This mechanical design model showcases a large variety of parts essential to mechanical gearbox design. Not only does this model look great assembled on a desk or shelf, assembling and disassembling it can teach you a lot about the use of bearings, gears, seals, and other elements of mechanical design.

I assembled by model using two 40mm x 52mm x 7mm ball bearings and three M6x10 screws, but if you don't have these on hand, don't worry! Included in my print profiles and raw model files are demonstration bearings matching these dimensions. While your shaft won't spin quite as smoothly as with real bearings, they will certainly suffice to assemble the model and allow you to play with it. The screws aren't necessarily essential either. They are easy to find in any hardware store, though, and definitely contribute to the sturdy look and feel of the model.

As you can see, I made the shaft printable in two parts. These can be glued together permanently after printing.

Happy assembling!