Get a small tap and die set and thread the end of the hair stick
and make the end into a bead that screws on. Tapping a dieing stuff
is easy. No machinery needed. Just a tap and die set.
I've had long hair for years & years and frequently pin my hair up
with a "stick", usually using whatever skinny pointed thing comes
easily to hand..... a pencil, a pen, a chopstick....... I never feel
the need for a "catch".... altho perhaps if I were inserting
something of true artistic value I would wish for one.
One comment I feel compelled to offer here, however: It is extremely
important that the pointed end which I'm attempting to thread & weave
through my hair be very smooth. Any roughness or unevenness in the
surface of the point catches & snags on hairs in very irritating &
semi-painful fashion. The thought of using something with a threaded
end is like chalk on a blackboard to my senses. I strongly suggest
seeking an alternative solution.
Slowly working through my email after being away, so my response is
perhaps a bit dated.