Here’s fresh take on the classic hyperbolic wishing well toy. This one uses a 3/16” / 4-5mm ball bearing in a handheld toy that you spin up with a flick of your wrist. The bearing runs a surprisingly long time, per our usual arrangement.

Pick up a handful of ball bearings at your local bicycle shop. They will no doubt have quite a few used ones on hand. 

The model has a built-in inside brim that doubles as a ball cage at the top of the funnel. With this brim the funnel is usable as printed, but in case younger ones are around a glue-on reinforcing collar is provided to provide more durability. Lastly, a detachable cap is provided to catch the bearing after its adventure down the slide. 

The model is scaled for a Prusa XL and is 12.9” / 328 mm tall. You can scale it down as needed. When scaled down to 4” / 102 mm a 3/16” / 5 mm bearing still has clearance to fall through. 

PLA+ works well.  The collar and cap will print well using 0.25mm Structural, 0.6 nozzle, and all the defaults in PrusaSlicer. 

The funnel is printed in vase mode. Due to the extreme overhang the funnel needs a thinner layer height and wider extrusion width. Use 0.15mm Structural, 0.6 nozzle, Default extrusion width: 0.9, and First layer 0.9.