Have been using the bottle jack in the conventional orientation for "Pressing" matters. (No pun intended), but always wanted to have it like a commercial press.
Been reading a lot about converting a bottle jack to work upside down, but just all seemed like too much work and messy..
So took from every post what made sense and combines it.
Best option too create a reservoir tank filling point was to use the original jack filling hole. First problem my Chinese jack had no tread, just a rubber grommet.
So i found a M8 fine thread nut and welded it over the existing hole to allow a 8mm pipe connector to be screwed in. Took my time welding as all the oil was still inside the jack. I extended the jack fully to ensure as little as possible oil in the outer reservoir of the jack.
Then machined an 14mm bolt to become the connector in my jam jar oil reservoir.
Keeping the Jack on its side I primed it untill there was no more air in its system.
the jack could then bu turned upside down and it works. No stripping, no mess and the jack can be converted back to normal easily.
Now finally added the springs to pull back the ram. Job done, now for a coat of paint and some M12 Hi Tensile bolts as adjuster pins.