Thanks,
The actual machining was contracted out as I didn't have a suitable lathe to turn the 127mm/5inch raw diameter, or the 60mm bore etc etc.
I've pressure tested the pressure chamber with the hydraulic calibrator shown the gasket finally gave away at 3,370metres probably due to the grade 12.9 bolts lengthening. LOL and yes when the gasket blew it sounded like a gun shot.
I use plain tap water as it's a safe hydraulic media certainly wouldn't want to use hydraulic oil.
The pressure calibrator and gauge were bought from the US firm below at the time the US currency was close to $2 a £1 so some cracking deals could be had.
I generally test with kg/cm2 pressure units which is easy for depth conversion simply times x10 and you have metres in depth.
http://www.ptsinstruments.com/Some serious pressure there and nice work by the way.
Have you pressure tested the pressure tester?
Just wondering what you pump in, water or oil.
Usually fill cylinders with water and pump oil in from a modded 10000psi grease gun with clock or enerpack.
That looks a tasty guage.
Tell us more.