Several months ago I bought a used table saw mounted on a nice cabinet. Only trouble was, the cabinet was on a set of very small and crummy casters. Not only did they (almost) not roll when I wanted to move the saw, but they also *loved* to roll when I was cutting and wanted the thing to sit still!
I designed and fabricated a pair of “toggle action” caster plates to go under both ends of the saw cabinet. They allow me to roll it around smoothly on a set of larger/better casters, then raise the casters off the ground and set the saw on a set of fixed feet. The attached photos illustrate the general design. Obviously, every tool is different, so you’ll have to adapt it to yours.
(1) The “underside” CAD rendering shows how the (brown) caster pate and doubler are mounted to the underside of the tool cabinet, using two hefty door hinges and a (purple) mounting bar. The bar is attched to the underside of the cabinet. Its thickness is determined by the heights of the casters and fixed feet. For my setup, the casters lift the tool off the feet by ~1/2”. The caster mounting plate should be level at this point, or else the casters will not swivel correctly. Note that the caster plate (3/4” plywood) is doubled, except where the casters are mounted. I added this feature to the design after I noticed that a single piece of 3/4” ply is a bit too flexible. The fixed feet are cut from 2x4s and include rubber cups. PS - the horizontal “discs” on the casters are just to show where clearance is needed when they swivel.
(2) The first photo shows the toggle action mechanism set to lift the tool onto the casters. The operating rod is a piece of 1/2” steel from Home Depot. The wood is drilled through, the end of the rod threded, and a short bolt used to hold the rod against the inside of the hinge. Note: If the tool is heavier on one side than the other, the lifting mechanism can be located off center to compensate. Also note that the rod should be long enough to provide enough leverage to easily raise and lower the tool. The front-to-back width of the toggle bars comes into play here. If they’re too wide, you lose leverage and have to work harder to raise the tool. They don’t have to be very wide, as the load is straignt up-and-down when they’re together ... but they shoudn’t be too skinny, either. You don’t want the toggle to kink unexpectedly when you hit a rough spot in the floor!
(3) The second photo shows how the tool is lowered onto the feet. The casters are still resting on the ground, but bear no weight. Note the steel plate reinforcement at the outer end of the rod, and the (cut off and epoxied-in-place) bolt at the upper hinge joint.
(4) The last photo shows how the lower pivot joint is made. It has to flex in two directions. I epoxied an eyebolt into the bar, then epoxied threaded rod into a hole drilled into the edge of the caster plate and the “abbreviated” doubler. A stack of washers gives a loosy-goosy joint between the eyebolt and threaded rod.
Obviously, this mechanism could be built out of steel or other materials, and adapted to any number of tools or tables. However, weight will eventually become a factor!
Best wishes!
