12V Solenoid Beam Engine, Built From Aluminium Scraps and Scavanged Componants.




Introduction: 12V Solenoid Beam Engine, Built From Aluminium Scraps and Scavanged Componants.

About: no longer active.....

This is how I built a little beam engine powered by a solenoid which runs on 12v DC.

Due to the harsh winter I have been stuck in the house most of the time over the last few months, before Christmas I gathered up all the old hard drives, CD ROMS, Floppy drives, a zip drive, 2 printers, a flatbed scanner and a video recorder that where no longer working or no longer any use, after a couple of days of dismantling all this i was left with several boxes of very well made components to be put to use in other projects.

I decided that if i could not venture out into the shed, then the shed must come to me.  So I setup a work bench in a corner of my computer room and brought the piller drill and a selection of hand tools in out of the cold.

I bought a decent 6" combination square with scriber for this project, I have a 12" version of this already but the smaller one is much easier to work with on smaller projects.

I visited Banbridge Coach Works a month or so ago and asked if i could buy some of their cuttings of aluminium, I gathered up an armful of various pieces and was asked for £15 which I gladly payed. 

Many years ago when I was an engineering student I built a model steam engine as my end of year project which earned me a distinction.  Since then I have had a love for all types of steam engines.  In more recent years i have become fascinated by sterling engines and more recently solenoid engines and Froment engines.

This is my first real project that has mainly used aluminium, back in the day we used very little aluminium as it was much more expensive than steel and was an absolute bugger to weld.  I recently discovered Durafix Easy Weld rods which is a low temp welding rod for aluminium and non ferrous metals.

Design wise this project just sort of happened, it followed no set plan other than I wanted it to have a walking beam as part of the mechanism. because of this there are some stages that I don't have pictures of, there where a few dead ends on some of the stages but then again certain failures led to better ideas.

Materials used:

1" x 1" alu angle
3" x 1" alu angle
6 x 6 mm alu bar
5mm alu plate
3mm alu plate from an old Hard drive
20 x 15mm alu channel

10 x 5 x 5 roller bearings (RC car type)
12v solenoid from an ancient telephone switch board.
various nuts bolts and washers
various components salvaged from old computer and household tech goods.

Tools used:

Almost every thing I have, including the bathroom sink ( which required quite a bit of cleaning afterwords )

Pillar drill
Drill vice
Band saw
sanding table
Dremil type thing

Durafix rods
Blowtorch with propane / butane mix gas

Hand tools, including
Junior Hack saw
numerous small files
numerous needle files
6" combination square
tap wrench and taps.

2 part Epoxy

I had planed to make a governor for this engine and also to try and power it with a solar panel, for now the project is finished, I will continue tinkering with this engine and will post any modifications I make as they happen.

To save much typing there will be a brief description of each stage, the bulk of the info will be on the photos.

Thanks for looking, I hope you liked my design

Step 1: What Is a Solenoid Engine.

The solenoid engine or electromagnetic engine also known as a pulse motor was the forerunner to the modern electric motor. the following is taken from The Old Model Company who sum it up much better than I can


When Michael Faraday in Great Britain and Joseph Henry in the United States both discovered electricity at roughly the same time no one knew what to do with it because in those days nothing worked on electricity.

In the thirty or so years that followed, between 1831 and 1861, the great experimenters of the day tried to use this new discovery by copying steam engine design and practice.

Many early electromagnetic engines were of reciprocating design and used connecting rods, beams and flywheels that had to be constantly accelerated.

These early reciprocating engines were quickly followed by revolving armature designs of which Paul Gustave Froment’s was the first in 1844. These were much more efficient and a variety of different and increasingly sophisticated designs emerged.


To fully understand the unique properties of the solenoid engine you need to track down a copy of Secrets of the Electric Motor (it out there on the interwebs if you know which stone to look under)

This video is a scientific lecture is not for the faint of heart as it  kicks some major science re many of the properties of the modern electric motor that we just take for granted because we know the motor works rather than learning why and how it works.

I lost my only copy of this video so I'm a very rusty on the topic, but if you can find this video you will learn allot maybe even more that 1 brain can handle. the video explores work by Tesla plus the other great minds of that golden age and more recently John Bedini who's motor has achieved over unity (if you mind is open enough to believe such things)

I intend to explore the world of the Bedini motor as part of a future project once i get my lathe operational and my engineering tolerances back down to those i was once capable of back in the day.

