[Jim Dawson]

Thanks for your additional comments, Ger21, and JimDawson!

My pleasure

You've converted me. I'll be running the tubing through the cable chain to a reservoir that sits outside of the machine frame. Right now I'm thinking about using 10mm OD, 6.5mm ID PU tubing, and 10mm push in fittings.

I knew we would bring you around :cheers:

You guys are right about the pressure drop.

32mm diameter is approx 1.25 square inches

Let's say I run the Z at 400 IPM max

400 IPM x 1.25 in^2 x 2 (2 cylinders) = 1000 in^3/min = 0.58 cubic feet per min

I looked at a few online calculators, and over a 15 foot length, the pressure drop is negligible (way less than one PSI). Someone please correct me if I made a mistake there. Also, I could use 8mm OD, 5mm ID, but the price is about the same, so I figure 10mm OD will be fine.

Your math is correct. The pressure drop will be negligible.

The fittings I'm looking at on aliexpress are "G" fittings which I assume is the same as BSP? If I use an old air compressor tank, I will need to find a 3/8 BSP (female) to 1/4 NPT (male) adaptor, but I assume those are available on EBay.

G fittings are a straight Whitworth thread with an O-ring for a seal
R fittings I think have a tapered BSP thread
F fittings have a US style NPT thread.

Actually what I plan on doing at this point is to use an old fire extinguisher as the air reservoir.

Just make sure the tank is not rusted out or something bad.