cheap and make great bearings for ...anything. I use them for phono turntable bearings. Most remarkable test. I carefully secured a 2 mm ball bearing on a hard steel vice. I then took a common carpenter's steel hammer and hit the bearing as hard as I could. Nothing. Under a 100x microscope power, there were absolutely NO nicks, scratches or visible damage. I lack test gear to detect internal structural change. The shiny surface was not scored in any detectable way. Dear lord, silicon nitride (ceramic) bearings are harder than 660 steel. I first used this material 25 years ago.
