In this marble run, it's the track that moves! My goal with this project was to pack many paths into a small space while using many small bearings so there's always something moving. Also, the small scale means that there's always something in motion.

• The entire track is lit by an LED running up the central screw which is used to raise the balls up to the top of the track.
• You can easily use any light colored filament to customize the color of the light that is emanating from your track.

With this many bearings moving, it can get a little noisy, but potentiometer allows you to slow the rotation of the track and therefore the frequency with which bearings are running through the tracks. See (and hear) it in action in this video.

Please note the printing tips at the bottom of this listing and I would recommend reviewing these and the instructions before beginning the project.

Non-Printed Parts

Please check the parts list in your market against the US store to confirm that all parts are being added. I've heard from some users in Canada that the steel balls are not available in that store.

Printed parts

1. Electronics base 
2. Motor cover 
3. Motor gear
4. Screw 
5. Screw cap
6. Rotating base
7. Decorative base
8. Potentiometer cap 
9. Power switch cap
10. Columns (4)
11. Column base
12. Swirls (2)
13. Chutes (2)
14. Middle support ring
15. Director 
16. Zigzag (2)
17. Drop chute (2)
18. Lid
19. Decorative top

Assembly Instructions

Remove all supports (including the four small supports from the bottom of the base, which is an area where the screws to be countersunk). Check all areas where balls will travel to ensure that there are no bumps or strings that could impede the balls.   Even though small, the 'hairs' in this photo were blocking some balls from flowing freely until cleaned up.
Attach an SH1.0 wire to the DC motor and place it into the electronics base. This will be a tight fit. Attach the motor cover with two 2x8 screws and press the motor gear into place.
Attach a SH1.0 wire to the switch and attach to the electronics base where shown using two 2x8 screws.
Attach a SH1.0 wire to the potentiometer and attach to the electronics base where shown using two 2x8 screws.    Important: The dial in the potentiometer is not aligned to the screw holes. Please make sure that it is rotated as shown with the SH 1.0 port pointing up.
Attach an SH1.0 wire to the COB LED. Feed the end of the LED through the hole in the bottom of the electronics base and up through the top - pull it as far as it can go without putting too much pressure on the circuit board.
Attach the wires for the switch, potentiometer and LED to the power distribution board as shown along with jumpers. You may want to use tape or the channels in the base to ensure that the wires are kept away from the moving parts. Power Switch Potentiometer Jumper Power In Motor LED
Attach the power distribution board to the electronics base with two 2x8 screws - the power cord will be added later. Test the electronics before continuing. The switch should control power to all components and the potentiometer should control the speed of the motor.   Pass the wires from the USB power cord through the back of the decorative base leaving the USB connector on the outside.    Connect the power to the power distribution board
Press the bearing into the rotating base. Do this on a flat surface so that you can apply good pressure and ensure that the bearing is firmly and fully in place while being perfectly level.
Flip the rotating base and press it onto the electronics base - make sure it is in alignment with the motor gear.  Use firm and even pressure towards the center of the base. If possible, apply most of the pressure to the bearing itself so that the base isn't damaged or warped. As with the previous steps, it's important that these pieces are fully and levelly mounted.
For A1 Mini only: because the central screw is too tall for the A1 mini, a separate profile is included with the part split into two pieces. This can be pressed together with glue and will be a very tight fit. Be sure to align them perfectly before pressing to fit.   Additional sanding or trimming may be needed to ensure that the parts travel smoothly without catching on the support columns.
Feed the LED in through the base of the screw. You will have to move the screw closer to the base as you go. Once the end of the LED is through the top of the screw, press the screw firmly into the base. This should be a tight fit and it's important that it is snug.   Loop the end of the LED over the bar and place the cap on top.   Important note: if you have any issues with the track ‘sticking’ when rotating, it can be helpful to slightly sand the edges of the screw or the interior of the columns. I didn't need to take this step but some users have needed to do so.
Lower the electronics base into the decorative base.    Plug in the USB power and test to ensure that The light, motor, potentiometer and switch are all functioning as expected.   Tilt the bases to the side, align the screw holes and use four 2x8 screws to firmly attach the parts.    There's a small cube within the decorative base that can be used to align the electronics base.
Press the potentiometer cap through the decorative base and onto the potentiometer.    Press the power switch cap through the decorative base and onto the power switch using the same process.
Press the four columns and four 2x33 brass dowels into the column base.   Press the swirls and shoots onto the brass dowels. Note the alignment of each so that the top is facing up. Depending on your printer and filament, these could be loose or a tight fit - either will work but the swirls are particularly delicate.    Place four total 2x13 brass dowels into the tops of the swirls and chutes.
Slide the middle support ring down at over the columns to rest on the pegs in the middle of the columns. Make sure that the support ring is rotated so that the funnels are directly over the swirls. The brass dowels on top of the swirls will fit into slots on the bottom of the support ring.
Slide the column assembly down over the screw so that it sits on the rotating base.
Attach the zigzags and drop chutes to the bottom of the director using two 2x8 screws each.
Slide the director down over the columns. Align it so that the drop chutes are directly over the funnels in the middle support ring. You will need to slightly bend the zigzags so that they can clear the middle support ring.
The end of these zigzags have a small hole where you can feed in the brass doll from the tops of the Chutes. The shoots can rotate back against the zigzag so that their base is angled along the curve of the column base. Depending on how loose these pieces are, a small drop of glue may be needed to hold the chute to the end of this zigzag. I would recommend waiting to see if this is needed before adding glue because it would make disassembly or changes more difficult.
Lower the acrylic tube over the components and onto the rotating base. This will be a snug fit so be careful not to damage any pieces of the track on the way. The acrylic tube should sit snugly but levelly on the base.   Place the lid on the top of the acrylic tube and align it to the columns so that it sits flush.    Add the decorative top above the lid. Note that this will only rest lightly on top of the protruding central screw cap - this is intentional so that the decorative top does not rotate with the acrylic portion.

