The Story Behind The Wall Marble Run

Human beings sometimes get strange ideas out of nowhere.

In my case, that happens quite often.

At the moment the idea appears, I’m absolutely convinced it’s the best idea I’ve ever had. But then… time passes. The excitement slowly deflates. And before I know it, the “greatest idea ever” has quietly disappeared.

I realised that if I kept going like this, I would never actually build any of my “best ideas.”

So I decided to do something drastic.

I would make it impossible to go back.

That’s how this marble run began.

This marble run is 1200 mm (47.2 in) tall and 600 mm (23.6 in) wide. It is mounted directly on the wall next to our dining table.

Yes. Once it was attached to the wall, there was no turning back.

 

Lifting the Ball: The First Challenge

The first problem was simple in theory:

How do you lift a ball up 1200 mm?

There are many possible methods, but for this height, I thought the most efficient way would be to use metal balls and lift them with magnets attached to a moving chain.

So, without thinking too much about the overall design, I started by building the chain.

 

Preparing the Base

Before attaching the main board to the wall, I milled shallow holes into it using a CNC router, creating a grid pattern almost like graph paper.

This was an idea from my woodworking mentor, Juno.

It makes positioning parts and placing screws much easier.

 

 

Three-Gear Vertical Lift (a.k.a. The Hardest Part)

Once the base was ready, I wanted another lifting mechanism besides the chain. Using only a chain felt a bit boring.

So I decided to use three large gears.

The material? Leftover wood from making puzzles.

If you look at marble runs on YouTube, you’ll often see gear-based lifters where the gears are tilted, or where boards cover the holes so the ball doesn’t fall out.

But doing the same thing as everyone else is not very interesting.

So I stood three gears vertically? with no guards at all? and tried to design a system where the ball would travel all the way up.

This was the beginning of a long period of trial and error.

Making the ball fall only at a specific point was surprisingly difficult. And not only that ? it had to land precisely into the hole of the next gear.

This was the most challenging part of the entire marble run.

Here you can see the chain and the triple gears installed on the base.

 The Wall Marble Run, January 2023

Adding a Shishi-odoshi

One element I really wanted to include was a shishi-odoshi.

If you have visited a Japanese garden, you may have seen one.

It’s a bamboo tube that fills with water, tips over to empty itself, then returns to its original position. When it tips, it makes a distinctive sound. Originally, it was used to scare wild animals away from crops, but today it is often decorative.

In my marble version, the ball replaces the water. 

The Momentum Loop and My First Time Using a Lathe

If the ball is going to roll with energy, I thought it should also feel a bit like an amusement park.

That’s how the loop was born.

However, I had no idea how to machine this shape using a CNC router. Once again, my mentor Juno came to the rescue.

Where the ball jumps, it lands in a trumpet-shaped piece that I turned on a lathe. It was my first time using a lathe, so I was slightly nervous.

More Parts, More Experiments

At the bottom, I created a storage area for the balls. Since I was making it anyway, I decided to use marquetry.

 

There are many ball-distribution parts in this marble run, but the most numerous elements are the rails.

Straight rails are functional but not very exciting, so I experimented with curved rails. Luckily, I happened to have just the right router bit and cut them horizontally with the CNC.

Next came the spiral drop section? slightly reminiscent of the Guggenheim Museum. I named it Helix Honey Dipper.

This was machined using a rotary attachment on the CNC router. Once again, Juno helped.

In the upper right corner is a vertical mechanism made of arrow-shaped pieces (Cascading Arrow Tilts) that pass the ball downward one by one. Surprisingly, transferring the ball smoothly between parts was quite difficult.

Actually… almost everything was difficult. 😅

 

The Wall Marble Run, May 2024

Vertical Splitter distributes the ball left and right. It’s similar to a typical Y-shaped splitter, but oriented vertically. At first, it didn’t work well until I placed two balls inside. Then it behaved perfectly.

 

The Wall Marble Run, September 2025

Open Frame Rail is a rail located high up. If it were a normal rail, it would be hard to see from below, so I designed it so the ball rolls visibly inside a frame.

Mosquito Coil Spiral is similar to the round dish element, but since it is also positioned high, I left openings so the movement of the ball can be seen from below.

 

Rotary Catcher receives balls from two directions. To prevent jamming, I used bearings for the centre shaft to ensure smooth motion.

Three Years and Eight Months

If I described every detail, this marble run would include more than 30 parts.

I worked on it whenever the workshop was available, so progress was slow. In total, it took three years and eight months to complete.

If I hadn’t mounted it on the wall at the beginning, I might never have finished it. 😆

  

From here on, I would like to continue exploring not only marble runs, but also automata and kinetic art.

This project started as a strange idea.

Now it lives on the wall.

And it moves.

Jack the Jackhammer – Wooden Automaton

Happy New Year!
I hope 2026 will be another creative year for all creators.

For the first post of this year, I'd like to introduce a wooden automaton.
I like automata, but I haven't made many of them. In December 2025, the workshop was quiet on some days, and I saw it as a good opportunity to make one.

I wanted to keep the project simple. The idea that came to mind was a jackhammer. Many automata are fantastic and pretty - flowers, butterflies, and other gentle things. A jackhammer is none of those. It's loud, rough, and definitely not elegant.
That was exactly the point. 

The motion of a jackhammer is very similar to the up-and-down movement produced by cams. With that in mind, I designed several parts using 3D graphics software and printed them with a 3D printer.　Here is the 3D-printed prototype. 

