Originally Posted by Bill

dalberdash -

You are aware of the quick-and-dirty solution to this, right? Get a cheap battery-powered reversible electric drill. Also get a reasonably large allen wrench - 1/4" is a nice size. Chuck the long end of the allen wrench in the drill. Slip the small end of the allen wrench through the crank-hole in the jack. Pull the trigger, and ZIP! It's done.

This is real simple. Others will suggest slightly more complex versions of the same solution - also good. By the way, a lightweight drill will lower the jack to the ground, and set it firmly there, but that's all. If you actually want to raise the trailer using the jacks, you'll need a heavy-duty drill.

Bill