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Thread: New Engine Build

  1. #1

    New Engine Build

    I figured with the vise finished, I would start on THE project, lol. Ive been planning on building a larger steam engine for quite some time, which since it's too cold/nasty out to work on tearing down the lathe to strip and paint it, I needed a new project, so here it is.

    Its going to be a 3" stroke, 3" bore steam engine, dual cylinder, and probably the base being made out of welded together C channel as just a small mill engine. All together, it should be around 2-2 1/2 feet long, and have a 10" flywheel. By my calculations, it should be around 5-6HP depending on the boiler I hook up to it, which is more than enough power for everything I could ever want to do with it. So far, Ive just gotten the cylinder pattern made for it, which I still need to build the corebox, steam chest, steam chest cover, and cylinder caps, but after the cylinder is done, the rest usually goes much faster.

    I could have gone with a custom designed frame and such, but due to my crucible not being big enough to pour enough metal for a full frame of the size of this engine, I opted to go with a design similar to a stuart victoria twin in the way that the piston is mounted to the frame. The rest of it will be different tho, and all of the parts will be custom made and cast out. I plan on using a displacement lubricator, which I already have a few brass round stock pieces that I was going to turn down and make it from.

    Here's pics of the cylinder pattern, all thats left to do with it is put a few coats of laquer on it to seal it up, then it'll be good to go. It looks all white colored because it's still covered in dust from sanding on it for the past day.

    Im not sure what kind of wood it's made out of, I just grabbed it off of the wood pile, (we use a woodburner for heat) and just turned it down.

    I discovered that I dont have a big enough bit to use as a core bit, so Ill have to go make one.
    Last edited by cae2100; 12-28-2016 at 03:00 AM.

  2. #2
    The only time You're not following your nose is when your going backward!.......Andy (ME) .
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  3. #3
    Well, at least the harddest part is over and done with, the other parts are pretty easy to make imo, and shouldnt take too much time to really build. I just cant wait till we have some decent weather again to start casting some of this stuff out when this is finally finished, lol. (getting anxious already, lol)

  4. #4
    Senior Member Tobho Mott's Avatar
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    Oct 2013
    Ottawa, Ontario, Canada
    Wow! What sort of work do you have in mind for your engine once it is completed? What type of metal is it going to be cast in? I can already tell I am going to enjoy following this thread.

    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

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  5. #5
    Im just making the parts and such in aluminum and steel where needed for now to work out all of the bugs with the patterns, then Ill send them off to be done in cast iron, or hopefully by then, Ill have the cupola finished and just pour the parts in iron from that. I have most of the parts for the cupola, just need to get some free time to assemble it and get it running. I calculated it out and a single cylinder is around 20ft/lb torque, which will be around 2-3 HP engine, and thats more than enought to run my lineshaft in my shop when the power goes out. I have a hit & miss engine coming sometime this summer to rebuild and restore, just need to go pick it up for that, but I figured a steam engine would be cooler and would make an awesome project, lol.

    I was mainly building it to take to various shows and such when it's done really. There's a few steam shows that I go to thoughout the year and wanted a stationary one to take to the shows, since most of what is around here is traction engines and steam locomotives that are running, not really any stationary engines tho. I keep changing my mind about what design Im going for, but eventually, I wanted to build a 2/3 size of an O&S horizontal engine, so I might just skip all the experimenting with the dual cylinder one and just build that one, lol. The amount of steam you need to run the dual cylinder one at the 3x3 is insane and I wouldnt be able to run it off of my boiler, but a single cylinder one should be able to run fairly easily. Im almost positive my boiler was rated for a 2 1/2-3 HP rating, so we'll see how it works out.

    Atm tho, I need a few drill bits of custom sizes to drill out the coreboxes, and dont feel like spending 20-25 dollars per bit bit, which will only get used one time, so Im just building my own bits, so until those are done, I cant actually cast it due to no corebox, also the weather is crap atm anyways,lol. Its mainly a summer casting project and Ill be working on this for probably the next year.
    Last edited by cae2100; 12-30-2016 at 11:21 PM.