At first, I planned to use two cams on separate, parallel shafts. However, that design required gears to keep everything moving together. Since my goal was simplicity, I rearranged the cams so that gears were no longer necessary. Fewer parts, fewer problems - at least in theory.

The most important part was getting the jackhammer's movement right. I made several serrated cams and tested them again and again.  

The cam for the jackhammer has large, jagged waves to create a strong impact. The other cam has smaller waves, just enough to animate the worker bravely operating the machine.

After many trials and errors, I finally completed the automaton, which I named Jack the Jackhammer.

It's not pretty, it's not quiet - but it does its job.

 

My Challenge to Make a Marble Run Machine - Improving Parts

Back in April 2022, I started building this marble run - and somehow I’m "STILL" working on it. Honestly, it amazes me (and sometimes frustrates me) how much time it's taken. Of course, I don't work on it every day. I only get to build when the workshop is free, so there are often months - long gaps in between.

Recently, I finally made a bit of progress, so here's a long-overdue update. Some of the parts I built earlier didn’t work the way I hoped, so I decided to remake them. 

1. The Switch

First, I rebuilt the “Switch,” the piece that splits balls into two directions (one to the left, two to the right). The problem was, if too many balls dropped at once, it didn't always work properly. So I redesigned it, and this time I also cut a little window on the right side so you can see the balls inside when they fall through.

2. The Bottom Rail

Next, I fixed the bottom rail. This is where balls wait in line before being lifted up again.

Originally, I made it in a zig-zag shape. Since it looked a bit like the letters “CNN,” I jokingly called it the “CNN rail.” But there was an issue: when balls piled up, the ones at the back would push the others off the curve, and sometimes they fell out. To solve this, I changed the design from a CNN shape to a paperclip shape.

Here's the tricky part - I'm not great with loops, and I wasn't sure how to cut this shape on the CNC router.  

So I asked my woodworking mentor (aka my husband) for help, and together we made the new rail. Since switching to this design, no more balls falling out!

3. The Pachinko Disk

The third part I fixed was the “Pachinko Disk,” named because it looks like a Japanese pachinko machine.

The idea is that when a ball drops in, it hits screws or walls inside and makes the disk spin. But the disk was too heavy compared to the balls, so it didn't rotate very well. The placement of the pins and walls also affects the motion a lot.

This time, I designed a lighter version and printed it with my 3D printer (PLA plastic). To my surprise, it spun beautifully once I installed it in the marble run. Probably thanks to the lighter material.

 

I also swapped out the heavy screws for bamboo skewers (yes, the kind you use for BBQ) and wood. That made it even lighter, and now it spins much better than before.

This is the finished Pachinko Disk. 

 

That's all for this update! Next time, I’ll write about some of the brand-new parts I've been working on. Thanks so much for reading!

My First 3D-Printed Marble Run

I haven’t updated this blog in a long time. One reason? Our house got some renovations. Before it all started, I had this nagging feeling something might go wrong - no concrete reason, just a hunch. And I was right! A bunch of unexpected issues popped up, and the whole thing dragged on much longer than anticipated. It finally wrapped up in December. So, I’ve got a good excuse for not finishing my marble run yet. Hehe.

After the dust settled, the first thing I made was a miniature marble run. I thought, "Why not make a Christmas tree with a spiral for the balls to roll down?" It sounded fun and festive!


I drew a few Christmas tree designs in 3D software, aiming for something tall and impressive. But, if the tree got too big, printing the spirals would take forever, so I had to strike a balance.

 

 

 

Printing the spiral part alone took 8 hours and 10 minutes! With a cone-shaped spiral, you need supports to keep it steady, which adds to the printing time. Unfortunately, the project wasn’t finished by Christmas, but it was finally completed in 2025, and I’m happy with the result.

 

 Here it is - my very first 3D-printed marble run! 

I wanted a polyhedral star on top, so I enlisted my husband, Juno to design it. Inside the tree, there’s a spiral post that can lift multiple balls from three different sides. It’s simple, but I’m thrilled with how it turned out. Like a kid, I can’t help but crank the handle several times a day. If I find some colourful glass marbles, I’ll swap out the metal ones—they’d make the tree even more festive.

Now, what should I make next with my 3D printer?

The 3D Printer

I finally bought what I had wanted: a 3D printer. Initially, I assumed 3D printers would be challenging to use. However, after watching people on the internet using them, I began to feel it might be easy. Then, something nudged me: a second-anniversary sale at Bambu Lab. By the time I noticed, the sale was about to end in a week.

"All right! Now's the time to buy it!"

I bought a Bambu Lab P1S 3D Printer, four filaments, and a 0.2mm nozzle. 

I immediately began creating shapes using 3D graphic software. It was exciting, but unfortunately, the COVID virus disrupted me. Suddenly, my motivation dropped, and I was unable to work due to illness. It took about ten days to recover. It was an awful experience. While I had a fever and was too sluggish to move, I could only stare at the ceiling and envision new designs for the 3D printer.

I recalled an idea I'd long imagined—it was the perfect time to bring it to life. The 3D printer is more accessible than a CNC router for realizing my ideas. Unlike the noisy CNC router, which restricts night use, the 3D printer offers convenience at any time. How convenient!

The 3D printer also proved handy for creating new jigs. My husband asked me to make some jigs for the CNC router. Making them from timber would have taken much longer, whereas the 3D printer produced them quickly. We should have purchased a 3D printer sooner indeed.

I plan to showcase my 3D-printed creations here someday.