This is a print ready chain hoist capable of 30lbs or more (30lbs is all I had on hand to test with). 8x16x4 Ball Bearings, #10 Ball Chain and 3 different M3 screws are required to make this function.Video: http://vimeo.com/42907056The system has a 3 stage reduction. They are as follows: Drive 2 to Drive 1: 27:9 or 3:1 Final Drive to Drive 3: 27:9 or 3:1 Doubler Pulley: 2:1 For a total reduction of 18:1Purpose of this thing: I was bored and had a few bearings sitting around so I decided to see how much I could lift using plastic.Start by printing a few copies of Drive 3. You will need to modify your print profiles to make sure that the inner area of each tooth is filled in. They need to be solid to transmit the torque required.Once you have a gear that is solid, continue printing the rest of the components.Press the bearings into the recesses in the two sideplates, the Final Drive and the pulley. Add Drive 1, Drive 3 and Final Drive to Sideplate Left.Add Drive 2 to the other side of Sideplate Left. It usually helps to have Drive 1 pushed out when adding the Drive 2 gears.Press ends of the load ball chain into Ball Retainer and MirrorBall Retainer. Secure these to the correct location on Sideplate Right using M3x12 Flathead.Add the Hook to Sideplate Left and assemble with Sideplate Right. Use 3 M3x16s to secure it together. Note: at this time, you will need to wrap the load ball chain around Final Drive otherwise you won't have a load on the drives. It takes some trial and error to make it wind the correct way. The load portion of the chain should be centered in the middle and not off to one side.To test the mesh and make sure everything is wound correctly, lightly add Input Drive to Drive 1 and turn clockwise. Your load should go up at this point. If it does not, it is not wound correctly. Correct and check again.Add the two Ratchets to the Sideplate Right. Point them towards the center to make assembly with the Input Drive easier.Add the Ratchet Plate, the Spring and the Spring ring to the Input Drive. Press this assembly on to Drive 1 until the Ratchets touch the back of the Ratchet Plate. Using a screwdriver or other impliment, turn the ratchets so they engage the ratchet plate correctly while applying pressure to the Input Drive. Once it is completely seated, add the M3x12 to hold it all together.Add the drive chain and then the two top sectionsFinish by assembling the doubler in place on the load chain.You now have a fully functional chain hoist.Cheap #10 Ball Chain http://rolleasepartsexpress.com/rolleasenickelsteelcontiniouschainloop2ft24inchdrop48inchtotallength-1-1.aspx The continuous length is necessary for the input chain only.