
Turn a chunk of round scrap and make two big buckets of swarf...

Turned another piece to be a cosy fit and cut a groove in it for an o-ring.

Put the two pieces together and fill the gap with oil.

Put the ensemble under the end of this shipping container.

There is a 100Bar pressure gauge on the end of that copper pipe!
The piston is 114mm in diameter and according to my calculation and indication of 100Bar would be 10 tonnes, here we can see a much lower reading showing this end of the container weights about 1.4 tonnes, I will need to do the other end too and add them together but I am guessing this fairly empty container weighs 3 tonnes.
This is useful information as it shows I can put 3 tonnes of my treasures in there and still get it shipped to our new house at the lowest freight rate!