Kim
Though it would be nice to be able to make any size bushing at will at this time I have absolutely no interest in a metal working lathe.Neither the funds or shop space will permit it.As for as a tenon cutter like that goes.I enjoy working with wood and tools.
I am not a production shop.Pretty much don't think about turning a pen with a crank or a template.
Might as well get into a computer driven set-up and spit pens out all day long and say"This is what I made"(NOT),
Russ.
The purpose for the bushings is so I can get custom parts plated.
I like the design flexibility of working with inexpensive kits.I too when working with slim lines omit the center ring provided with the kit,but I can get rings turned in brass plated.
To save me time I can have the rings plated ahead of time and use them when assembling the kit.The bushings would provide a uniformity.
Take a look at a display of dlim lines with the center ring.They are either modified with a wood,or acrylic center ring or have a wasp waist.
Envision if you will, making 10 modified slimlines each with it's own custom brass center ring,let's say7/16 of an inch dia at the center.
It takes 30 seconds to plate them.I don't want to have to keep track of 10 separate rings and try to figure out which ring goes to which pen.
If you use a busing for the tip when you make your pens why not just use a caliper as you suggested?
Time right? accuracy?