It appears that these doors were already make shift to me. I originally thought the nylon was threaded but it just appears that the bolt eventually pushed through the door pin cap.
Paul from SWISCO responded:
December 12, 2017
Thank you for posting. I believe you may be able to use our 21-108 bifold door pin cap that would fit into our 21-014 bifold door pin, not a threaded pin. Take a look at both products and let us know what you think.