Introduction: How to Make a Ball Bearing Rollercoaster

About: cups of tea and cake fuel a collaborative environment in which we make electronic things and tinker in our workshop. We started FriiSpray, an open virtual graffiti project. Stuart, Richard + Dave We think th…

Scott had always wanted to make some sort of ball bearing rollercoaster and we thought we'd post up the results of his first testing and building sessions.

The idea was to make track for ball bearings (or similar) out of something that was fairly quick and easy to work.

Scott found that mains cable copper wire was perfect for this, go to the next step to see a list of ingredients for this project and get cracking.

It is assumed that you have access to a workbench / desk and that you can use tools like soldering iron, wire cutters and so on.

Step 1: Ingredients

A list of things you'll need for this project:

- Ball bearings (we used 5mm)

- Battery drill/screwdriver (ours is the cannibalised motor from an old one)

- Small drill bits (that match the diameter of the wire you will be using)

- Mains wire (we ended up getting a big roll but you can use the grey sort, often easy to get from skips or lying around. You'll want the stuff that is quite stiff, we found 2.5mm squared core to be best)

- Pliers / wire cutters

- Soldering iron + solder (we ended up modifying our soldering iron tip for best soldering)

- Small motor (ours is from and old zoom lens, you could maybe take apart an old CD drive to get the tray motor or similar - post up what you use)

- Spirit level/s

- Chipboard / ply board  (for jig and for mounting the rollercoaster)

- Matches (for jig)

- Glue (we used hot melt glue gun and some wood glue)

- Sharp knife (Stanley or similar)

Once you have this lot, you can get making!

Step 2: Straightening the Wire

 To ensure you get a smooth rolling track you'll have to straighten the wire before you start making (especially if you've acquired old bits from skips / other sources)

To do this, first strip a length of wire (~50 - 100cm)

Next affix one end to something fairly solid (like a vice, or a piece of wood you can hold)

Attach the other end to your battery drill.

Tension the wire by pulling the two ends apart, and spin the drill slowly. Don't go mad here - you will be able to see when the wire has twists in it and has straightened out.

Step 3: Making a Jig

 To ensure you can make consistently spaced track, a jig must be made.

To start, place a ball bearing on a piece of your board and cut two lengths (~10cm) of straightened wire.

Bring these pieces of wire together until they lift the ball bearing from the surface of the board. You might need to experiment a little here to get a good gauge (track spacing).

Next you will need to find something to stick on to the board to make your jig. We found match sticks to be a perfect size for the spacing of track so we got 3 match sticks and glued them to the board. You will need to ensure that the space between them is snug on the wire but not so tight that you can't move the wire up and down in the jig.

We started with standard length match sticks but soon found that we came across difficulties when trying to make more complex parts of track, like corners. We ended up chopping match sticks in half lengthways, this seemed to give us a workable solution.

Step 4: Track Making Basics

 Now you have a jig and plenty of straight wire you can start making some track.

It is best to start out with a few straights as prototypes before thinking about layout.

Place two straight sections of wire in the jig and cut some short 'sleepers' that you will need solder on to the tracks.

You will need to apply quite a lot of heat to this thick copper so we modified the end of our soldering iron for maximum heat transfer. 

You will need to make sure that you don't get any solder onto the surface of the tracks that will touch the ball bearing as it rolls. Again, practice here will help.

Once you have soldered your first track sleeper, slide the track up and solder your next sleeper on. Distances between each sleeper can be experimented with, a gap of ~5-8cm worked for us.

Once you have mastered the art of making track pieces, you can move on to corners and tricks!

Step 5: Corners and Tricks

 This is where track making can get a little tricky and requires yet more trial, error and more trial.

Start off by having a think about track layout - remember you are relying on gravity to get the ball travelling around the track. You can get away with very slight gradients to get the ball moving slowly. You can include sharper drops for loops and jumps but bear in mind that this will get your ball to the bottom of your track much more quickly.

Increased ball speed also means that some corners may need to include side barriers to keep the ball on the track. These are the things that you will find whilst building your own track.

Start off by trying to make a corner piece. Make a section of straight track with a few sleepers, then take the track out of the jig and convince round into as smooth a curve as possible with your hands. Do one track rail at a time.

Once you have something that looks pretty much right, put the straight at the other end back into the jig and solder on your sleepers. You can then add sleepers to the corner section too, making sure that you keep the gauge of the track as consistent as possible.

Test your corner out and see if the ball bearing runs smoothly around it. Once you have done this, start thinking about other sections of track to make.

Remember that you can make your track modular to a certain extent: make corners, straights, loops and so on individually. You can then start to assemble the pieces into a rollercoaster.

Experiment with different track pieces and peculiarities - loops and screws are fun. We also made a small jump with a cage to catch the ball bearing, and a swinging bridge in an earlier prototype.

Step 6: Making Ball Lifters

Scott wanted to make a roller coaster that didn't end. Once the ball bearing reaches the bottom of your track (the board) he worked out a way of lifting them back up. By doing this you can add in more track or send the ball bearings back to the start of your existing track.

Use multiple ball lifters for increased track length.

Making the ball lifters took many many prototypes - and slightly different styles may work better for your ball bearings / making technique. See the picture of all of Scott's different attempts.

The idea here is to make a screw thread from wire wrapped around a central piece of wire, then put this 'threaded' assembly inside a cage that allows the thread to push the ball bearing upwards.

You will have to work out some way of holding the rotating centre - Scott wanted to make as much of the track as possible out of the copper wire but you could try using other bearings/parts if you wish.

We found that an angle of ~35-60 degrees works ok, vertical lifting is quite hard and puts more pressure on the thread and cage.

Experiment with different thicknesses of wire for the thread. It will take a few attempts to get a nice smooth thread.

Attaching the motor: start by making a copper sleeve/adapter out of a tightly coiled length. Once wrapped around the motor shaft it will allow for a good solder connection point to the rotating shaft of the ball lifter. 

Step 7: Experiment!

Here is a picture of one of the finished models. You can see that vertical support wires have been mounted into the chipboard: this is done by drilling small holes into it and pushing the wire in.

Once you have started to put different modular components together and mounted them onto a board you will find that things may need slight adjustment / fettling.

Use a spirit level to make sure that your board is level before adjusting your roller coaster - this allows you to make sure it will work once you've moved it somewhere else.

Any problems then post a comment and we will try our best to help you out.

Good luck,

The Jam Jar Collective