The Idea:
Recently I saw a video of a remote controlled boat powered by a miniature steam engine and was instantly hooked on the idea. After doing a bit of research I found miniature steam engines cost hundreds of dollars or require some very advanced skills and tools to build. Yet looking at the actual mechanism which allows them to run they are really quite simple so I decided to try and make one on the cheap.

The point of this project was really to see how cheaply and easily a miniature steam engine could be built. I built this engine in one day and for under $10 in materials so I think it's safe to call it a success.

This engine is 7.2cm (2.8") tall.

Some Things to Note:
First off I should state that this steam engine is only a steam engine. This instructable does not include instructions on how to build a boiler to produce steam. Instead I run the steam engine on compressed air. If you don't have a compressor a bicycle pump works well too, it's just a lot more work for you. ; )

I should also note that even if you did build a boiler this engine probably wouldn't work well because many of it's major components are wood. In the presence of steam the wood would swell and warp causing problems. A simple solution to this problem would be to replace the wood parts with aluminum ones.

I am a very visual teacher so be sure to read the 'Image Notes' (hover your mouse over the yellow boxes on the images), it will likely make my instructions clearer.

How it Works:
You could read my lengthy description below or you could check out the totally awesome animation by the guys over at www.animatedengines.com, find it here! I should note that this animation is of a "double acting" engine, in that is has ports on both the bottom and the top of the cylinder where mine is a "single acting" engine with ports just on the top. This just means that the engine relies more heavily on the momentum of the flywheel to keep it running but is a lot simpler to build.

This type of engine is called an Oscillating Steam Engine. If you watch the video below you will see that the cylinder on this engine actually moves back and forth as the flywheel turns (it oscillates!), this action is what opens and closes the ports which let compressed air enter the engine and exhaust air leave.

The cylinder has one port at it's top which is pressed up against the main body of the engine. The main body on the other hand has two ports, one for the compressed air and one for exhaust. As the cylinder tilts to the right it aligns with the compressed air port allowing air to flow into the cylinder and push down the piston. This causes the crankshaft to turn, thus tilting the cylinder over to the left and allowing the air to exit the cylinder though the exhaust port as the piston comes back up. Then the process repeats.

Step 1: Materials, Tools, and Plans

Most of the materials and tools for this project you will likely already have around the house.  The only things I had to buy were the brass tubing, tubing cutter, and some wire. 


• 3/16" Plywood (aprox: 12x8cm)
• Retractable Pen (optional)
• Brass Tubing: (find some at your local RC hobby shop)
            13/32" for the piston and 7/16" x 0.014" for the cylinder
• "Tea Light" candle
• Heavy washers with a diameter less than that of the tea light
• 5 Minute Epoxy Glue
• Plastic Tubing (to connect your compressed air supply)
• HomeDepot sprinkler marker flags or piano wire (~18AWG)
• Floral stem wire or piano wire (~24AWG)
• Q-Tips with plastic tube (not paper)
• Small elastic bands
• Plastic Wrap


• Drill (or better yet; a drill press) and bits
Tubing Cutter ($5) - you should also be able to find one at most hardware stores.
• Pliers and Wire Cutter
• Empty Tin Can
• Razor Knife
• Sandpaper
• Vice (optional)


Attached are two PDF files.  "Parts Only With Measurement" includes a layout of all the parts you will need to cut out of wood as well as the lengths for the wire and brass tubing parts.  "Parts Only No Measurements" is exactly the same but without any measurements printed on the page; good for cutting out and gluing to your wood as a guide. 

Some people are having trouble opening the attached PDFs, if you are too try the links below. 

If you can't open the link to the PDF; here is a direct link to it.
If you still can't open the PDF; here is a link to a high resolution PNG image of the plans. 


