Steam engine for a sternwheeler

[apointofview]

Next I remade the levers for the valves. I didnt like the look of the first levers so after some doodling on paper this is what I came up with.


The next items to build were the cams. The shape is very different from most cams. It opens the valves very fast and keeps them open for most of the stroke. The full scale engines ran cams like the one I made and then used a cutoff mechanism to stop the flow of steam to the cylinder mid stroke when less power was needed and to improve efficiency. I may add a cutoff some day but that remains to be seen.


It took awhile to figure out how I was going to fabricate the cams, but eventually I came up with a jig that gave me two pivot points on my rotary table that allowed me to cut the curves I needed. I had to mark several points on the metal to start and stop cuts and then rotated the part and the table multiple times to get it all done.

There was a lot of force needed to turn the cam aginst the valve springs once it was installed. That force made for a bunch of friction, I had to wrap the cam with teflon to get the friction low enough to allow for the engine to turn slow and smooth.

Pete

 

[Philjoe5]

I really enjoy your posts. The photo documentation is excellent. I can appreciate your having to stop in the middle of a machining operation to take a picture

Cheers,
Phil

 

[Herbiev]

I was about to say exactly what Phil said. Great work.

 

[motoseeya]

man I hope to one day be able to come close to the kind of work you are doing. looking forword to seeing more of the build.

 

[apointofview]

Thanks guys ! It is very hard to remember the camera. It has to be sitting right next to the machines or I will skip shooting the part so I can keep my train of thought going. What has helped is there have been multiple parts that are all the same so the pictures are usually not of the first one. Shooting the copies is easier because I am just repeating what I did and not having to figure much out.

As far as quality goes thanks a bunch, but I am just a hack and I am slow. My boiler was the first part of this adventure and it was started back in 2010 !! I have been working on and off on this since then. I have modified so many intended dimensions due to goofs in this project. What helps is that there aren’t any plans so you couldn’t prove the discrepancies !! If I had some formal training on machining then maybe I could take on something like the gas burning mechanical wonders I see others create. I sure couldn’t do what I have done without this web site. I have seen so many fantastic projects built here and all the advise that is freely given is amazing.

Supports for the cross shaft for the valve pushrods were next. Pretty simple I just hacked them out with a ziz wheel and then cleaned up the edges with the mill. I just had to keep repositioning the parts to cut straight lines due to the lack of cnc ! The brass ‘bushing’ got dressed up a little by removing material in the middle. I also had to remove material from the beams that support the engine to allow the supports to sit flush but no shots of that today. I didn’t get pictures of making the little fittings that make up the rod ends and levers, so just a shot of them completed and installed is all I can offer.

Almost caught up to where I am in the build process
Pete

 

[apointofview]

Next up, the cranks for the paddle shaft.
I had made temporary parts out of wood for the test run, so I already had the critical dimensions needed. I spent most of the time getting the rotary table setup correct. It is always tough to switch out the vise with the RT. I try to avoid switching too much but it seems I have the wrong one mounted most of the time. Anyway it was just a matter of drilling the holes and then I used a ½ inch shaft in the 4 jaw on the RT to provide support. I used the set screw that will secure the crank to the paddle shaft to hold the raw part to the shaft in the chuck. The smaller bore end I had to drill the support shaft and bolt down the part since there isn’t a set screw to use. I pressed a brass pin in the smaller bore for the connecting rod to ride on later.
Pete

 

[apointofview]

Next to build were the connecting rods.
I had the quick test run rods so all I needed was to make nicer looking permanent versions. I made the ends out of aluminum and the beam out of poplar. I made a full size doodle of what I wanted it to look like and then started with the ends. The pics are of the engine side fittings, the other ends were made in a similar way. All the work was done on my mill with my rotary table. I stained and coated them with polyurethane to make them water proof.
Pete

 

[barnesrickw]

Beautiful done with the mix of metal and wood.

 

[apointofview]

Thanks for the complement!

Ok I need to fabricate a bunch of items to get this engine running on steam. I decided to get the lubricators done next. I did a lot of reading on the internet and decided on a dead leg displacement oil lubricator to do the job. I made two one for each cylinder, and I will position them just before each engine.
I made a drain valve on each one to remove the water that accumulates based on a design I saw here - http://www.nelsonslocomotive.com/Shay/Engine/CylinderCocks/CylinderCocks.htm

I tried to make tapered drain cocks with little success. They kept leaking !! I found this design with a pin rotating in a Teflon sleeve. It is simple to make and works great.
I made an o ring sealed cap and threaded boss to hold it and then soldered it all together on a 1/2inch pipe. Last was to drill a small hole in the feed line and into the side of the assembly and solder that all together.

