Jessica, aka My First Steam Engine

[Nerdz]

After much consideration, Ive decided to build my first steam engine instead of a stirling engine, based on the Advice of Others. The Name Jessica comes from the person who this will be given to for Christmas. I will be building a wobbler type steam engine

I also bought a book to help me in my endeavour, "Making simple model steam engines by stan bray"

We'll start this out by something I needed to make for my lathe, a carriage stop. It works, albit barely.

I got the cylinder made up, but its a bit oversized (0.433) vs the needed 0.375 for the wobbler engine. I could remake it, but I have another option; Bring it up to 0.500 by using whats known as a D-Bit (its a type of reamer using drill rod). Does it really matter if its a little bigger?

I also got the piston rod a bit too short, but I solution to this: Press fit on the "flat" end that connects to the cam. I also tapped it to 4-40, since I dont have a 5-40 tap

 

[Rivergypsy]

As a thought, I'd rather bore the cylinder than trust a D bit - you should get a much nicer finish, and also have more control on the size. You can always lap it to a finish afterwards too if you leave a little bit of material in there.

If the piston rod's too short, can you remake it or 'add' that material to the piston?

 

[Sshire]

My first engine (2 years ago) was from the very same book. It led me on a path to this engine building addiction.
Agree on the d-bit. Either bore or ream to dimension. Ideally, make the cylinder first and then turn the piston to fit.

One piece of advice which took me a bit of time to learn. It's frequently faster (and better) to remake a part than to try and "fix" it. I have a small box (getting larger) with incorrectly made parts, but every one of the dozen engines I've made was completed and runs.

My 2 cents.

 

[Nerdz]

I wanted to use a D-Bit because I dont have a set of reamers. I know, I know. I should have bought a set. I also dont have a boring bar small enough. I have a 1/4'' one from LMS, It did work, I had to set it high, but it still cut. I do however, Have some 1/4 drill rod. Ive made boring bars from 3/8's rod that worked perfectly. I could also just drill up to 3/8 and drill really slowly. There's ways around not having the proper tooling. Alternatively, I could just ask to borrow a 3/8 reamer from work.

I also realized I could make the crank pin out of steel, and then "flame color" it. I think it would be nice looking with a blue hue .

And yes, I could add material to the piston, but I could also add material to where the crank pin goes, or just remake it. Ive also thought of just leaving the 1/4 stock as is (which would probably be easiest) instead of turning down to 1/8.

 

[Nerdz]

Little bit of a update. I borrowed a reamer and proper drill from work. Told one of the machinists what I was doing (Im still learning) and he said to go slow, and use a lot of oil. Do it all in one shot. Once you hit the end, shut the lathe off and pull out (because a reamer might make it a little bigger if you go backwards with it on). Glad I did. 3/8 Rod fit Perfectly! In fact, when I pushed the rod in, I felt compression, and when I pulled it out it popped! Ive read that for stirlings, this is whats needed for a power piston. Even though its not a Stirling, It still gives me an Idea of whats needed .

I got the piston and the crank shaft done. I wanted to make it out of 304 Stainless. Remind me not to do that again! I abandoned it halfway though. It chewed up my HSS bit! I then did it out of Aluminium.

 

[Philjoe5]

304 stainless can be tough to machine, while 303 is fairly pleasant to work with.

I agree with Stan. Be careful of the changes you introduce into your work. Eventually you have to account for all of them and the more you have, the more difficult it is to factor them all in.

Good luck in your project

Cheers,
Phil

 

[owenlloyd]

Don't forget that a nice boring bar ( boring cutter ) can be ground from a piece of Cobalt HSS.
I've even re tasked a damaged solid carbide end mill (one flute had broken out) to boring bar duties ( just remember to use the correct stone for carbide grinding )
It is time well spent learning how to hand grind cutters.
Owen

 

[Nerdz]

I think Ive almost completed the engine. Ive got most of the round bits completed, with the exception of one bearing. Ive been taking hints and cue's from other engines, based on the time I have and incorporating them into mine to make it easier to build. Ive noticed that some other engines (like the Little Machine Shop Engine) Doesnt use a bearing. Makes me wonder if I need it..

Ive been thinking about how to make the intake/exhaust ports accurately on the engine. I saw one method that suggested to put the cylinder, crankshaft and crankpin together, and move it by hand. The Cylinder will then make a arc where the correct holes should be.

