Wooden marble run: how it works and how to build it

The Slotbok wooden marble run is a marble machine in a box. Turn the crank and a hooked wheel lifts the balls one at a time to the top; they roll along a two-rail track, run down a zig-zag and drop back into the queue to be lifted again. It is a toy, but it is also a working machine, with gears, a lift and a track that you can watch doing their jobs.

This guide covers how the marble run works, what each part does, how to build it, and a few things to try once it is running.

Watch it work

The 3D animation that comes with the kit: the box going together, then the balls going round. Just over half a minute. It also plays full-screen on the marble run assembly video page.

How the marble run works

One ball goes round the loop like this:

1. Turn the crank handle. The crank on the front turns the gears.
2. The gears turn the lifting wheel. Each gear passes the turn on to the next one.
3. The hooked wheel lifts one ball. The balls wait in a line on the queue track, and each hook on the wheel picks up one ball and carries it up.
4. The stripper finger takes it off. At the top, a small finger lifts the ball off its hook.
5. The ball rolls over the top and along the two-rail track.
6. Down the zig-zag and back to the queue. The ball runs down the zig-zag and drops back into the line, ready to be lifted again.

Keep turning and the balls keep going round, one after another.

The science in a marble run

Energy goes up, then comes down

When the wheel lifts a ball, the work you do on the crank is stored in the ball as potential energy: energy it has because it is high up. As the ball rolls down, gravity turns that stored energy into kinetic energy, the energy of movement. A little is lost to friction and to sound on every trip, so a ball can never roll back up to where it started on its own. That is why the machine needs the crank: you put the energy back in, one ball at a time.

Gears

Gears are wheels with teeth that mesh, so that one turns the next. Two meshing gears turn in opposite directions, and a small gear driving a big one makes the big one turn more slowly but with more turning force. That trade between speed and force is why machines use gears.

Slopes and speed

A steep slope makes a ball speed up quickly; a gentle one lets it roll slowly. The zig-zag makes the trip down longer, turning the ball back and forth so it does not build up too much speed before it reaches the queue.

What is in the kit

The Slotbok wooden marble run kit is cut by laser from 3 mm MDF or plywood, and every part is labelled. The parts map shows where each piece sits on its numbered sheet, so you can find it before you press it out.

The walls, the gears, the lifting wheel and the tracks all slot together, with no glue.

How to build the marble run

1. Watch the animation once. It shows the order the parts go on, and the finished box.
2. Press the parts out carefully. Work along the small tabs rather than forcing a part out of the middle, and use the parts map to check each one.
3. Push every tab fully home. The box only becomes stiff once all the walls are closed.
4. Check that everything turns before you add the balls. Turn the crank a few times: the gears and the lifting wheel should turn freely without catching.
5. Pour the balls onto the queue track and turn the crank.

If it does not run properly

• The crank is stiff or catches — check that every tab is pushed fully into its slot and that no gear is rubbing against a wall.
• A ball stops on the track — check that the box stands on a flat, level surface, and that the rails are seated all the way down.

Things to try

• Time one ball all the way round the loop.
• Count how many turns of the crank it takes to lift one ball.
• Watch which gears turn the same way as the crank and which turn the other way.
• Add one ball at a time and see how many the loop can carry before the queue fills up.

Each one makes a short science activity, if you are learning about energy or gears at school.

Frequently asked questions

What is a marble run?

A track for marbles or balls to roll down. A marble machine, like this one, also has a lift that carries the balls back to the top, so they go round and round for as long as you keep turning.

How does a marble machine lift the marbles?

In the Slotbok marble run, a crank turns a set of gears, and the gears turn a wheel with hooks on it. Each hook picks up one ball from the queue and carries it to the top, where a stripper finger takes it off and sends it down the track.

Do you need glue to build it?

No. The parts are laser-cut so that the tabs and slots fit together closely, and the whole box slots together.

Where can I buy a wooden marble run in South Africa?

The Slotbok wooden marble run kit is cut in our workshop in Gauteng and delivered across South Africa.

Get the kit

The kit is cut in our own workshop in Gauteng, and every design is built once by hand before it is packed, so the slots and tabs are known to fit.

• Wooden Marble Run Kit
• Wooden toys and marble runs

Like building things that work? See the build guides for the electromagnetic crane, which has a crank and a winch, and the hydraulic arm.

Questions about a kit or delivery to your town: message us on WhatsApp.