A cord winder that can do up to 8 cords at once.

Required Materials:
1/4in hex/allen key

608 bearings (8mm x 22mm x 7mm) (10 bearings for 4 cords, 18 bearings for 8 cords)

Screw in hooks (I used hooks out of this assortment I had sitting around: https://www.amazon.com/Ceiling-Coated-Screw-Kitchen-Hanging/dp/B08ZSDW8S1 but anything that screws in and holds your cords will work)

8x2.5mm tapered flat head screws (less than 25mm long or they will poke out the back)

Assembly instructions:

Set the bearings for the sun gear and the planetary gears in the frame

Insert the planetary gears into the bearings

Insert the sun gear into the center of the planetary gears

Place bearings on the planetary gears

Please top bearing on the sun gear

Insert hex key through the sun gear bearings and sun gear to keep sun gear bearings aligned

Place lid over the assembly and carefully align the openings with the tops of the planetary gears

The lid is designed to flex slightly as you tighten the screws, this it to ensure that the gears are held securely centered in the mechanism

As you tighten the screws, make sure that you wiggle the planetary gears to ensure that the top bearings properly go into their places in the lid

Place the locking tab on the short end of the hex key

Operation instructions: 

Wind your string between the hooks on the winder and your static hooks

Ensure that all strings have roughly equal tension

Hold the outside of the winder and pull it towards the drill so that the hex key rotates freely in the assembly

Run the drill until the desired tightness is reached

Allow the locking tab on the hex key to slide into the slot in the lid to prevent the cords from unwinding

Run the drill (do not change the drill direction) until the rope/cord no longer tries to twist up when you release the tension

Tie string tightly around the ends of your rope/cord to keep it from unwinding and pull/cut it off of the hooks

I recommend either gluing the ends of your ropes or knotting the ends to permanently prevent unwinding.

Split into objects, print in PLA with supports for the gears.