I'm looking for some ideas on how to repeatedly and hold some 20mm OD PVC
round bar in a lathe chuck. I'm turning batches of 20 pieces - they start as
a 25mm length of 20mm OD PVC rod and end up with:

a) an 11mm thru' bore
b) a 17mm x 5mm counterbore.
c) a 17mm OD step on the outside at one end.


Hopefully the cross-section below will make sense of my ramblings:

__________
_____| ____]
|___________]

11mm thru 17mm internal counterbore
bore
___________
|_____ ]____
|__________]

17mm 20mm OD
step



Is there a neat way I can fabricate some sort of jig into which I can
quickly clamp the 25 L x 20 OD PVC pieces so they will be in the same
location? Some sort of simple collet??

I need to achieve 0.5mm accuracy lengthways and 0.2mm on the turned OD and
internal counterbore diameter.
Unfortunately I dont have a milling machine - just the lathe,a CQ6230 lathe
(Chinese copy) with a 3 & 4jaw chucks + faceplates etc.

TIA
Robbo (the novice)