3D Bottle Engine

[JorgensenSteam]

I am making some progress on the 3D modeling front, although I still have a long way to go as far as being proficient at modeling/assembly/drawings for 3D.

Inspired by the Welch Lawson, I am going to try to build a bottle steam engine.



Pat J

 

[Heatherrose]

Very interesting design. I look forward to following your progress.


​

 

[tel]

Keep us in the loop Pat, the bottle engine is one I've always wanted to do!

 

[JorgensenSteam]

I have kicked the idea of a bottle engine around for about five years now, and had a few ideas about how to build it, but having ideas, and actually having ideas that work as far as machining are two entirely different things.

I decided to try a small prototype using a piece of 2 inch brass, about 5.5 inches long. The turning went ok, but brass is terrible about snagging when you drill it, so my cutouts in the frame are not right.

Having seen the Welch and Lawson engine, I decided to try a slightly different approach using stacked steel disks so that I could turn the interior, and avoid having welds on the interior of the frame.

The steel frame is about 8 inches tall, and 4 inches diameter.

I would really prefer a 9.5" height and a 5" diameter frame, but 4" was the material I had on hand.

Here is the first attempt using brass.

 

[JorgensenSteam]

Here is the taller frame in steel with a bored interior.
You really have to clamp the disks to keep them from shifting during welding.

 

[JorgensenSteam]

More steel frame.

 

[JorgensenSteam]

Steel frame construction.

 

[JorgensenSteam]

Steel frame.

 

[JorgensenSteam]

Steel frame.

 

[JorgensenSteam]

steel frame

 

[JorgensenSteam]

And here is the base, and a comparision of the sizes of the brass and steel frames.
I will add a temporary base on the top so that I can clamp the frame to the mill and mill out the sides.

 

[JorgensenSteam]

And here are a couple of "go-by" engines, the frame being like the one shown in the public domain book by Scranton.

I like the looks of the Acme, but I want a freestanding unit without the outboard bearing, more like the N.Y. Safety engine.

 

[JorgensenSteam]

Here is the beginning of the cutout in the side of the frame.
I have a little more grinding to do to get it symmetrical.

The wall of the frame is a little thin in spots, but still workable, and the beading that goes around the cutout in the frame will stiffen it considerably.

Here are some tips if you are considering making a scratch bottle engine:

1. Steel tubing can be purchased from Speedy Metals (or others) in various diameters and wall thicknesses up to 1" thick. Layout your stacked disks carefully, leaving enough extra thickness between disks. Use the thinest wall section necessary for any given disk.
2. "V" the disks to allow a full penetration weld, but leave a small lip to allow the disks to be accurately aligned.
3. Turn the curved surfaces on the insid of the disks before you weld them together to allow easy access to the interior. Minor smoothing of the interior faces can be done with a long boring bar after each section is welded on, but before the next section is added.
4. I used multiple passes for the welded joints, and I chipped the slag and wire brushed between welding passes.
5. You can use a hand held grider to smoothe up the welded surfaces a little before you even then up in the lathe.
6. I neglected to do this, but weld a round rod on the bottom plate of the frame so that you can chuck the bottom of the frame in the 3-jaw chuck. The square bottom of the frame can be chucked into the 4-jaw, but then can be tricky to get aligned.
7. I cut a round recess into the top of the bottom plate before you weld it to the frame, in order to get the frame exactly in the center of the bottom plate.
8. I should have grooved the bottom plate to make it easy to open up a hole in it, since the bottom of the engine will be open, and needs to be open in order to weld the frame from the inside at the bottom.
9. Make a top flange and weld it in place, and then make a temporary top plate the same size as the bottom plate, and bolt it to the top flange so that you have two flat surfaces to bolt to the mill table. Add a round rod to the top plate so you can chuck the frame up in the lathe. Use a centerdrill in each round rod at either end of the engine, so either rod can go in the live center.
10. The bottom of the engine will eventually be turned round, but don't turn it until all the milling work on the side of the frame is done.

 

[Heatherrose]

Thanks for bringing us up to speed.
Nice progress and beautiful work in a short amount of time.
I am looking forward to the weekend and working on my build.


​

 

[Noitoen]

Keep up the good work. It´s going to look fine in the end.

 

[steamer]

That'll be a fun core box! Can't wait to see that Pat

Dave

 

[bezalel2000]

Nice work Pat!

Looks to be a lot of time put into those drawings, well done.
They really give you an upfront view of what the cores are going to look like.

I'll be following progress on this build with interest.

Good luck with your pattern building and don't forget th_wwp


Bez

 

[steamer]

I think anything below 3" bore will be pushing your luck on the cores. It's hard to get them to stay still and stay together in the small sizes.....You might get it in on a 1 1/2" size.....but below that....I'd wonder.

My passages were drilled which simplified the casting quite a lot!....just 1 cored hole, and I used standard size commercial core stock for that.

Dave

 

[Jasonb]

Pat, not sure if I gave you this link before but it shows the cores for a 6" traction engine cylinder. Lucky you are not making the twin a compound

http://homepages.tesco.net/~jean.george1/gmcylinderpics.html

Smaller is possible, Stuarts core their passages and the 10 series engines are 3/4" bore.

J

 

[Jasonb]

You don't need any dowels or any means of locating the pattern in the box.

Lay one half of the moulding box joint down on a flat surface, place one half of the pattern on the flat surface and ram up, turn box over and add the otherhalf of the pattern this will need locating lugs so it joinst the other half true. Dust the pattern and ram up. Pull the patterns and drop in the cores which locate in the core prints, these are the bits painted black in the link above. The cyl pattern will have to have these prints added to it you can't mould straight from it.

Well there is a bit more to it than that but that covers locating the pattern and cores.

For your engine the cylinder core can also incorporate the inlet cores so that supports them at one end, the other ends locate into pockets in teh valve chest core. The ends of the cyl core are easily located by core prints, valve chest core located posibly by valve rod hole but better just a big rectangular core print.