the movable platen, each lock comprising a lock member associated with the rod, and a complementary lock member associated with a sleeve, the sleeve being rotatably coupled a housing fixedly attached to the movable platen and including threads engageable with threads of the sleeve so that the sleeve is rotatable relative to the housing, a lock actuator coupled by way of a belt interface to the sleeve for rotating the same; the lock member including teeth structures having four rows of rod-interrupted teeth extending axially outward from the rod, and four rows of rod grooves extending through the teeth and longitudinally along the rod, said rows of teeth and grooves being positioned 90 degrees from each other, the complementary lock member including teeth structures having four rows of teeth extending axially inward from the sleeve, and four rows of sleeve grooves extending through the teeth and longitudinally along the inner part of the sleeve, said rows of teeth and grooves being positioned 90 degrees from each other, the teeth of the sleeve being rotatably, lockably interactable with the teeth of the rod, such that in an unlocked condition of the lock the teeth of the sleeve line up with the rod grooves and the teeth of the rod line up with the sleeve grooves, and the movable platen is free to translate linearly in a direction aligned along the longitudinal axis of the rod, in a lockable condition of the lock, by rotation of the sleeve, the teeth of the sleeve align with the teeth of the rod along a radially extending axis of the rod extending vertically from a 12 o'clock position to a 6 o'clock position, and along a radially extending axis of the rod extending horizontally from a 3 o'clock position to a 9 o'clock position, and a gap exists between the teeth (238, 248) along the longitudinal axis of the rod so that the teeth (238, 248) do not frictionally interfere with each other, in a locked position of the lock, when the clamp is positioned in the gap closed condition and the rod is caused to move towards the stationary platen, the teeth (238, 248) are caused to abut each other so that, when a clamping force is applied to the rods and the rods are pulled toward the stationary platen, the teeth (238, 248) are placed in locking engagement with each other at zones of the movable platen.