Re: An eccentric idea for valve setting

Thank You for an excellent thread, Kelly and Russ -

I've read about this process previously, but youse guys have explained the many steps very clearly and the photos are great.  I especially appreciate Russ's treadmill that makes rotating the eccentric crank to the exact position so much easier – what a GREAT idea!!

A couple of years ago I started on a series of drawings showing the valve events at different points in the cycle, but got bogged down in other things and never finished them.  Here's just one of about two dozen that at least shows some of the (somewhat simplified) main components.  The red shading represents live steam entering the cylinder, the blue represents exhaust steam being pushed out as the main driver turns forward (clockwise):


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Russ489 Wrote:
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> Sadly, I am not aware of an easier way to
> adjust the lengths of the eccentric rods.

Have you thought about using an eccentric bushing on the link end of the eccentric rod, Russ, or on the link itself – sorta like this?



Since we're talking about only a few hundredths of an inch here, I've exaggerated the offset in the drawing quite a bit.  Depending on how it's oriented, the offset of the bushing would have the effect of slightly lengthening or slightly shortening the eccentric rod.  It wouldn't be affected by the rotary motion of the crank if it were on the front (link) end of the rod, but would probably still need a key (shown in red) to keep it from shifting.  I don't think the effect of the orientation of the offset on the length of the link itself would be enough to matter.  Of course this is moot with #489's eccentric rods - recently adjusted in the forge - but maybe it would make adjustments easier with the other locos.

- El Abuelo Eccentrico



Edited 2 time(s). Last edit at 02/07/2017 07:59PM by Russo Loco.