It will take two posts for all the pictures.

Pete

 

[apointofview]

Not the smoothest sequence of pictures but hopefully you get the idea !
Here is the rest
Pete

 

[don-tucker]

Beautiful work,exactly how I go about things.love the fact that it is all done manually as model engineering should be 😜
Don


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[apointofview]

Thanks Don !!
I wanted to try my hand at making a couple of ‘T’ fittings to attach the new lubricators to the engines. I know I could just solder the plumbing together but this was fun to try.
I am running 1/4 OD copper tubing for the steam lines and all I have available is ½ 360 brass stock so it made for one leg being small but workable. After I whittled it down with the lathe and mill I ran my dremel across it for awhile and then hand filing. A final sanding and polishing made for a pretty good looking part.
The funny thing is all that cleanup effort was really for practice only, because I wrapped the steam lines with cotton string to insulate them ! Didn’t think that far ahead!!
Pete

 

[Heffalump]

Those T's look great!!!

 

[apointofview]

Thanks for the kind words !!

Ok next on my list is throttle control. I made a throttle way back before I started the engines and it proved to be more of an on off switch. I did a lot of searching for ideas I could build and I found this http://www.homemodelenginemachinist.com/f12/rotary-steam-regulator-9492/ on the downloads section of HMEM ! Thanks Adrian !!! It is a neat design and so far works great on air !!

I changed it a little to suit my materials. I started with an old piece of 3/4 brass drift and made the body.




I’m still not sure how to single point thread clear to the base of an object but I got close. I ground off the side of my tool bit to do it. If there is a better way I would love to hear it !




I kept the base and the top of the regulator together for the bolt hole drilling operation so they would line up to each other. So it was over to the rotary table on the mill for those. I used 2-56 stainless cap screws here.





Back to the lathe to part them and then face the base as smooth as I could. The critical part of this valve seems to be the finish of the valve disk and the base.






I thought I got them smooth but the camera tells me I still have a little way to go. Some of the marks on the brass are left over polishing compound. Its getting shinny, that dark circle in the middle is the reflection of the camera lens !



The top of the valve went in the lathe to make the cavity the valve disk sits in. I used an end mill to start the hole and a boring bar to get it to size.




More valve parts to come in the next post. I am out of room for pictures.

Pete

 

[apointofview]

The stem and plate that has the driving pins was my next task. I drilled the center of an old brass faucet stem.



Moved it to the mill where I removed the sides and drilled the offset holes that the design calls for.




back to the lathe to part it off and then press on the stainless stem and thread in the 2-56 studs. silver solder it all together and done with that piece.






The valve disk is next, the same faucet stem made for a perfect size to start with. I made the face as smooth as I could



over to the mill to cut down one side. here I changed the design to cover the hole in the base easier and allow me have a larger hole if I need it. Then back to the lathe to cut it off.




I needed to drill the two small pockets that the studs sit in and not ruin the smooth surface on the other side. I came up with super gluing the disk to a hunk of aluminum and then clamp it up to do the drilling. It worked well and the super glue came off easy from the shiny brass surface.



This is the assembled top



Not enough room to show the drilling of the top and bottom parts for the inlet and outlet, but it was just some careful lining up and one shallow hole in the top part. A little copper tubing and some solder and its done.



The bottom had another change, I made the base thicker to just let me drill the steam passage across the middle of the base to eliminate the work to make plumbing parts the plans show. I also moved the outlet hole to the side near the inlet hole because my half circle disk would restrict steam flow. As it is there is almost a straight shot from the inlet hole to the outlet hole when full open.



The only part I didnt make was the gland nut. Those are from the plumbing section of home depot. All I did was drill a hole for the stem and cleaned off some of the nut faces to dress them up. I bought those because I dont know how to make internal threads that go to the bottom of the part. At .60 cents its not that big of an expense !



All done with both, I just need to make flanges to make it so I can bolt them in the system.



Pete

 

[apointofview]

I gave the engines a short test run on steam, and I found out things are much different than nice clean compressed air !

Condensation is going to be my biggest problem I think. I had lots of water blowing out of the exhaust pipes and since they point up I had big slugs of hot water burping out all over.