Step 2: Why Built It?

Why not?

I built this for the following reasons.

To see if I could

To rekindle many of the skills I have let lapse in the years since I was an engineer by trade.

To indulge myself my fascination with all things of a mechanical nature. (but not the internal combustion engine, I have no interest in those at all)

To educate myself re electronics.

To build something that incorporates many of the features of the steam engine (Steam engines are my idea of engineering bliss) without the danger of fire and high pressure steam.

But my main reason for this project was to give me an indoor project to keep me occupied through this very harsh winter, something more fulfilling than spending the next few months in a prescription drugs based haze waiting for the spring to arrive.  (  PS. I'm still a bit hazed on it at times but at least I'm doing something better than sleeping)

Step 3: The Base

Until the engine was complete I used a scrap of 20mm plywood as a base, this alowed me to reposition the various components as i went along.

The display base was cut from an old pine bed frame using the bandsaw and then sanded on the sanding table.

Step 4: The Flywheel and Crank Shaft.

The first thing I built was the flywheel assembly.

The flywheel started out as a motor from a video recorder.

The ring magnet and coils where striped out just to leave the flywheel and bearing.

The crank was made from a brass spindle from a CD ROM drive and screw out of  a rubber damper also from a CD ROM drive.

The flywheel was mounted on a piece of 3" x 1" alu angle.

A platter from a 2.5" Hard drive was used to face the flywheel and was glued on with 2 part epoxy.

Step 5: The Beam.

The beam was cut from a cutting of 5mm alu plate.

The beam is 5" long x 1" wide. the beam tapers from the center to the ends.

The beam was marked out first and then cut out on the bandsaw and ground to shape on the sanding table.

The beam was not originally designed to take bearings but just bolts, I discovered I had some bearings and used them as the eliminated all the play that the original bolts had.

I applied a thin film of superglue into the holes with a toothpick and then pressed the bearing into place.

Step 6: The Tower

The tower started out as just to brackets made from 3 x 1 alu angle, this was mounted on a wooden block to raise it up high enough.  Then i discovered some 20 x 15mm alu channel in one of the sheds and used that  to make the bottom of the tower, the base was cut from a 3mm alu plate from an old hard drive.

The components where drilled mainly for cosmetic reasons but some are placed to aid in the task of clamping the pieces together before they where welded together.

The tower is welded using Durafix easy weld rods, i will not cover this now as I still getting the hang of this amazing stuff, I plan to do a Ible on how to use this stuff to its full potential in the near future.

The tower is approx 5" high.

Step 7: Trial Erection (fnarr Fnarr)

Back in the day our engineering instructor was taking us for a theory class, He told us that he would allow us five minutes to get all the laughing and jokes over with about the next engineering term he would use, he then told us about trial erections (fnarr fnarr)and indeed we di need the 5 mins before things settled down again.


With the tower and beam in place on a scrap piece of plywood, i was able to mount the flywheel in the right position.

I used light gauge wire as temporary linkages, these help in deciding where the flywheel etc will be placed.

The original solenoid was a small plunger type one that was just to small and over heated very quickly,  I then decide to use the large hinge type solenoid from a telephone switch board, I runs well on 12v but would probably have been 50v.

I had toyed with mounting the solenoid so that the flat would be pull the linkage directly down but then the mechanism would have to lift the weight of the flap and that would kill the momentum so I deiced to go for the overly complicated L shaped linkage.

Step 8: The Solenoid.

The solenoid i had planed to use was way to small and over heated in seconds, so when I discovered i had this one in the shed i used it. 

I was going to mount the solenoid with the flap on the top so it pulled the linkage directly down, but then the flap would have to be lifted back up with the momentum of the flywheel. 

The decided to mount the solenoid with the flap mounted vertically with hinge at the bottom, this way less effort would be used to return the flap to the open position.

Step 9: The Overly Complicated L Shaped Linkage.

This linkage transfers the horizontal action of the solenoid into the vertical action used to lift the beam.

I don't even know if I could explain how I made this.

You should be able to get the idea from the pictures.

