About this 3D model

Holds needle roller bearings from Amazon in a "hub" to rest your filament spool on. These are the bearings I used: http://www.amazon.com/gp/product/B006KT1B80/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1 They're large enough I.D. to fit onto a piece standard 1/2" electrical conduit.