My first steam engine

[savarin]

I'm starting to build a small steam engine of sorts of my own design. Hopefully a double acting uniflow design.
I dont have any drawings because I'm working it out as I go along using what I have available .(and Stealing ideas from everywhere). Its just a learning exercise to see if I can and time is not really a problem. A lot of the fun is in working it out.
The idea first came about as I was playing around turning some galvanised water pipe then boring it out for as long as I could. The surface finish both inside and out was way better than I expected and my first thought was "this could be the cylinder for a steam engine.
So the next bit of playing was to see if I could mount a 1" square piece of bar and cut a curved surface along its length.

I used the vertical slide I built to make the gear for my reverse tumbler and two small "G" clamps that I cut the screw threads off and filed a 4 flats in the end to tighten them with. (not a lot of room ) I made a couple of passes to set it all up and shimmed the block to get the cut square.

It worked and the surface finish feels smoother than it looks. I dont think I ground the bit to a good profile for this job.


But the end fit looks good to me.
I find it almost impossible to believe it actually worked.

Now I need to stick the block (eventually the valve block/steam chest) to the cylinder.
So the first question is will braze flow through the whole join or will I have to use a softer silver solder.
Thanks.

 

[lotechman]

Generally brazing alloys will not flow into gaps less than 1/16th. Silver solder ( actually silver brazing alloy ) will flow into gaps only a few thousandths.
Any alloy will not flow until the base material is up to temperature meaning that the whole assembly has to reach brazing temp to get good flow.

 

[savarin]

Generally brazing alloys will not flow into gaps less than 1/16th. Silver solder ( actually silver brazing alloy ) will flow into gaps only a few thousandths.
Any alloy will not flow until the base material is up to temperature meaning that the whole assembly has to reach brazing temp to get good flow.

Thanks, I was unsure regarding the braze so silver brazing alloy it will be.
Temp wont be a problem I have 2 home made propane burners, one from the furnace and another for a more concentrated heat.
I'm still tossing the standard double acting or the uniflow around and cant make up my mind.
Gues I will have to make both, damn.:rofl:

 

[Terrywerm]

Nice job!

Ditto on the silver solder, it should do the job you need.

Keep us updated as your project moves forward. I for one am quite interested.

 

[Dataporter]

Get some of the silver solder that is a thin thin ribbon. Gunsmiths use it, I think it is .005 x 1/2". put some appropriate flux on it and lay the pieces of ribbon between the two parts like a piece of thin sliced cheese between two pieces of bread. Heat the whole thing up like you would a grill cheese sandwich! Voila! No Gaps.

 

[12bolts]

Thats neat work Charles,
I going to be watching this one.

Cheers Phil

 

[savarin]

Thats neat work Charles,
I going to be watching this one.

Cheers Phil

Thanks Phil,
the current experiment will dictate whether it will be a standard or uniflow engine.
I really must get a real 4 jaw chuck, I just took a skim of the jaws face and they were different by approx 0.5mm, no wonder I couldnt use them as a back plane to butt the plate to.
A chunk of plate, faced, bored to fit the outside of the cylinder, then the inside face of the circle turned to make a "U" shape inside if that makes sense.
I havnt quite worked this one out yet but I'm hoping I can grind a bit of tool steel to a profile either on the side of the bit or a small one to place in my boring bar.
This will hopefully be the exhaust manifold.
ps, how was the glass?

 

[savarin]

Looks as if the uni flow is on the cards
I bored out a chunk or 3/8 plate to fit the outside of the cylinder and used a small ground bit of HSS to cut the inside groove.
To turn the outside from the rough cut plate I mounted it on a mandrel.


This is the finished manifold that will be silversoldered over the ring of exhaust ports



That have not been drilled yet.



I'm considering drilling them at an angle so the steam swirls into the manifold rather than at 90'.
And maybe cut into the middle of the manifold with a hacksaw (no mill) and file so a copper pipe can be again soldered in between the two flanges giving the maximum amount of egress area.

 

[savarin]

I used to be indecisive but not I'm not too sure.
I've cut the steam egress point in the manifold but I'm in two minds which way to go now.


As there will be quite a few silver soldering operations on the cylinder and even though I'm used to multi operations on the same piece with different melting point solders I'm considering tig welding the steam collection chest to the manifold to reduce this number.
Anyone think of a reason not to?

 

[savarin]

Made the manifold ring


drilled the exhaust ports and made the collector which I welded to the manifold


It will sit over the ports like so.
The small hole is only a pilot hole for when I make the joiner for the pipe work.



I havnt quite worked out how I'm going to make the steam valve and chest yet so now its the turn of the crank shaft. That should be quite an exercise.