A rock tumbler that requires 8 bearings (4 per unit) so you dont have friction,the tubes you need you can get in any hardware store,designed to fit either 40mm or 50mm tube/pipe,pvc tube does the job for me, all you need is the gearing,later on i will ad some gears to it,the bearings you get on ebay ABEC-5 608-ZZ,the center is 8mm,i used alu rods (dont need the pins if you go for rods). basically,just downloading the face file,canister and lids,the rest you can design as you need (the adaptor for the pipe you wil use,its a minute job,will upload later also) use rubber sealing for the lid spacing,to close the canister use a threated rod--IF one of the parts loads to small on plater,multiply it by 10 (scale) UPDATED. New housing allows you to use a motor holder housing,desgined for the ones from arduino (ebay,arduino motor) with diam of 26. the housing can be connected with 2 8mm rods,the lenght is up to you to fit the gears. New feauters. removed gear system,replaced with pulleys,so you can adjust it to your need of speed or torque (in any matter,speed control) with not much work,just change motor pulley and done