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gizmo2
10-01-2011, 03:25 PM
http://i1217.photobucket.com/albums/dd398/kblaneywyo/steamtoyflywheel003.jpg

This was last winter's project, a steam drill from the 1880's. I knew nothing about steam or working with cast iron when I started, so it proved to be quite challenging. I think I stared at the prints three days before I attempted any machining.

I think the hardest thing to figure out (for me) was the fact that everything is oversized, tapered to pour correctly without voids, and pretty gnarly for starters. What do you use as a reference? Where is the center line? I made and chased mistakes on nearly every part. Remarkably, it runs quite well.

My next one will be better; I'm thinking about the vertical coke bottle next.

DFMiller
10-01-2011, 03:34 PM
That's very nice.
I have a couple of casting sets but still have not got past the issues you speak of. If you have any pictures of some of your set ups etc on how you got over the issue of turnings casting into machined parts would be appreciated.

Thanks
Dave

sasquatch
10-01-2011, 06:36 PM
Gizmo, Impressive little machine, very nice and great striping on the flywheel.

brian Rupnow
10-01-2011, 06:49 PM
Nice stuff!! I started building model steam engines about 4 years ago and have enjoyed the hobby very much.---Brian

laddy
10-01-2011, 07:17 PM
Looks Great! Does it run???

gizmo2
10-01-2011, 08:09 PM
Yes, Laddy, it runs. I've never had it steamed up, but it runs great on compressed air, down lower than my dial reads. Mr. Miller, I'm hardly the one to give advice, but maybe I can get you started. This model has a 1 inch bore with a two inch stroke. The casting was less than 3/4" ID as received.

I made a mandrel 3/4" OD with centers. With a rat tail file, I opened up the bore of the cylinder until that mandrel could just slip in with some resistance. With the cylinder along for the ride, the side that will bolt to the frame outboard, mount it between centers. Now you just have to secure that cylinder somehow, slide out the mandrel, and bore it to spec. Also face and OD turn that end of the casting at this time.

With a new mandrel that fits the new bore, you now have your centerline for your model. I reamed a 3/16" hole through this new mandrel, and used a drill rod as the center punch/reference for futher operations.

DATo
10-02-2011, 06:23 AM
Nice job gizmo2 !

This is one I made over a long period of time at work. Whenever we were slow the boss didn't want us to look idle so he let us work on G jobs. I'd put in an hour here, a half hour there and in time I got it done. Not nearly as nice as yours though gizmo.

http://i1189.photobucket.com/albums/z430/D-D-DATonian/SE.jpg

It is a three cylinder radial engine with a total of 1.5" bore. The offset crank causes the fork-like valve rockers to actuate from side to side as it rotates (the crank pin slides along the slot in the forks) There is a small hole in the top of each cylinder where the hoses connect and as the valve top slides from left to right air is pumped either into the hole or exhausted out of the hole (the right side of the manifold is intake and the left is exhaust). So as the thing is working one cylinder is always on intake, another on exhaust and the third somewhere in the middle. Put-puts like a champ on compressed air. I usually keep it at work to demonstrate to the kids of employees when their parents bring them in to show them our shop. EDIT: Forgot to mention ... there is a connecting rod running from each of the pistons to the same shaft (crank) that the forks slide on. As the pistons are driven upward and downward they push the shaft radially which in turn causes the valves to actuate as both actions are of course common to the same crank shaft.

gizmo2
10-02-2011, 10:28 AM
dato, those radials are really fun to watch run. We're just across the street from the Union Pacific rail yard in Cheyenne, where they stable and maintain the steam trains. Those guys come in the shop often, and get a big kick out of the toy.