Tandem Compound Poppet Valve Steam Engine Build, ala Cedge

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Brass_Machine:
:jaw: :jaw: :jaw:

That is all!

Eric

oh yeah! :bow: <---- that too

cedge:
Thanks everyone.

I'm taking my time, trying to get it right as I go along. The window technique itself is not my original idea, if I've given that mistaken impression. There is a German fellow who built a pair of engines, similar to these, and put up a build log on his web site. I've poached a number of his ideas even as I've added some of my own. That only seemed fair since he's poached one of my best animations for use as a signature image on his site.

Steve

cedge:
I didn't get a lot done today, but what was accomplished tied up a few loose ends that were bugging me. The windows on the cross head guide are now filed and rounded to their final size and shape. They turned out to be a somewhat delicate feature that added a nice bit to flair the project. The second engine's guide will begin tomorrow and I'm hoping it will turn out even better than this one.

http://cedesign.net/steam/images/misc/multi-valve/build/guide-13.jpg

The rest of the progress was limited to getting the gland nuts made and fitted to the glands. These were turned from a 1/2 inch piece of hex brass that made it easy to make.... you got it.... hex nuts....(grin)

http://cedesign.net/steam/images/misc/multi-valve/build/gland-2.jpg

You'll notice the gland nuts are flat on the thread ends. When I drilled the holes to thread the gland body, I left the taper the end of the drill bit created. The flats will press the packing into the taper and against the piston rod as the gland nut is tightened. Since I used a 3/8 x 32 TPI this arrangement will allow me very fine adjustment to control how snug the packing is compressed. the nuts were drilled .010 over the size of the 3/16 piston rod. Since the gland was reamed to size, it will hold the rod concentric, negating the need to add additional friction points in the nuts.

http://cedesign.net/steam/images/misc/multi-valve/build/gland-1.jpg

Here are the two gland nuts were what had me a little worried about the length of the original spacer between the cylinders. They even added something to look at through the small windows. Looks like I'll need to center them up a bit before I'm done.

http://cedesign.net/steam/images/misc/multi-valve/build/gland-3.jpg

The strange silver looking string is the graphite impregnated material Zeusrekining shared with me during the Water Pressure Engine project. This stuff makes perfect stuffing for the glands and acts as a lubricant was well. It remains low friction even after it has seated and worn in. It's available from McMaster Carr as well as Smallparts.com.

http://cedesign.net/steam/images/misc/multi-valve/build/gland-4.jpg

Here are the pieces all fitted up and awaiting the stuffing.... among other things....(grin)

http://cedesign.net/steam/images/misc/multi-valve/build/gland-5.jpg

Steve

MikeA:
Hi Steve,

As usual, I'm just catching up with this build and you continue to impress with both the quality of work and even more so, the ingenuity demonstrated in some of the procedures you use - almost makes it look easy!

Can hardly wait for the final product a la Cedge.

Best,
Mike

cedge:
Bob
Thanks for the tip. I typically deburr holes with a countersink, which leaves a taper in the end of the hole.... so I guess I do add a bevel in the nut without really thinking about it. See what I mean by habitual things are difficult to document?

I'm trying to keep these two engines fairly close to the same level of completion, as I go along. That means that I have to consciously stop and assess what is falling behind on one or the other as I work my way through test fits and such. Today I managed to bring both engines to the same place and got a lot of small things accomplished.

The second crosshead guide is almost done, needing only a bit of hand work on the window and some cleaning and polish. It was a little tricker to make since the bead on the end of the cylinder was intentionally cut smaller than the rest of the ends by a full 1/8 inch. Lucky for me my calculations were right on and I didn't have to change the hole pattern to make it work.

While the engines are of the same basic design, I've decided to give them different details. The single cylinder version will have the piston rod exposed on both ends just to give it a bit more motion when running. The tandem engine now has a longer crosshead window which will hopefully allow me to use a novel oiler system. Other small things will receive cosmetic differences as things progress.

Here are the two engines as they sit a the moment. Sorry, but the things I accomplished over the past couple of days were simply repeats of things in previous posts. No one wants to see photos of all of the nearly 150 small holes the project has required so far....LOL

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