Personally I think they are more stable than the crank down jacks. Back in the day -
yes I am that old
- that was your only option. Then someone started attaching the scissor jacks from cars to the camper frame. you could buy 4 from a junk yard for a song and you did not have to have a place to store the stack jacks
. The crank down jacks always seemed to have some wobble.
I remember to use the stack jacks you would lower the front of the camper by about 1/2 bubble then put the rear jacks under then raise the camper past level put the front ones under then lower the tongue jack and you were level and rock solid.