A method of making a closure for a container is accomplished by providing a
unitary mold with a mold cavity therein having vertically extending ribs
and a rotatable and linearly movable threaded core element is received
within the cavity. A formable plastic material is placed within the cavity
and the core element is received within the cavity. Alternatively, the
formable plastic material may be injected into the mold cavity. Upon
contacting the formable plastic material with the core element the plastic
material is forced around the outer surface of the core element and the
inner surface of the cavity forming a closure with an internal thread and
externally extending vertical ribs. The closure and the core element are
backed out of the cavity wherein the core element is moved linearly and
rotatably, but rotation of the closure is prevented. Once the core element
is engaged with the internal threads of the closure only at the
terminating end of the external threads of the core element, the article
is completely removed from the cavity mold. Upon removal from the cavity
mold, the weight of the closure in combination with gravity enables the
closure to fall away from the core element. Alternatively, a concentric
stripping ring or an ejector pin is used to cause the closure to fall away
from the core element.