The multiple part ball bearing assembly.
If you like our design and would like to build it so that it is as strong as Samson himself, then please order some 3Dynamic Systems Carbon Fiber Filament $50 for 1kg of 1.75mm diameter filament.
To order your free sample of 3DS Carbon Fiber filament then please visit: http://www.bioprintingsystems.com/carbon-fibre-3d-printer-filament.html