So that leads into my next question; How do I accurately lay out holes? I dont have a mill, just a drill press. I have center drills but I dont have machine length screw drills, just the long ones you get at home depot.

(More photos when I get home-It was a late night last night)

Addition: I managed to get the crankshaft and pin done last night. The only thing is the hole on the crankshaft that goes to the piston is a bit "off". I couldnt figure out how to drill on rod without having a mill. I did the best I could. I think the run out on my drill press is nuts :/ Im amazed at how quickly this is coming together. Tonight I'll do the brass bearing. It shouldnt take long.

ADD2: Yes the pivot pin is a 6-32 screw. I accidentally tapped all the way through. Theres only a slight leak around it, but I figured some loctite will secure it once I finally assemble it.

 

[Nerdz]

Well after a long vacation and coming out of a food coma, Its almost complete. I did mess up a little bit by screwing up the location of one of the holes. It needs to be moved or just made larger. Luckily it seems to be just enough off to give enough room for a 1/16th hole. I did venture out into the freezing cold and did a compression test. The piston spat out and I didnt hear any leaks. I thought the 6-32 screw would be a source for leaks, but it doesnt seem that way.

I also used a LOT of brasso and oil, chucked it up in a lathe and ran it at top speed to grind everything down a little. It has gotten smoother, but I'll have to repeat doing this. The piston doesnt "freewheel" on its own, it seems theres still some friction.

I just have to mount it and then its on to more advanced stuff, like a small boiler!

And yes, I did have to trim down the brass bearing to make it work with my hex cylinder, but I plan on chucking it up in the 4 jaw chuck and taking a little off to polish the sides.

 

[Nerdz]

Success! My First engine works! But its not over yet. I still have to make (or find) some kind of boiler. Ugh, why is copper so expensive! I had brought it to work and it ran quite nicely on 3psi. One of the younger machinists were there with me when I was playing with it (hes a few years younger than me) and seemed genuinely interested. We had gotten "adventurous" and turned the pressure all the way up (Shop pressure is 100PSI). My God, this thing screamed! I had to use force to hold it down. But I was happy that it ran on little pressure. I did try and see how slow I could get it. Seems these things have a minimum amount of pressure they need to work.

If I wasnt going to give this to someone as a gift, I would defiantly keep one around to "learn" on. See what effects what, like a larger flywheel, Larger Bore, etc. But hey, it didnt take long. I do plan on making another. All the math and physics in the world dont mean anything if I dont have something physical

As you can see I changed the main plate. Thats because I messed up on the original. Oh well!

 

[vederstein]

Congrats on your first runner!

 

[Nerdz]

This project is at a standstill. Im stuck. Its the last 10% and something has stopped me.I wanted this to have a boiler, so it could just run off of a candle (or something). I got 2'' copper pipe, but its just too big! Heres what other choices I have:

1'' Copper pipe from Homedepot (Those guys love me now that I have a home). I couldn’t figure out how to make the ends, so I bought a extra piece and made copper sheet out of it. Tried soldering it the best I can, but it didnt come out right.

A glass beaker, especially for boiling. I got this idea from a similar steam engine on (what else?) ebay. Borosilicate glass can stand the heat, and probably the pressure, after all, it moves on just 3psi. I havent had time to go to the local craft store to get corks. I have a semi empty bottle of Mead that calls my name once and a while, but I think the cork is too big.

Any thoughts on what I should do?

I also bought some awesome books. I managed to score a copy of one of Rudy Kouhoupt's books. I know the other two are probably overkill for model engines, But I'd like to know whats going on, and if possible, make my own (Plus Im a numbers sort of guy). I think he also has a few books on steam engines. I gotta get a hold of those.

 

[Swifty]

Chris, I've found it handy to "tin" the parts first individually, then put them together and heat up again. This way you know that the solder has reached the parts that they should, then you can trim the ends flush.

Paul.

 

[Nerdz]

Hello everyone! For the time being I have decided not to go with a boiler. I will save that for later experimentation. I doubt she would have run it much at all though . However, I did get around to using the boiler flask and it did create steam. The problem I had was pressure. If I pinched the tube, it built up enough pressure to, well, blow steam! So a valve or regulator would be needed for future prospects. Oh well.

So I went to the craft store and got some pre-made wood forms. I wanted to try something different and I thought that flame burning the wood would look really cool. If you ask me, it came out really nice and I havent even polyurethaned the wood! I cant remember what the technique is called. It just slipped out of my mind.

Paul, Thanks for the suggestion. I will give that a go .