Introduction: Wooden Marble Coaster - From a Single 2x4
I love roller coasters. Especially wooden ones.
To me, they are the epitome of functional art. The timber frameworks are mesmerizing feats of creativity in and of themselves, aside from the fact that they are built so people can zip along in a little car on a track on top, under, and through them. Modern metal and hybrid coasters are fascinating as well, but the old wooden ones have a special appeal to many people, me being one of them.
I also love rolling ball sculptures, and kinetic art in general.
A few years ago I made a pretty neat marble coaster out of cardboard. Ever since then I've often thought it would be fun to make another one, but this time completely out of wood and styled to look like a classic wooden roller coaster.
This is the realization of that idea, and I'm happy to report that this wooden marble coaster works great and was incredibly fun and satisfying to make.
The highlight of the build for me is the solid wood Archimedes-screw-type lift that transfers the marbles back to the top of the track for continuous rolling action.
And just to keep it interesting, the entire thing was made from a SINGLE 8-foot two-by-four!
Come along and see how it was made, and then perhaps go and make your own. Thanks for checking this out!
Step 1: Video
Here's a video of it in action. The first half shows a couple cycles of the marbles running the track; the second half is a quick slideshow of the build.
Step 2: Tools and Materials
For those unfamiliar, a "two-by-four" (written hereafter as "2x4") is a standard board used in building construction in various locales that is actually 1 1/2 inches by 3 1/2 inches (38 x 89 mm) and is available in various lengths. One of the most common lengths is 8 feet (2.44 meters), and that is what I used for this project.
At my local hardware store, I dug through the pile of 2x4 boards until I found one that was mostly knot- and blemish-free and had a fairly consistent straight grain.
An old toy drill was appropriated from my children to hack apart for its motor assembly and batteries to run the lift mechanism.
The marbles used for this are actually the tracking balls out of a couple of old computer mice, with the rubber coatings removed.
Tools used were a band saw, table saw, spindle sander, small rotary tool with sanding drums, hot glue gun, an x-acto style hobby knife, and some sandpaper.
Step 3: 2x4 Initial Break Down
After making a basic plan, I broke down the 96-inch long 2x4 as follows:
- One 32" board. This will be ripped into four equal 3 1/2" wide slats to be used for the base.
- Two 20" boards. These will be ripped into several thin 1 1/2" wide slats to be used for the track and various support pieces.
- One 24" board. Half of this will be used to create the wooden Archimedes-type screw, and the other half will be split into long strips to use as vertical supports for the track.
Step 4: 32-inch Piece
The 32-inch piece was first run through the table saw and a single blade-width of material was removed from an edge in order to ensure a flat face to put onto the table of the band saw.
The board was then split into four equal slats with the band saw. See photos for notes on this process.
Step 5: 24-inch Piece
The 24-inch piece was split into two 1 1/2" by 1 1/2" pieces.
One of these was ripped into 20 little strips on the band saw, and the other was carved into a screw for the lift mechanism (covered in next step.)
Step 6: Carving the Screw
To create the wooden screw, I began by cutting the corners off of the 1 1/2" by 1 1/2" piece left from the previous step. This was done with the band saw. The little strips that were removed were kept to be used later on as additional support pieces.
I then used a rough carving bit to knock down the remaining eight points till I was left with a somewhat roundish cylindrical stick. (This step could have been simplified with a lathe, but I am currently lathe-less with no plan to acquire one any time soon.)
I wrapped some tape around this in a spiral fashion, leaving about a 1/2" spiral gap of bare wood between the edges of the tape. I then spray painted the bare areas and removed the tape. The painted areas became the threads of the screw, and the bare areas were carved away to make the valleys. This carving was done with various bits using a rotary carving tool.
Step 7: Two 20-inches Pieces Become a Plethora of Thin Slats
The two remaining 20-inch boards were carefully ripped into thin slats on the table saw. I was tempted to do this on the band saw with its much thinner blade (in order to not lose so much material in the process), but ultimately decided it was worth the loss of some material to have consistently smooth and flat little slats. So table saw it was.