Printing & post-processing tips 

• The two print profiles are identical except for the central screw which is split in half for printing on A1 Mini.
  • Although I have printed this tall central screw on P1S successfully, some users have reported issues due to the height. If you are having issues printing this part, I recommend using the separate A1 Mini profile which splits this screw into 2 parts that can be glued together. 
• Balls getting stuck?
  • If balls are getting stuck in the zig-zag portions of the track, an alternate of this model is available on a separate plate.
  • These alternate zig-zags are slightly wider and have one less curve so that their angle can be steeper.
• I have tested all parts on both P1S and A1 Mini and was able to print them successfully. You may need to slow down your print speed on A1 models for taller parts.
• Because many of the parts will be visible from all angles, I would recommend printing on a smooth plate. 
• My test prints were entirely in PLA, but moderate strength filament with limited stringing should work.
• Several of the parts can be delicate, so please handle them gently. 
• When choosing a filament for the screw, choose something that is a light color with good light transmission.

Updates

• Dec. 31st: updated the potentiometer knob and power switch to use the same color shown in the photographs for this post.
• Jan. 1st: Corrected support settings for the “mid-base” part.
• Jan. 4th: updated the ‘backstops’ on the zig-zags to be longer so that they are easier to glue.
• Jan. 7th: 
  • Added a tab to the decorative and electronics base to ease alignment. 
  • Updated the assembly instructions for the potentiometer to clarify the orientation. This doesn't represent a change to the geometry.
  • Reduced the length of the central columns by 1mm while increasing the negative space in the lid by 1mm to account for small variations in the height of the acrylic tubes in the manufacturing process.
  • Slightly reduced the size of the screw holes in the bases for a tighter fit.
• Jan 15th:
  • Updated & corrected the support settings on the decorative base for the bottom screw holes.
  • Updated the wide zig-zag option to have a steeper angle as an optional solution when balls are getting stuck in this track.
• February 9th
  • These updates incorporate feedback from the community to aid in assembly and also the reliability of the tracks.
  • All of the updates are minor and shouldn't impact anyone who has already printed this model.
  • In printing a new copy of this project to test the changes, I used Bambu PLA Galaxy and really liked how it looked - please see the GIF below.

  • Deeper counter-sink for screws attaching to the 'director' piece for a firmer fit. Reduced pressure on the motor (expansion of some filaments could cause too tight a fit) Added 'backstops' to the zig-zag runs to reduce the chance of balls skipping out of the track. Added an alignment notch for the split central screw used in the A1 Mini profile

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