Hi there. Thank you for putting this amazing "how to" guide on the internet. I am still in school and was struggling to find a project. I came across and knew this was the one! I appreciate all your time and effort put into making this work. My project turned out real good! Thank you once again :) Teco
Hi OP :D May I ask if this steam engine can be connected or modified to produce energy or electricity; or is this model not fit for the job??? Thank you!! I am greatly impressed with how your model was made. <br><br>Sorry for poor english :(
<p>It is pretty small and inefficient but you could do it. I have not tried it though so I can not tell you how much power you could expect to produce. </p>
I like your projecct very much and by the way can we use plastic pipe and piston inplace of metal.....
<p>Probably, plastic is not likely to be as perfectly round so you will probably have more friction making your engine less efficient. </p>
<p>I want to make this same thing but with steam power not air. I do not have any thing that will cut aluminum well. Do you think plastic will work?</p>
<p>Plastic would likely work just fine. </p>
<p>I am making a biogas plant that produces biogas (methane and other gases) and I want to convert this methane to produce electricity. How can I attach this steam engine and a steam boiler to the biogas produced to get electricity ?</p>
<p>How do I connect this steam engine to a steam boiler to produce electricity from biogas ?</p>
<p>Hi there ! l follow your nice tuto, and l even posted a video here:</p><p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/Sd1QBpg8kh4" width="500"></iframe></p><p> but l didn&quot;t want to buy anything, especially brass tubing, as l found an aspirin plastic tube just in the bin. So l decided to scale all of your plans on this plastic tube. That led me to make the whole &quot;engine&quot; 3 times bigger ! The piston is roughly 7cm long.</p><p>it took about an afternoon to make it. l screwed many pieces, l was too impatient for the glue to dry :)</p><p>on the flywheel, l added 4 screws to add some weight, don't know if that really makes a difference...</p><p>Next step is to plug that on a boiler or a compressor if l can borrow one !<br></p>
<p>Do you think a ninth grader could do this as a 40 hour project?</p>
<p>how can we connect this engine to a miniature car or a boat to make it run on this engine?</p>
<p>if I double the measurements and make the project bigger,will there be any problem?</p>
<p>Anyone know if this can pull any weight? I'm thinking of making a ride-able train for my niece and nephew; and I want to model it after the steam trains used in Walt Disney's Worlds' Magic Kingdom.</p>
<p>You could use the tea light tin as a mold to cast a lead flywheel. Lead is really easy to melt and cast.</p>
Excellent! Well done!
Hi, please fix your measurements, I'm from RSA, and where you said mm, we used millimetres, please make them RSA friendly plans
would pvc <br> work too<br>
<p>Do you think you could use a Dremel to cut it?</p>
<p>A Dremel would probably work fine, just be sure to take your time with it. You don't want to push too hard and deform the metal, it's very important that the cylinder and piston stay as perfectly round as possible. </p>
Sir so the system can only run by the air compressor if i use steam air sir is it possible sir thanks the response
<p>As mentioned in the instructions, you could probably run it with steam <br>just fine. The only concern is that the wood might become wet and swell <br> in size so you should likely either not use wood or find a way to make <br>the wood waterproof if you are going to use steam.</p>
Hey guys , i found this cylinder and piston from 12v air compressor , so can anyone tell me is it possible to make a steam engine with this
<p>Curious mate. What pressure are you putting through the pipe and would you have a clue as to how fast the crankshaft is spinning?</p>
how do you oscillate the air
Will it matter if the copper tubes are bigger diameter and height wise than those you showed.
I actually used brass tubing for this little engine, I bet copper will work fine too though so long as they fit together very closely and still move freely. The diameter really shouldn't matter much (within reason) so long as there is still a very close fit between the two. Height wise; unless you scale the other parts you will run into problems. Just make everything bigger to match the scale of your tubes and everything should work great.
Digging in my old broken VCR i found the video head and the first thing that popped into my head was &quot;flywheel&quot;. just a thought..
nice one .....:-) <br>
Umm I Know this is kind of late to ask but the last steps you wrote but there are no pictures. I think you probably did that because you were already done. But I don't quite understand how the final assembly goes together. Could you please add one or two more pictures just to clear up. Thanks
How is this a steam engine if you are using compressed air? this is a waste because its pointless to use a machine to run another machiine.
it uses the same principles as an oscilating steam engine so hence technically it is but as the maker said, a lot of parts are wood so if you want a genuine steam engine use metal.
it uses the same principles as an oscilating steam engine so hence technically it is but as the maker said, a lot of parts are wood so if you want a genuine steam engine use metal.
This is a steam engine, If you built a small boiler and everything to go with it it would run it just as well as the compressed air. But homemade boilers are risky and dangerous if you're not experienced. So using a air compressor is safer and easier (And cheaper)
but not as cool besides the boilers don't generally burst like a frag, their seams split and vent steam. sorry if you wanted shrapnel but chances are you'd just get burned.
hi this project looks really cool i am planning to use the basics to make one for a geared bicycle so that i can use its gears as helping hand for the engine(reducing the load). instead of a single acting engine i want to make a double acting engine but am confused whether adding one more inlet and outlet as above hole on bottom side of the plank will do the job? ,sealing the cylinder from bottom of course with the valve u have shown above and running the piston rod through the plank of that valve (the hole will be lined inside with rubber just to prevent air leaks because of piston rod)
Best way using propseivers (last foto)
you could also use a hacksaw but that might be abit more trikey and not get such a good finish
how did you cut the ply wood
cut the ply with a saw. cut roughly around where you need to cut. make sure you have drawn out the patten onto the wood exactly right then make a waste line and the exact line cut in the middle of the waste line and the exact line when this is done sand it down till it is perfect. make sure you don't go over the exact line or you will need to start over. it would be good if you used a small saw unless you are very careful. you could also use a copping saw or jigsaw but that might be abit more tricky
Love this build. White nylon cutting boards from the junk shop - which are high density PE might be an alternative for the wood. Low friction, good durability and high temp resistance.
I'm thinking about building a steam powered boat. And I like the idea of this steam engine but my idea of a engine is where there is olive oil burning boiling 2 quarts of water. when the steam becomes pressurized it will be pushed out of a two way valve so it creats pressure to push boat. But this engine has to carry a model boat, car battery, live camer, antena for radio control, ROV (which has camera on it), 200ft cable to power ROV, 200ft cable to carry information from ROV camera to model boat. Which engine would be better the one I thought about or the one liam2317 made?
Sounds like a pretty complex project already, may as well save yourself the trouble and just go electric. You would need a pretty big steam engine to move around all the things you listed at a decent speed. Unless you have a very specific reason for using a steam engine I would definitely just use an electric motor if I were you.
ok thanks. I'v decided to go electric any ways also I'v decided to take everything of what I listed. Instead I made a pontoon boat puting 4 D cells or C cells and a small solar panel to rechage batteries. Thanks anyways though
if using seeam (bolier problems aside) you could use an old model airplane trick..... in a gas powered model airplane we coat our &quot;wood&quot; engine compartment and fuel tank compartment and the firewall with painted on 30 min epoxy (find it at your local automotive parts store) and this completely seals the wood from &quot;Any&quot; moisture, solvents, etc. (also has high temp restance somewhere around 1300 degrees F i think) so if you were to coad ALL surfaces of your wood like that you could (I think) run low presure setam in this motor. then you could try to run it off a stovetop tea kettle with a stopper and a hose. just allow for the pressure to build before starting!

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