Author Topic: AOGís version of the Stuart S50 Engine  (Read 4150 times)

Offline Ye-Ole Steam Dude

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Re: AOGís version of the Stuart S50 Engine
« Reply #30 on: December 15, 2018, 10:05:14 PM »
Hello Tony,

Very good progress pictures on this build.

Have a great day,
Thomas

Offline bent

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Re: AOGís version of the Stuart S50 Engine
« Reply #31 on: December 17, 2018, 08:12:47 PM »
Looking good, Tony!

Online AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #32 on: December 18, 2018, 04:13:26 AM »
Thanks everyone, I think itís time to close this one out. The next part made was the flywheel. Yet again I had a cast iron part that belongs on an artillery shell instead of an engine. This time I was at least able to get a usable part out of it. I started by trying to file off the flashing to get the casting semi presentable. The flashing was so hard I had to use a rasp to do the filing. My regular machine files were skating right over it. The good news is that other then some flashing on the spokes, the rest of the casting was in very good shape. The next thing I did was to clean up one side of the hub using a bump center to get it running as true as possible.



Then the part was flipped and the other center cleaned up and drilled.



Next I loctited the flywheel onto a mandrill for turning between centers. After the Loctite cured, I tried to face the front of the rim with no luck. I ended up breaking an insert trying. The same thing happened with the other face. Thankfully they werenít to bad so I just touched them up with my rasp. With those done I was able to break through the hardened outer layer on the outer circumference and get that to dimension. When you look at the picture you can see how thick the shiny (hard) areas are on the faces.



With that done, I heated up the mandrill and removed it from the flywheel. The last thing to do on the flywheel was to drill and tap the hub for a setscrew.



Needless to say Iíll be painting this flywheel. With that done I made the valve and piston nuts. They were both made the same way so Iíll only show one. First the outer diameter was turned for threading.



Then the thread was cut and the center drilled.



The nuts were parted off and cleaned up. The last part to make was the crank pin. The instructions call for you to make a slotted steel screw but since Iím not a fan of slotted screws and I have already fabricated a bunch of other things in this engine I decided to change it up. I had a scrap of the 5 BA hex stock that the piston nut was made from. I turned it to shape, threaded the end and parted it off.



With that done I grabbed a scrap of Corian and made a base. With the exception of the connecting rod (which still needs rounding over) that completes the metal work on this project. Itís time to pull it all apart and paint it. Here is a final family shot.



Till next time

Tony


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Offline bent

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Re: AOGís version of the Stuart S50 Engine
« Reply #33 on: December 18, 2018, 05:30:39 PM »
I have to agree with you on slotted screws, Tony.  Bugger about the flywheel, but luckily the hub wasn't as bad as the rim?  Did you consider trying to anneal it?

Offline Gas_mantle

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Re: AOGís version of the Stuart S50 Engine
« Reply #34 on: December 18, 2018, 05:54:35 PM »
I look forward to seeing it running  :)

Online AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #35 on: December 18, 2018, 07:00:49 PM »
Did you consider trying to anneal it?

Thatís the problem I need to get to grips with. A I have no idea how to do that with cast iron. B I donít have anything that will get hotter than my oven that would be able to evenly heat the parts.. These are on my list of things to work on after I get this thing running.

Tony

Online AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #36 on: December 27, 2018, 08:06:52 PM »

Offline ettingtonliam

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Re: AOGís version of the Stuart S50 Engine
« Reply #37 on: December 28, 2018, 05:02:25 PM »
Forget inserts. Find a good quality (NOT Chinese) brazed tip carbide tool, round nose for preference, cutting speed no more than 50 feet per minute, so 50 rpm for a 4" flywheel, and a decent cut to get under the skin first go. HSS would do it but carbide is better. Taking a light cut and letting the tool rub on the skin is a guaranteed way to knock the edge off the tool.

Annealing cast iron is easy if you have an old fashioned open fire or stove. Get it good and hot, shove the casting into the glowing coals and leave it there overnight until everything is cold. The oven just won't do. Thats the trouble with small thin castings, they loose heat quickly in the foundry, and are prone to chilling, but its disappointing that Stuarts can't do better. They've made thousands of S50s over the years and used to have a reputation for good quality castings. Have you complained to them about it? I know I would have done by now.

Online gary.a.ayres

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Re: AOGís version of the Stuart S50 Engine
« Reply #38 on: February 12, 2019, 12:51:18 AM »
Interesting build log showing a great deal of skill on your part which you use to good effect in finding workarounds for some of the issues which arose.

I guess I have all of these kinds of challenges to look forward to in the future!

Online AOG

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Re: AOGís version of the Stuart S50 Engine
« Reply #39 on: February 12, 2019, 01:24:32 AM »
Thanks, but Iím not sure I would call it skill yet. I feel like I am just past the beginner phase of my model engineering journey. I feel reasonably comfortable with the basics but I am still striving to improve my execution. These casting sets and the issues that come with them are just another set of skills to be mastered. I will make more of these S50s until I make one that meets my standards.

Tony