Each slat was cut to the left of the blade, with the fence moved incrementally to the left after each pass. All cuts were done using a pair of push sticks.
When I got down to about a 1/2" thick piece remaining from each board, I used the band saw to split these final two pieces into halves. I wasn't comfortable running these through my table saw (as I have yet to make zero clearance insert.)
When it was all done I was left with twenty-six 1/8" slats, and four 3/16" slats.
Step 8: There Was Shrinkage!
With all of the pieces cut and ready for assembly, I decided to take a break from this project for a couple weeks to work on other stuff.
This turned out to be somewhat beneficial as all the cut pieces began to dry out quicker and shrink. This resulted in some cupping of the larger slats and a little curving on some of the smaller pieces. Although the movement was minimal, with a small and delicate structure like this I figured it was better to have the pieces acclimate and change shape before assembly rather than after.
The wooden screw gave me a little bit of a fright, however, as it bowed substantially and I was worried that it would no longer work as planned. As it turned out, it works fine (although you can see it "bounce" a bit from the bow in it as it spins.)
I'm curious to see if there will be much change in the wood over time as this sits in my house. As for now it is fine, but I'll be watching it to see what happens. This is all part of the fun of using a pretty green and wet 2x4 for the material!
Step 9: Assembly of Base
The base was assembled using the four large slats and two of the thicker slats created from the 20-inch boards.
The finished dimensions of the coaster base is 32" by 13 1/2" (narrower width than you'd expect due to shrinkage across the grain.)
The smaller slats used for the legs of the base were hot glued in place using copious amounts of glue. The large slats themselves were not glued to each other, but only to the legs.
When the project was completed I had one of the thicker slats from the 20-inch boards still remaining, and it was used to create triangle supports for these legs.
Step 10: Modifying the Toy Drill
This toy drill turned out to work perfectly for this project, as it was geared to spin and just the right speed for this application.
The drill was disassembled and the case was cut apart with the band saw. Various other small modifications were done and it was ready to go. See photo notes for more detail.
Step 11: Wooden Screw Completed
The bottom side of the wooden screw was cut and trimmed to fit into the parts from the drill.
A small piece of metal rod was inserted into the upper end of the wooden screw.
At this point I added some red paint to the screw to brighten things up, and sealed it with numerous coats of lacquer (I wanted to try to keep it from bowing any further.) The screw was then polished with a coat of furniture wax, on the thought that this might help the marbles move up it a little smoother.
Step 12: Building the Lift
Now, this is where things got exciting!
Up to this point, the entire functionality of the piece was still up in the air from my perspective. If the lift proved to work successfully, then rest of the project would be relatively smooth sailing.
I began by creating a tower to hold the top end of the wooden screw. Bits of wood were trimmed with the band saw as needed and glued in place with hot glue.
The motor assembly was mounted on a small base, and after some trial and error I decided on an adequate position for the both the motor and the tower. These were glued in place, and the screw was mounted between the two.
The balls ride up the wooden screw by resting against a rail that was installed to the side of the screw. This rail was carefully polished with wax to help reduce any friction.
Due to the slight bow in the screw, every turn moves it just nearly far enough away from the rail at the midpoint that the balls can almost drop through.
However they don't, so it worked out!
Had the bow been too much (or should it become so over time) other options would be to have a small track on the bottom of the screw for the ball to ride up in, or even two short walls directly above to hold the balls in place.
These options seem like they'd be more forgiving of any unwanted lateral movement of the screw, however, the side rail option works well enough for now and allows the marbles to be more visible to observers, which I prefer.
Incidentally, if I had built this to have the balls ride up a track on the underside of the screw (or if I had enclosed the screw in a tube) this would be more true to the original water-lifting Archimedes screw mechanism.
Step 13: Track Idea #1
With the lift mechanism working successfully, the next obstacle was figuring out how to make a track out of the wooden slats I had cut.
