Vertical steam engine with Stuart cylinder

[Michael S.]

In another post, I repaired a Stuart 7-cylinder, and now I'm building a new steam engine. The bore and stroke almost match the cylinder of a French blueprint, so it will be a vertical engine.

First, the upper plate is made from brass. The four columns and the crosshead guide are attached to this plate. Drilling and milling were done on the milling machine, and the curves were finally filed.

Michael

[Sanjay F]

Very nice use of the cylinder you restored Michael - looking forward to seeing you build it 

[Michael S.]

The cylinder now has a brass jacket.

The blueprint shows that the two rods for guiding the crosshead are attached at the bottom with a bridge between two columns. But what happens at the top of the brass plate? Slotted holes are provided there, but how should it be attached? Has anyone ever built using this blueprint?

Best regards, Michael

[PaulR]

That looks fantastic 

[Jasonb]

Do you have the two CSK holes on the correct side of the cylinder end cover? Quite common to have CSK screws into threaded holes in the ends of the guide bars.

The slots on the original plate allow you to drop the whole cylinder, cover,guide, crosshead, etc into place

[Michael S.]

Hi Jason, you have to help me. What are CSK screws? Countersunk screws?
It's probably used like that at the bottom end. I can see that in the first image of the computer animation. There you can also see that the guide rod isn't round. A square shape is better. In the blueprint, it's round. I assume it's simply inserted into the plate at the top. I'll do it that way.

Michael

[Michael S.]

The distance between the two rods in the upper area is not the bolt circle diameter of the 6 cylinder head screws.

[Jasonb]

What is the distance between the inside faces of the guide bars? If something like 20mm than two flats machined onto the spigot would allow the bars to be screwed on to that.

[Michael S.]

Thanks Jason for the helpful advice.
I drilled a 3 mm hole in one of the slots (notches). I could insert the rod there with a tenon or file a square hole.
But your last suggestion is good, and I could do it that way. Thanks.

Michael

[Michael S.]

I'll continue with this now. A vertical steam engine that will get a cylinder from a Stuart 7, and underneath it will be a Duval engine. I think it will work well together.

The piston and piston rod are finished and will be installed. The stuffing box and an oil reservoir have also been made. But there's still a lot to do.

Michael

[Sanjay F]

Looks like its going to be a nice looking engine 

[vtsteam]

 

[PaulR]

I've looked at those plans numerous times but don't recall seeing a completed engine.... looking forward to seeing this! 

[Michael S.]

Yes, Paul, I haven't seen a finished engine yet either.

Today was a day where I did a lot of filing. The valve body was actually already finished, but the surfaces were still raw cast iron and not at right angles. There was a large "7" on the cover. I smoothed the cast iron surface with the file and removed the "7" from the cover. I filed everything smooth and at right angles. I left the cast iron surface on the cover as it was. It looks quite good to me. I made the six M3 nuts myself because the standard M3 DIN nuts are too shallow.

Regards, Michael

[Michael S.]

The slide valve is finished, and the slide rod has been threaded with an M4 x 0.5 thread. I think this will allow for more precise valve adjustment. The joint at the lower end of the rod is also complete.

Since my plan is to eventually run the engine on steam, all the seals are coated with steam oil and graphite paste.

According to the Stuart 7 plans, the slide valve stroke is approximately 4 mm.

But at 4 mm, the steam inlet doors aren't even half open! They only open fully at a stroke of 6 mm. The dimensions of the slide valve and the cylinder match the plans. We'll see what I can do about that.

Michael