  6. #6
    This is awesome, I can't wait to see it all come together! Quick question because i know nothing about steam engines, how do you calculate the power from the design? Is it just pressure and piston size or something?

  7. #7
    I forget the math and such involved atm, but I usually just base it off of the size of one that I know of for sure, which was a 5x5, which was 5-6hp one, but really it's mainly based off of the boilers and the pressures run through everything. The hotter and dryer the steam, the more power you can extract from it, and at those temps, the metals tend to be very wierd, but you can get a dual 3x4 compound steam engine, if you run the steam at so high of pressures and temperatures, you will get up to 120HP out of that one engine when it's running 600-800psi, it's mainly based off of the boiler pressures and temperatures of the steam coming out of them. I rated mine at around 2HP because of just being made of aluminum, I dont want it to have super high temps which would warp/distort/soften the cylinder walls and such, I just plan on having it running a lower pressure of steam also, maybe 20-30 psi. Different engines are designed with thicker walls and such to handle the higher pressures, so it would mainly be based off of that also in the design. Im going with 3/8-1/2" thick walls on the cylinder walls, but like I said, Im only going 20-30 psi max, and some of the time, Ill just be running it on air anyhow just to play with it, lol.

    The higher the steam temperatures and such, the more the steam is expanded, so it's much more effecient and uses less water to run the engine longer. For comparison for steam engines, I believe most locomotives ran at 100-250 psi, most toy engines run on 2-10 psi, and stationary engines will go 30-80 psi depending on the applications most of the time.

    Ive repaired quite a few engines, but never actually had one of my own to really tinker with, and was wanting to try to create one completely from scratch, thats why I was wanting to try doing this, lol.
    Last edited by cae2100; 12-31-2016 at 05:00 AM.

  8. #8
    Well, I figured I'd update this, I would have done it sooner but been working like crazy trying to do up the patterns needed, and finally got some time to myself, so been going nuts on them. I have the steam chest, cover, cylinder covers, cylinder, and two forms for making the corebox. When I made my cylinder pattern, I didnt realize it but the wood had actually expanded and the core prints went from 2 3/4 to 2 7/8, so have to make a corebox to compensate for that little hiccup. I just turned two 2x4 pieces of lumber to make corebox prints since I will probably only need to use them once really, and I plan on making the actual corebox from plaster of paris as soon as I make a box frame for it. I may cast it in aluminum just to make a permanent corebox that will last much longer, but we'll see how it all goes, lol.


    Everything has gotten a few coats of polyurethane, which now they look and feel like they have a coating of glass that should pull from the sand very easily and seals everything up to make it waterproof.


    I keep looking at designs of engines and the plans that I had before, I realized that there were little bits here and there that just annoyed me or didnt look right, so I finally just decided to design my own for the base, lol. I am taking everything that I like from all of them that I worked on in the past and pics of model ones that Ive seen, and combining everything together to make one that is going to hopefully look good, lol. I also was thinking about it and dont really care for the standard governor setup, and was going to redesign that with dual eccentrics so that the idle can be set easily, and the governor will use those to adjust the valve timing to increase effeciency rather than using a valve under high pressures to control the steam. It gives a little more power when it's really bogged down when you really need it.

    Also, dont mind the stuff written on it, I tend to do that with a sharpie to read out dimensions for things Im thinking of since it doesnt really affect the cast finish anyhow, just odd dimensions for things like steam chest dimensions and such, lol.

    The body of the engine is next to come after the corebox, but I think I must be the only person in history that doesnt have vasoline at home, lol, so trying to find a replacement release agent to use on the corebox halves, then after that, it should be ready for a flywheel design too. I was looking at just casting one out, but not sure if I can get enough zamak for one, and I cant turn it on my lathe, so might just have to buy one unfortunately. I was going for a 12 inch flywheel, but my lathe can only support stuff up to 9 inch, non split bed.

    Thats all for now, and I would have uploaded pics sooner, but the phone battery kinda went dead because someone forgot to turn it back off after taking pics last time or plug it in... *whistles*
    Last edited by cae2100; 01-03-2017 at 05:08 PM.

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