Required Tools
Set of wrenches
Set of hex wrenches (metric and US)
Scissors
12” ruler
Optional: Two sets of pliers
Start by attaching the four Stepper Motors (E) to the Stepper Motor Brackets (F) using two 8mm Long M3 screws (G) per motor. Be careful not to over tighten.
Add a very small drop of super glue to the edge of the drive shaft on the motor and affix the 3D printed Pulley (H) to the motor with the small hole on the pulley towards the front, circled in green below. Push the Pulley (H) on the Stepper Motor (E) enough so that the end of the shaft lines up with the edge of the pulley.
Repeat this step for all four Stepper Motors (E).
Place the motor assembly on the Bottom Base Plate (A), align the bottom of the Stepper Motor Bracket (F) with the inner holes on the plate like the picture shown below.
In one of the inner holes, insert an 9/16” Long 8-32 Bolt (I) and tighten it into place with an 9/16” Long 8-32 Nylon Lock Nut (J). The screw should be tight enough to hold the Stepper Motor Bracket (F) to the base but loose enough for the assembly to slide down.
Shift the motor assembly outward so the edge of the Stepper Motor Bracket (F) lines up with the edge of the Bottom Base Plate (A). Add another 9/16” Long 8-32 Bolt (I) and 8-32 Nylon Lock Nut (J) to the outside hole, on the opposite row of the first bolt, to fix the Stepper Motor (E) in place. Tighten this bolt down, be careful not to over tighten.
Attach the remaining three motors in the same fashion.
Cut four lengths of Fishing Line (Q) that are at least 15 inches. Using the first 2 inches of the line, tie one to each Pulley (H) using the small hole on the lip of the Pulley (H) (TIP: If you crease the fishing line at the two inch point it will make it easier to tie off). When finished, the assembly should look like this, with a small bundle of Fishing Line (Q) on each Stepper Motor (E).
Next, take the Spring (K) and attach it to the Spring Mount (L) firmly fixing it with hot glue. The best way to get the Spring Mount (L) on is to screw it onto the Spring (K) in the same direction that it coils. Be careful not to pinch yourself. Be sure that the loop on the Spring (K) and a bit of the Spring (K) extend past the base of the Spring Mount (L).
Use the 1” Long 8-32 Socket Head Screw (M) to attach the Spring Mount (L) to the Top Base Plate (N).
On the bottom, tighten four 8-32 Nylon Lock Nuts (J) onto each bolt. Be careful not to over tighten.
The loop on the Spring (K) should stick out slightly past the bottom of the plates.
Add the Large Diameter Disc (O), it will sit on top of the Spring Mount (L) for now.
Next, fix the Small Diameter Disc (P) on to the top of the Spring (K) with some hot glue, make sure the four holes in the disc align with the four holes on the Bottom Base Plate (A). Cut four pieces of Fishing Line (Q) that are about 9 inches long. Crease each Fishing Line (Q) at 2 inches from both ends. Use the crease to hook onto one of the four holes in the Small Diameter Disc (P). The crease allows for all four pieces of Fishing Line (Q) to be tied at the same length. Tie the Large Diameter Disc (O) to the Small Diameter Disc (P) with the bottom crease of the hanging Fishing Line (Q). Try to make both discs sit parallel to the base plate, there should be 4-5 inches between the two discs. The line is represented on the image below by four blue lines. Tie the line to the four holes on the outer edges of the discs.
Next, grab the Bottom Base Plate (A).
Insert the four 3.5” Long ¼-20 Bolts (B) into the four corner holes on the Bottom Base Plate (A).
Add the 2” Long Nylon Spacers (C) and two Split Washers (D) to each bolt.
Fix the top plate assembly to the bottom plate assembly using the 3.5” Long ¼-20 Bolts (B) already on the base and four ¼-20 Nylon Lock Nuts (R). Be careful not to over tighten. The assembly should now look like this:
Finally, run the Fishing Line (Q) through the four holes directly above the Pulleys (H) on the base plates and the four holes on each disc. On the top disc, tie the Fishing Line (Q) using about two inches of line. There should be slack in the Fishing Line (Q) after it is tied.
Wind the Fishing Line (Q) on the motor up onto each Pulley (H), make sure the wire on aligned Stepper Motors (E) sit on the same sides of each Pulley (H). Each motor should mirror the one across from it. The photo below has a blue line that shows what side each wire should be on. The following photo shows the Fishing Line (Q) coiled around the pulley in the correct direction.
As an optional final step, put a spot of hot glue on the Fishing Line (Q) knots that are tied to the discs and trim off the excess Fishing Line (Q).
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