Stuart Triple Expansion Engine

[Alec Ryals]

Well every thing came to a grinding halt today since I noticed that back in < 1960 Stuarts broke the casting spigot here rather than grinding it away, leaving little pockets about .030" deep and since I used that surface to center off of now I'm trying to fiqure out how to blend this all in so all the lines match up for the shielding, will return .
Alec

 

[Alec Ryals]

Well I got brave and quit snibbling about that intake flange that is ~.030 low and went off my original center-line anyway and went ahead and drilled the holes that hold the cylinders together, had my doubts but it worked out nice being pretty even on the depth of each countersink for the head of the screw, my mill is bottomed out on the z axis and will barely hold a # 45 drill or a 7BA tap.
I'll get-er-done yet .
Alec

 

[rhankey]

Alec, Nice work so far. I'm also slowly building a Stuart triple at the moment too which I'm showing in another thread, so I can well appreciate how much goes into the cylinder heads and especially how many holes there are to drill and tap. It looks like you are working with older higher quality castings than I had to work with.

With the IP exhaust spigot, are you .030" off after accounting for the thickness of the lagging? if not, you should be fine. I machined the cylinders to be 1.750" and 1.250" wide minus twice the thickness of the lagging so that when assembled, the lagging is perfectly flush with the sides of the valve chests and with the outer edge of the LP cylinder cover.

Good luck with the build, and keep up the photos.

Robin

 

[Alec Ryals]

Robin, Thank you and Great idea about the lagging being flush with the steam chests.
Alec

 

[Alec Ryals]

Well I'm out of camera battery's at the moment, Has any one else put a gasket between the HP & IP,LP cylinders hence I tried using no gasket on another steam engine and steam will leak out, I'm going to add the .016" TO THE STACK UP BUT MACHINE IT WITH NO GASKET IN PLACE, AS FAR as I can tell no one else has added a gasket here?
Alec

 

[rhankey]

I intentionally did not make any allowance for a gasket between the HP and IP cylinder heads when I was machining the cylinder heads to ensure perfect allignment between the pair of heads. If it turns out after assembly that I need a gasket to prevent leaks, then I will consider machining off the thickness of the gasket from the HP cylinder head.

 

[SirJohn]

This looks an e-Bay bargin?
Where do you start?

 

[Alec Ryals]

Yes it was a e-bog bargin till I found out there was no #1 engine in the package like there was supposed to be or any drawings except one page out of three for the triple and the #1 drawing and a reverse kit for the #1.
I like starting on the cylinders first, It took me a while to figure out how to reverse counter bore the screw heads for attachment of rhe HP to IP & LP cylinders, I first used a bur then went to a bur and used the back of it to counter bore, now the cylinders are a Unit. there was over 1/8" per side coming off the top and bottom of the HP cylinder so I used my shaper.
Alec

 

[Alec Ryals]

I think the next step I to make a rigid hone hence on my compound Elsworth auto machine shop charged me 2 hr's on the sunen hone >$100.00
YIKES he must of been Green on the hone claiming it was all in the set-up. and I left a little on the top & bottom for any bell mouthing.

 

[Alec Ryals]

I tried a set screw thinking it would be good to retain the option of adjustment , but there wasnt enough grip .

How about a dimple on the shaft under the set screw.
Alec Ryals

 

[Alec Ryals]

Does any one know what the brass plug (3/8-26) on the back side of the Intermident valve chest is for. as shown on drawing?.
Thank You
Alec

 

[rhankey]

It is an inspection hole to aid in setting the IP valve timing.

 

[Rivergypsy]

Looking good! I do love these engines

 

[Alec Ryals]

I wonder how one sets the timing threw that access hole on the IP cylinder?.
It also seems to me with that plug removed it could be run on air for display using the HP cylinder.

 

[rhankey]

All I can imagine, is that they figure you will scribe the center line of the exhaust port on the outside next to the inspection hole, which could line up with similarly scribed allignment marks on the side of the valve. When you fit the valve, you will notice there isn't any room to be gazing around with a flashlight through that hole. All you will see is the side of the valve. I need to finish making the steam pipes/flanges and paint the cylinders/sole plate then I will be ready to attempt final assembly and timing. If allignment marks don't help, I figure I might be able to achieve more accurate valve timing with compressed air on one cylinder at a time with the cylinder covers removed so I can tell exactly when the ports open/close. If that doesn't work, I have a couple Plan-B options I've been mulling over.

One option for running on compressed air would be to fit simpling valves onto the steam pipes. That way it could still be run on compressed air or steam, with the added benefit of also being self starting.

 

[Alec Ryals]

Thank you now I see the use of the plugged hole, Great idea about running on steam or air, I have used air to tune my compound getting each cylinder running the fastest but I'm not sure that's how to tune the LP cylinder on a compound but at the time it made sense to me and runs great on 10 LBS steam. I will try to add a video of it running well it won't work but it makes a sort of popping sound

 

[Alec Ryals]

Here are some more photos of my tooling plate for mt 7" South Bend shaper
On the second and last photo you can see threw the tool bit, hence it is in motion a ghost image.
Alec

 

[Alec Ryals]

On the second and last photo one can see threw the tool bot hence it was moving a ghost image.

 

[Alec Ryals]

I'm still confused about timing on a compound engine, My twin compound launch will run on air or steam, To time it I got each cylinder to run the fastest, then hooked them up and it runs on booth, This can't be right I would think I need to time the second cylinder (LP) using steam coming from the High pressure side and go for the fastest speed this way,as from what it shouldn't run on air but it screams to more air the harder and faster it turns -within reason.
Does anyone know about this I would be Great full.
Alec

 

[GWRdriver]

My triple was bought in England back in June 1960 for 13 pounds and 33 -- Wow

You only paid 8 pounds 3/ for the engine which in 1960s dollars is only $13!!