I agree with a fellow reader that swiveling, locking casters are the way to go — I’ve added them to all of my tool carts. The only negative is that, when unlocked by hand, they can spring back and snap against your fingers. It’s not a terrible feeling, but still uncomfortable. Here’s a tool I’ve made that allows me to unlock the casters quickly without having to bend over. I used a block of scrap hardwood, a 4′-long, 1-1/8″-dia. wood dowel and a 5/16″ closed eye hook. The dowel is mounted at a 55° angle in the block. Tipping the tool backward, with the block braced against the floor, unlocks the casters easily.
-Michael R. Long
El Paso, Texas