This little trial run made me work on a cylinder drain setup. because the bottoms of the engines are not easy to get to I wanted something that would stick out the front of the engine and need only one point on each engine to open and close them. I didn't want to have to rig up a way to move four separate independent valves all at the same time.

After much head scratching and staring at the engines this is the solution I came up with

Started out with brass and turned it down in order to thread it to 10-32


Threaded it with a 10-32 die and drilled out the center with a nbr 40 bit


Over to the mill to drill out the passage for a teflon sleeve and cut it down a little to allow a wrench to tighten the fitting.




Parted that off and made three more




Next was to drill, tap, and spot face the cylinder ends for the fittings. The spot face was a little different on each of the four cylinder ends to allow each fitting to line up correctly. That made it so I have to keep the same fitting with its matched cylinder end.




I made the four Teflon sleeves next and inserted them in the brass fittings.




I had to modify the brass end covers to allow for water and steam to be able to get to the hole in bottom of the cylinder end fitting. This is the inside surface of the flat cover the other end that has the piston rod is similar.



I dont have enough pictures to show everything but here is the bottom of one engine and I will try to explain whats going on. The 1/8 brass pipe that runs through the two drain fittings has a brass plug inside it halfway down its length. There are two small holes drilled in the pipe both in the same direction at the center point of each fitting. By rotating the pipe I can line up the holes in the pipe to the holes in the cylinder drain fittings which allows water and steam to escape. The plug in the center of the pipe forces all that to go to the open end of the pipe and overboard out of the engine. If I didnt have the plug installed the some water would just go from one end of the engine to the other.




I made a few levers to clamp for my throttles and for the cylinder drains. Later I will connect a push rod to both levers so one movement will open or close all 4 drains. Seems to work good on air.



Steam will have to wait because I still need feed water pumps ( I run low on water to fast ) and some more insulation to try to keep the heat in the steam. There is sure to be more stuff I need to make that I haven't even thought of yet.

This sure is a long term project !!!

Pete

 

[apointofview]

I ran it on steam !!!

I have been working on plumbing in the engines to run off the boiler I made several years ago. It was late at night and I had to work in the morning ( 3:30 am wake up ) but I couldnt just leave it all hooked up and not try running it. So after oiling up and filling the boiler with rainwater I have been collecting, here is what it looked like !!

[ame="http://youtu.be/W6c2ZtJiy0w"]http://youtu.be/W6c2ZtJiy0w[/ame]

This is another view


http://youtu.be/sTV-OIMf2jw


Sorry the video is so wobbly but I was in a hurry so I could keep up with the water level and pressure. I'll do a better one later and maybe I will clean up the area a bit to see everything easier !!

I am pretty thrilled !! I have been thinking about this event for a long long time.

I still have lots to do. The throttles failed, I think the solder joint inside gave out so I have to redesign those or use real silver solder. ( I ran out and was avoiding forking over for more ) There are several little leaks to fix and I have to hook up the axle water feed pump to keep up with water consumption. Also it looks like the boiler will need more heat. All I could maintain was 20 psi with the engines unloaded and that was not for a long time. I think its a little small for the job but its all I have and building another is not an option right now.

Anyway did I say I was thrilled !!!! I didnt even get to bed till 12:00 and then I couldnt sleep. I maybe slept 2 hrs but it was worth it !!!!!!

Pete

 

[doubletop]

Pete

Looks like I can be the first to say congratulations.

First time on steam is always a major moment, and a must in my book. Running on air is only half the job.

Pete

 

[apointofview]

Pete,

Thanks a lot!
I had no idea how much more work steam would be vs the trusty compressor. It sure is messy too. There is still a lot for me to figure out to get it running for any length of time and doing it slow and steady. I sure am having fun learning though.

I do have a question for you guys with more experience (which is probably everyone ) How much steam oil should the engine be using for a run. I ran about a quart of water thru the boiler in addition to the water that it was filled with initially and my oilers levels only dropped about a quarter inch. That doesn’t seem like enough, but I'm not sure how to tell what is the right amount of consumption (each cylinder has its own oiler and they have a diameter of 1/2 inch.)

Thanks
Pete

 

[Jyman]

That sounds a little heavy on the oil, as steam does also act as a lube when it condenses in the cylinder. You should be able to get away with using about half the oil that you are using. I would open up the engine and look for any piston marks on the cylinder. As that is a good way to tell how much oil you need.

But that is totally up to you, on how you feel about how much oil you are using. You are the one running the engine not me.


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