Cheap and Simple Steam Engine

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. 




View on YouTube

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. 

Materials:

• 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

Tools:

• 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)

Plans:

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. 

Comments

[lost2010]

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.

[Billgun21]

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)

[Everett_McKinley]

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.

[MIRAMANALI]

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)

[egustys]

Best way using propseivers (last foto)

[Daniel Deacon]

you could also use a hacksaw but that might be abit more trikey and not get such a good finish

[akidrick]

how did you cut the ply wood

[Daniel Deacon]

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

[sam D]

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.

[planetroverrobo]

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?

[liam2317]

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.

[planetroverrobo]

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

[steve-lane]

(removed by author or community request)

[liam2317]

In the final picture on Step 8 you can clearly see how the air hose (it's the clear tube which is connected to the white plastic tube by a smaller, black piece of heat-shrink) is connected to the motor. You will not need to drill any holes in the brass pipe.

[steve-lane]

(removed by author or community request)

[liam2317]

You can download the PDF attached to Step 1 which is titled "Parts Only With Measurements.pdf" or you can get them from the attached image of the plans.
Here is a direct link to the large image of the plans.

[Sky Woulf]

if using seeam (bolier problems aside) you could use an old model airplane trick..... in a gas powered model airplane we coat our "wood" 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 "Any" 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!

[liam2317]

I think this would probably work quite well. If someone does try this I would definitely recommend coating the parts with epoxy either before, or as you assemble them (you could even use the epoxy coating to glue the parts together as well as seal them!).

[sbinc028]

what's the spring for?

[liam2317]

The spring is used to push the cylinder head piece up against the main body piece to provide a good tight seal between the two. In the pictures though, you can see I replaced the spring with a small elastic band that goes around the whole steam engine. The elastic seemed to work a lot more efficiently than the spring did.

[flowerman7]

Nice project! for the piston could you cast it out of J-B weld like many people do when building stirling engines. How airtight doues the pison and cylinder actualy have to be? Thanks

[liam2317]

I tried casting a piston out of epoxy as well but found that the brass tubes fit much better, were much easier to make, and seemed to have a lot less friction. My guess would be that it would still run if it leaked a bit but the more air tight the better!

[David97]

I have been talking to my teacher who has done a night course on building a steam engine. I have made 2 double acting engines to put on a model train.
I was going to run it with a boiler and a RC system. The boiler was going to be designed like a real one. Here’s what I thought of doing.

[David97]

I fogort to say the two engines would have a shaft between them to stop the steam taking the easyst route and olny going in circles

[GillesBathory]

the 2 pdf's "Parts Only With Measurements.pdf" and "Parts Only With no Measurements.pdf". The links dont work, how can i get them ?

[henrib736]

How many psi's does this run on?

[liam2317]

See the last step under the heading "Air Supply" for more info, but it runs well on ~15PSI.

[fuzzyguy]

The valve is tge 2 pieces of wood. as the piston is tilted by the crankshaft to the power stroke side it's 1 hole lines up with the hole conected to the air supply. As it passes by the bottom of it's stroke the 1 hole startes to line up with the other hole in the back piece. This hole allows the air to escape as the piston comes up. The spacing of the holes on the back piece are all important to how the engine runs.

[riverreaper]

could you vent the escapeing air in a way that it flicks it to start it ? sorta like the air compressor large in air to a fine out , simmlar to how they jet air to cut with only not that fine.

[liam2317]

I bet you could, maybe making some kind of little steam turbine like device could do it... hmmmm good idea!

[liam2317]

Thanks for the great description!

[DehLeprechaun]

first how would i hook up steam to it? second is it possible to hook 2 or more to one crankshaft? and third do you think it would work for a boat or car propeller/wheel respectively? thanks

[liam2317]

Unless you know what you are doing a steam boiler can be rather dangerous, even a miniature one. Be sure you do your reading and use the proper safety precautions if you do build one. Hooking up steam would be quite easy, just attach your boiler to the same port that the compressed air would normally be attached. As noted in the instructable using steam with an engine made primarily of wood will cause warping/swelling problems so replace with wood parts with something like aluminum. You should be able to add pretty much as many cylinders as you want, you probably wont get much more speed but you should get lots more torque. I think that this motor would definitely work in car or boat... or train. I am planning to eventually build one with twin cylinders using aluminum and putting it in a small remote control boat.

[riverreaper]

R/C Steam Turbine Tank is post in this sight

[DehLeprechaun]

i was thinking of making an rc boat/car using your method. torque was wat i was looking 4. one cylinder doesn't seem very strong.

[liam2317]

I think it depends a lot on how much your car/boat ends up weighing. As David97 mentioned adding gears to the motor to slow the output would be highly recommended, at least with a car. You might be able to get away without gears for a boat.

[David97]

You could try adding gears to the engine for more talk.

[Beergnome]

actually for a motor like this direct drive is just fine for a boat. for a car, a small spur on the fly wheel to a large sprocket on the Axle should work fine. just keep in mind that this type of engine is not self starting. hey liam? when ya gonna get that drill press going and make an updated one in metal? ;)

[liam2317]

I discovered that this engine will self start if you align the intake port with the cylinder's port before turning on the air... no flicking required, so it's kind of self starting. If you had a two cylinder version you could probably make it really self starting. WAY too busy with school right now to design/build anything. Hopefully some time in late August when I'm done school I'll be able to find the time to make one. A lot of other side projects on my plate right now though!

[riverreaper]

how do u stop it ?