I watched almost all the episodes of Sons of anarchy series 2 while making this, I could have made a simpler linkage but this was more to see how good the Durafix welding rods where.

Step 10: The Linkages.

The ends of the  long linkages are made from 1" alu angle and are joined with a 3mm machine screw with the head cut off, nyloc nuts where used to secure the end to the threaded bar.

the end that runs on the crank pin was bushed using Durafix, the hole was drilled over size and then filled in with Durafix which has a very high tensile strength so it will wear much better than the standard aluminium. the weld is then filed flat and re marked and then drilled to the correct size.

The square end of the long linkage was made from 6mm square alu bar filed to be a sliding fit for the L shaped linkage.

Step 11: The Contact Switch.

The contact switch started out as a spring loaded rocker switch that is found on most CD ROM drives.

A 4mm nyloc nut was attached to the switch using epoxy putty, once it had cured it was filed to shape.

The metal clip from a pen was used to extend the lever of the switch so it will take less effort to move the switch.

The clip was attached to the switch by crimping it slightly so it was a snug fit, then a small blob of hot melt glue was applied to the clip and it was pressed into position while still hot.

to make the cam a small nylon pulley was drilled out to fit the shaft and a screw was used to act as the cam.

Step 12: Wiring Diagram

Its not rocket surgery.

Step 13: Final Assembly on Display Base.

The base was marked with a lateral center line using a water soluble pencil.

First the tower is fixed in position.

With the tower and beam in place the crank linkage is fitted and this then determines where the flywheel assembly is fixed in place.

With the beam in the horizontal position the position of the L shaped linkage can be established.

Finally the solenoid can be fixed in position, making sure that the mechanism runs smoothly. 

Step 14: Finished at Last.

And there we have it.

I hope the Instructable made sense.

I may come back to this engine at a future date to do some slight tweaks, but to be honest I'm kind of sick of it now. I will try and make a better cam and contact switch though.

If i do make any changes I will post details.

I am going to build a Froment engine as my next project once I get my metal lathe going.

Thanks for looking and I hope you liked my ideas.

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    6 years ago

    Pretty neat. As a mechanical engineering grad who programs for a living, I getting my hands dirty cutting up metal. However, I do have an issue with your circuit diagram. You need a diode across the solenoid to protect the switch.

    Let's go back to Physics 101. The voltage across a coil is V = L di/dt. When your cam opens the contact switch, current drops to zero instantly. This instant change in derivative means the voltage across solenoid must spike to inifinity. Since we can't have that, what really occurs in the physical world is that current keeps flowing for a short while by arcing across the contact switch. This arcing will eventually erode the switch.

    To avoid that current jumping over an opened contact, you need to add a diode (aka flyback diode) that allows the current to flow from the negative end to the positive end of your solenoid.


    6 years ago on Introduction

    how can i download this pdf..???

    if any one help me then i will be vry greatfull to him/her,,,


    8 years ago on Step 14

    This is a good project. Can i have some advice on using the solenoid actuator to open and close a drawer.

    Dr Qui
    Dr Qui

    Reply 8 years ago on Step 14

    No..... Google would be the place to look.


    8 years ago on Introduction

    When you mention the "Secrets of the electric motor" video, is that its actual name?
    because i found one by dr lindemann that is called "Electric Motor Secrets" and im not sure if its the same one or not

    Dr Qui
    Dr Qui

    Reply 8 years ago on Introduction

    Yes that's it, the lecture is by Dr Peter Lindermann, the torrent I found was labeled as "secrets of the electric motor" but when I Googled it just now it is actually called Electric Motor Secrets


    9 years ago on Introduction

    Is this design reversible? i.e. is it possible to build a Stirling engine that works the solenoid and creates enough juice to charge an AGM or other deep-cycle 12v battery? Thanks for your insight and ingenuity!

    Dr Qui
    Dr Qui

    Reply 9 years ago on Introduction

    No, a solenoid engine be used a s a generator.

