How to respool garage door cables??

[cbassett]

I'm not sure how it happened, but the cables that run down either end of the garage door popped off their spools.

It happened in the morning before work... There I was, running late and with a garage door that wouldn't close the last 2 feet (the cables were pinching themselves on the rod that big spring and the spools rides on). So I unhooked the cables from the door and set the door down unsprung. Good GAWD those doors are heavy!

So now I'm faced with respooling the cables in proper tension to counterweight the door through it's range of motion again. Is there some trick or tool to aid in doing this?? I started doing this by hand but couldn't get close to full spool.... and I had the other spool to deal with too!