Originally Posted by beagle22b07
I recently read a post here that stated that the jacks were in their most stable position when extended over 12". This changed my thoughts on using blocking as I used them so I wouldn't have to crank as far. Since then I've got a bit for my cordless drill and use blocking sparingly.
This depends on the design of the jack/stabilizer.
Typical 'scissor' jacks are the most stable when the two upper arms and the two lower arms are extended far enough to form a square.
Stabilizer jacks (electric and manual) are the most stable when the cross arm (sometimes painted yellow/sometimes black) extends to the point where it forms a right angle with the ground contact leg.
Front landing gear/jacks on 5th wheels are most stable retracted, using the inner leg as the needed extension.
Sturdy blocking to get what is described for any of the above, will not affect stability.