Steam Engine for Meccano

[John]

I wanted to build a steam engine I could bolt into the 'guts ' of a Meccano model. The boiler will be separate and connected to the engine by some soft copper tubing suitably lagged just like the real thing. Using all Meccano compatable parts will let me assemble the engine in different configurations to suit the need.

This is a 'back of an envelope' sketch of what I have in mind. (In fact it is the working drawings - altho I did some more on graph paper to get the scale right)

Ok so thats the idea. The whole thing is built on a Meccano U channel but could be any part of a model The crankshaft is a Meccano axle so I can fit gears and sprockets straight on it. I can even even bolt the cylinder on the other side of the U channel if needed. The flywheel can go outside the channel as shown or inside. All very flexible.

I started by cutting the brass plate bits on a $49.95 scroll saw fitted with a cut down junior hacksaw blade. Works great but gets thru a few blades -but they are cheap.

Also cut some tube for the cylinder and the crank for the crankshaft. Turned up a plug/cylinder head from bar stock.
This is how it all looks so far.

Started on the piston. Drilling the hole to fit the conrod.

Parting off the piston. Made a couple of oil grooves to help with lubrication.

Here is the finished cylinder and piston.

Turned up a boss for the crank to fit Meccano axle. Used a steel bolt for the crank pin. Soldered the boss to the crank and drilled through.

So here we are after a few hours work.

Now have to find some brass scrap for the flywheel and the valve block.

Off to the crap metal dealers again.




John

 

[Powder keg]

Looks like a fun little engine. I can't wait to see the finished product.

Wes

 

[lugnut]

John that looks like a fun project keep us informed on the progress.
Mel

 

[tmuir]

Looking good so far, keep the pictures coming.
I'm especially interested to see what equipment your using as I will be tooling up soon but have a limitted budget so its always good to see what other people use to help me make an informed choice.

 

[Bogstandard]

Now your getting round to it John.
Begin simple and progress from there, you will soon be up with the best of us.
Its nice to see you have made some basic plans as well.
Well done.
They're not bits of six inch rules your using for shims are they? Steel and ally tin cans work rather well when just starting out. But you can use vernier calipers for shims, if you can afford it.


John

 

[John]

You mean the shims under the lathe tools? They are feeler gauges - cheap ones from the local car parts emporium -about $5 a set. Just the thing to get the tool to the right height as you can use two or three in combination.

Had a win at a local scrap yard. Picked up a nice lot of brass off-cuts including a 1 1/2" diameter length of brass stock- enough to make many flywheels. Also a nice piece of seamless brass tube 2" diam and 3/64" wall thickness. Just right for a boiler. 5 Kg all together for $20. Really pleased with all that.

Will be away for a week so there will be a pause in the postings.

Thanks for the encouragement guys.

John

 

[John]

Back in the workshop after a weeks break.

Manufactured the sliding valve plate and used it to mark out the holes for the inlet and exhaust ports. A bit fiddly but worked it out in the end.

Here is a picture of the sliding plate set up with the cylinder ready to solder the two together.

Assembled the engine and found that the con rod was about 3mm too long and the piston covered the inlet port at TDC. Unsoldered the big end bearing and shortened the con rod. Had not put the cylinder head on yet so could see how it all fitted.

Finally all seemed OK so here is the engine so far assembled. Need to clean up those solder fillets!

Now need to turn up a flywheel and then try a test run on compressed air. The flywheel will be a 'Fat Boy' less than 1 1/2" diameter as I want it to fit inside or outside the Meccano channel.

Here is the start of the flywheel.

More action to follow!

John

 

[John]

Turned up a flywheel and assembled the engine. Does it run? It sure does. Just blowing down the tube turns it over but you soon run out of puff. Connected to my 12v car tyre inflater it goes like a ripper. Sorry I don't have video.

Vibration is a bit of a problen but what can you expect from a single cylinder, single acting engine. Lots of torque especialy with a bit of gearing as shown.

What would I do different? I think I may rebuild it in a little more compact fashion. Shorten the crank throw to reduce the stroke which would allow a shorter cylinder, conrod and backing plate.

Maybe also build a 'mirror image' cylinder etc. to go on the other side to make a twin cylinder engine which should reduce the vibration.

May also have to make up some proper bearings. The Meccano idea of just putting an axle through a plate soon makes grooves in the axle if there is significant loading or speed.

All in all a fun little engine and my first runner!

John

 

[wareagle]

That is a fine little engine! Looks like a fun and simple build. May have to put that one in the que myself!

Nice work!

 

[Bogstandard]

John,
Very well done.
It must have boosted your confidence now the first one is built and running, and given you a good smile.
Progress gently but steadily and you will soon be banging them out.

John