    Mike McGill
    Mike McGill

    10 years ago on Step 14

    Having now taken the time to read the whole of your instructable, I now appreciate the neatness and quality of the design and craftsmanship.
    This Durafix aluminium welding rod is a new one on me. Can you buy it on the net ? And does it come with instructions ? I assume that a small blowlamp is sufficient to do the job - no oxy-acetylene ?
    Your Froment engine plans in the post today.
    All the best,


    Reply 9 years ago on Introduction

    I've used these aluminium welding/bronzing rods before ( i forget the name of the one i purchased, I bought mine off ebay from a seller with excellent ratings) Anyway my welds are still intact and solid. I used 2 standard plumbing torches to get the aluminium hot quick.

    Dr Qui
    Dr Qui

    Reply 9 years ago on Introduction

    If you use a stainless steel rod to stir the weld you get much more cleaner weld joints, clamping is the real secret. I have not used it much yet but have a use for it in some future project that are not far from starting.

    Durafix is impressive stuff but it does have its limitations, its almost worth it just to do the "fix the hole in the bottom of a coke can trick" as some people will almost bet money to say you cant do it.


    10 years ago on Introduction

    very nice finished project! i cant beat the sound of a mecanical electric motor!

    Dr Qui
    Dr Qui

    Reply 10 years ago on Introduction

    Oh there is one much sweeter sound buy far, the sound of a decent sized steam engine, the sweetest mechanical sound of all.


    10 years ago on Introduction

    I like the look of the final design and it's a great Instructible. However, why did you go to the complication of making the right angle linkage to the solenoid. Couldn't you have just mounted the solenoid vertically and eliminated the need for this?

    Dr Qui
    Dr Qui

    Reply 10 years ago on Introduction

    Well spotted,

    I only solenoid big enough for this project I had at hand was this flap type, They do not seam to be as powerful as the plunger type solenoids. This was on a phone exchange box an would have been 50V, it works well on 12v without overheating if left running for a long time. 

    I have made a plunger type solenoid before, but it was prone to overheating after a few minutes.

    Most designs for solenoid engines use the plunger type solenoids and have them mounted directly under the beam pulling directly down on each power stroke.

    I feared that the flap would be to heavy for the flywheel to lift if the flap was mounted in the horizontal position.

    With the flap mounted vertically all the weigh is carried on the pivot of the hinge and requires much less effort to return the flap to the open position.

    The overly complicated design of the linkage came about by me experimenting with the low temp aluminium welding rods to see what could be done with them.


    Reply 10 years ago on Introduction

    Thanks for your comprehensive reply. It was interesting to see why you made the design decisions you did. Good calls all round!

    Other options could have been to put a counterbalance weight on the solenoid flap or to have used a balance weight on the beam itself.

    Visually though, I think the right angle crank makes the whole design more mechanically attractive and interesting to look at.

    Nice job!

    Dr Qui
    Dr Qui

    Reply 10 years ago on Introduction

    The momentum in the flywheel is what pulls the solenoid flap back to the open position.  so you want beam etc to be as balanced as possible.

    Because the flap is almost vertical it requires the least energy to return it to the open position.

    If you imagine a plank lying flat on the ground and the force needed to lift  one end to the vertical position is much greater than the force needed to push a vertically standing plank over if pushed at the top.

    I agree with you that the more mechanical parts it has the more pleasing it looks, I guess it just gives you more to look at.


    10 years ago on Introduction

    "there where a few dead ends on some of the stages but then again certain failures led to better ideas."

    There is no such thing as failure in experimentation, only more data.

    Dr Qui
    Dr Qui

    Reply 10 years ago on Introduction

    True and also not true,

    The other ideas would have worked, they just would have looked like I had made them using my feet while working in the dark.  :-)

    Thats not a bad mantra though.


    10 years ago on Introduction

    Egyptians discovered electricity and created what's known coloquially as the "bahgdad battery" because of where some had been found. By using a canopic jar, copper rod, acids, iron and such, these old piles were used for electroplating and, I s**t you not, according to some ancient heiroglyphs, to either cure "impotence" or as a method of torture. Hard to tell exactly given the wires were just simply attached to the testicles in the pictures. Benjamin Franklin, who 70+ years earlier in his infamous kite and key experiment, already knew about electricity but wanted to prove that lightning was static electricity in the extreme. The leading wire from the kite, to the key had a second copper wire that went right into a dryden jar....

    Blah blah, you get the idea. We still use these on newspaper hopper lines, well pumps, saw mills and other useful modern contraptions.

    Let's see a bigger one on a model train. That would be an instant contest winner.