Custom Parametric Bearing with Steel Balls

prusaprinters

WHAT IS NEEDEDThese bearing are almost completely parametric and use steel balls to work. You can easily find these steel balls for bearing or for cleaning purposes and they are perfect for the tolerances of the plastic rings.In the .3mf files you can find some bearing dimensions but you can ask for specific dimensions if you need them.At the moment all the bearings I published are using 3mm steel balls so their dimensions are on the small side (15mm to 150mm of external diameter I would say) because larger bearings need larger balls and with these 3mm ones they do not spin well.Don't know why but the bearing that works the best is the 608. PRINTINGChoose the size you want and print it. It is better to not print it in place as the file is loaded but at least arrange the 3 parts separately. Since every imperfection could ruin its performance, it's better to minimize them. Place it like this (or every part alone) and check for yellow and continuous internal perimeters.Use PETG, 0.4mm external perimeters width, 4 perimeters, 100% infill. Print the core at 0.1mm layers height; external rings should be good with 0.2mm layers height. ASSEMBLY INSTRUCTIONSIt will be not an easy task assembling these but try following these instructions.Take all the printed parts, the correct number of steel balls (6 for the 608 bearing) and a tweezer: use it to move the steel ballsPlace the steel ball inside the outer ringPlace inside it the inner ring: it has to touch the tableWhile pushing the inner ring towards the centre of the outer ring move the steel balls in order to not have any of them above othersNow you need to lift one ball at a time in order to slide them between the two rings, towards the tighter space between the ringsPay extreme attention now: do not move the rings or the steel balls could move and come back to their previous place. Move the steel balls with the tweezer in order to set them about at the same distanceAgain with extreme care, move the rings over the core, the retaining bracket for the steel balls, and place the rings over itIf not aligned yet, move the steel balls in their cavities and then apply a discrete force on the rings: they should snap in place. You can apply the force starting from one side, tooThe bearing is completeApply some grease or lubricant on the steel balls if you want a smoother spinning  These bearings are not made for high speed or high loads but they should do the job for easy tasks. Anyway, I tested the smaller ones at high speed and they kept up without any problems. Feel free to leave me a comment for suggestions, problems or requests.