I toyed with the track idea shown here. The side rails and bottom section were cut from the same single slat, with smaller bits glued in place to hold the railing up just to the height of the midpoint of the marbles.
I really liked this idea and the way it looks, but it seemed like much more work than I was willing to do at this point. However, it is an idea I'd like to pursue should I ever attempt to make another wooden marble coaster.
Step 14: Track Idea #2
This option seemed easier, so this is the one I went with.
The track is made by gluing together two 3/4" strips into a V shape. The strips were made by simply cutting the thin slats from the 20-inch board in half with a band saw.
I made a little jig out of a large paint stick to hold the strips as I hot glued them together down the middle.
I ended up using about a dozen V-shaped sections like this to complete the entire track.
Step 15: Begin Laying Track
Pieces were hot glued in place to create and extend the track one section at a time.
To make curved sections, I used my band saw to cut out several small wedge shaped pieces from the the straight sections made in the last step. This is done with the section of track upside down on the band saw table so it is stable, and simply running it through the blade at a slight angle.
I used a spindle sander to occasionally sand off a little here or there on the pieces to adjust the fit and angle, but I didn't get too technical about it.
I could have tried to make compound cuts and make large banking turns and such, but for this first attempt at a wooden track I just kept it simple with a flat track and gentle turns. The balls don't travel fast enough through the relatively bumpy transitions to necessitate banking turns, anyhow.
Step 16: More Track Laying
The track was continued piece by piece on a gradual downward slope.
After my initial grandiose plans for speedy banking turns with swooping hills and loops gave way to reality (and the constraints of my experience and present level of determination...), I settled for just trying to create a steady pace where the balls wouldn't come to a complete stop.
The layout was just made up as I went along, although I did try to look at least a few turns ahead to make sure there was a nice flow to it.
Vertical supports were added as needed along the way to secure the track just well enough until it was completed. More sturdy permanent supports would be built all around to lock everything in place later on, and create the desired "old wooden roller coaster" look.
Some ideas didn't work out so well, so there were a few instances where I had to do some literal backtracking (see photo 4.)
Step 17: Finished Track Layout
Here is a shot of the finished track, before adding all the permanent supports.
Step 18: Adding Vertical Support
I added more vertical supports, so there was a post about every three inches or so along all sections of the track.
Step 19: Sort Out and Plan for Use of Remaining Material
At this point I took most of the remaining wood and cut it into small pieces to use for cross braces to lock all of the vertical supports together. I was a bit nervous that I would run out, but luckily ended up having enough, and a little bit to spare.
Step 20: Adding Framework Cross Members
This is where it finally started to look like an old wooden coaster. Adding these cross members was a fun little exercise in engineering, as they really did transform the wobbly track into a rigid, solid form.
I started on the backside of the coaster adding diagonal cross members between the vertical supports. At first, I just randomly glued them in place, but as I worked to the right and moved around to the front, I began to establish a more uniform looking pattern.
By the time I got all the way the right side of the front of the coaster, I had figured out how to make it look really nice. If I were to make another one of these and apply all the things I learned with this one, the resulting piece would surely be much, much nicer.
Step 21: Little Details
With all the track supports in place I took the remaining bits and pieces of wood and made various signs to decorate the track and make it more roller coaster-ish.
That's it! This was really fun project, and turned out much better than I had expected. I will certainly be making another all-wood coaster at some point.
If you happen to ever make an all-wood marble coaster, please be sure to leave a comment and photo! I'd love to see your work and hear any feedback on what you learned, new techniques you used, or any awesome features you incorporated.
Thanks for taking a look at this!
Step 22: What Can You Make?
What can you make (or have you made) out of a single 2x4? I'd love to see it in the comments below!
If you make something cool out of a single 2x4 and post a fully detailed, new step-by-step instructable to share the process, I'll send you a code for some free pro membership to the site! If the project is especially impressive, I'll sent you an instructables t-shirt!
This is a standing offer. Feel free to take me up on it at any time! Just post a link to your new instructable in the comments below.
I can't wait to see what you make!
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