Tap/die measurements for over/under shotgun rollerball?

[putnamm]

I have a few extra of these pen kits and want to try making a kitless using the components. Does anyone know specifically what tap and die set I would need?

This is the kit in question: https://www.woodturnerscatalog.com/p/2/6090/PSI-Over-and-Under-Rollerball-Shotgun-Pen-Kit

 

[magpens]

Would have to measure the thread diameter with a caliper or micrometer,
and have to measure the thread pitch (spacing) with a thread gauge.

Then you have to figure out if it is a triple start, double start, or whatever, thread.

I don't have one of those kits so can't give you the numbers.