oldskeet:
piston is like a spool, with the 2 o-rings inside of it
piston OD = 1.075
piston height = 0.403
piston ID = 0.3125 (the inside is threaded, so this measurement is the outside of the threads)
distance from OD edge to ID edge looking down on top of the pressure nut = 0.3795
thickness of the spool = 0.075
o-ring OD = 1.14
o-ring height = 0.20 (there are 2 o-rings one on top of another that are sandwiched inside the pressure nut)
looks like the piston material is some type of hardened carbon steel
i know a pic is best but that is what i have for right now... let me know if you need me to clarify anything