You need level ground, or a block.

They never need oil, nor seals.

I still have a scar from the handle putting a hole on my cheek.

They always looked to me like they were just waiting to have the back side of the base flip up after just one more pump when using the front "hook".

John, one of the jacks cost $6 in 1966.

They always looked pretty dangerous to me.... Hydraulic or screw jack for me. But then again if that's all you had it would be the tool you used.