Review on 🔀 KangTeer Stainless Power Transmission Products: Universal Rotation Transfer Efficiency by Jared Winebrenner

For the price, they get the job done. Note that I used 4 casters to support the 2lb router, so I can't speak to performance on the heavier end of the specs. I installed the casters through a 1-1/4" hole drilled in a 3/4" board. The ball sticks out of the ground just enough to roll (perhaps a 1/16 inch gap). 1 of 4 rollers was a bit uneven, which I fixed by loosening the ball: 1) Place the roller on the garage concrete floor (ball up) 2) Hold the wooden strip on top of the ball 3) Tap Gently hit the ball down with a racquet (using wood to protect the ball) until you loosen the ball to the point where it rolls more freely. Place the roller (gently but not firmly) in a vise (ball down with tabs over the vise) and tap the other way. I can't promise this will work for you, but it worked for me.