Patrick writes: “These are my favorite addition to my contractor’s table saw. Instead of installing a mobile base, these retracting casters attach to the splayed legs of the table saw. When retracted, they allow the saw to sit securely on the floor (as God intended), then they easily pop down when I need to move the saw.”
I’ve used a version of this that’s mounted to an adjustable square base, but this looks like it’d be more versatile.
The one pictured comes from woodcraft.com — a set of four runs $40.
Retracting Casters [Woodcraft.com]