Tiny triple expansion steam engine

[b.lindsey]

Great set up for doing those George. They certainly should be very nearly identical too.

Bill

[gbritnell]

Some pictures of the valve straps, valve rods and clevises. The valve rods are threaded into the clevises with 0-80 thread. The valves will be located with 1-72 set screws.

[gbritnell]

I finished the eccentrics then made the support brackets for the reverse shaft. I had the main bearings mounted with socket head screws which was only temporary so it was time to start making more hex head bolts, this time 1-72. I had started with the drawing for the Stuart compound launch engine but I see as I'm assembling parts that the valve straps are going to hit the crosshead support bracket. They shouldn't but they are so a little modification is in order.

[Admiral_dk]

Fantastic work George 

I have been wondering for some time about what keeps the "bracket" a quarter up the "collums" on this side of the picture ...?... On Jo's much bigger version there are two small grub/set screws on the "inside" ....   

[tghs]

as in the next few months I'll be making 2 piece box links for my navy engine looking at your method gives me hope that I can do as well..

[gbritnell]

The engine is finished timed and assembled. All that's left to do is the plumbing. I did run across something curious while trying to time the engine. The Stuart drawings for the compound launch describe the eccentrics centerlines as each being 20 degrees above the horizontal centerline or in other words 140 degrees apart. I made the eccentrics to these dimensions but when I tried to time the engine I couldn't come anywhere near to the proper timing. I set my valve for equal travel then adjusted the eccentrics for the proper time in one direction. When I reversed the linkage the valve timing was way off so I did a layout in Cad and came up with 5-1/2 degrees above the centerline or 169 included angle. I made new eccentrics to these dimensions and after disassembling the whole engine to get to the I.P. eccentrics I put everything back together and started over. I set the valve for equal travel then set the timing for forward motion. I then reversed the engine and found that I was off ever so slightly so I split the difference and everything seemed to be fine. Why this occurred I don't know as I built the compound launch to the Stuart dimensions and as I recall it seemed to time fine.
Anyway at this point I'm happy with the timing so here's some pictures before I build the pipework.

[gbritnell]

Here's the last set of pictures. The last one has an American half dollar (1.20 diameter) sitting next to the engine for a size comparison. The engine turns over freely although a little snug but considering all the joints and moving parts that's to be expected. A little run-in time on the lathe should loosen everything up.

[b.lindsey]

Another "tiny" beauty George. Can't wait to see it running. Also can't remember the last time I saw a half dollar but hey, it works for scaling purposes 

Bill

[mike mott]

Certainly a handsome engine George.

Mike

[scc]

Absolutely beautiful work George     I cannot imagine working at this scale   big fingers, tired eyes,  etc
Regards         Terry

[90LX_Notch]

George-

Amazing work as always. 

-Bob

[crueby]

Wonderfully done! Even more so once you see the coin!

[steamer]

There it is....love a nice triple!.....that one is even nicer!....

Dave

[Kim]

Beautiful, George!
Kim

[MJM460]

A beautiful result, and an education looking over your shoulder, thank you.

Now Looking forward to seeing it run.

MJM460