Steam locomotive full-crank axle

[Paul of Covington]

   Thanks, Balt.   I got a kick out of the human counterweights.

[BaltACD]

Building a steam locomotive - from scratch

http://www.youtube.com/watch?v=aHIEudnoRYU

[oregon shay]

Overmod and RCDRYE,

Thanks for the additional information.

Wilton.

[rcdrye]

Baldwin's half crank axles only worked with an outside frame.  Inside-connected locomotives with inside frames required a full crank axle. The increased wight and size of locomotives made the half crank obsolete very quickly.

[Overmod]

Here are a couple of good drawings that show the arrangement

...

[oregon shay]

Thanks for the explanation.  I appreciate the help in understanding this design.  I hope to find a drawing of it, and will post it if located.

Wilton.

[Overmod]

A full-crank axle would have two webs (per crank 'throw'), one each side of the journal where the rod runs (think of how an automobile crankshaft is arranged).  The half-crank axle uses the wheel as one of the two webs, both saving weight and allowing the rods to be closer to the plane of the wheel (and pass around things like a Bury firebox structure, in the case of an early Baldwin).

Interestingly enough, most of the four-cylinder locomotives I've seen have full inside webs for stronger construction.

If this doesn't answer the question, PM me.

[oregon shay]

While re-reading a favorite book on the history of Baldwin locomotives, I noticed a reference to full-crank and half-crank axles during a discussion of early steam locomotive drive design.  A drawing was included in the text about the half-crank axle, showing it's design, but something similar for the full-crank version is not described or shown.  A Google search of the internet yielded nothing helpful in the way of description and/or images.  Can any forum members point me in the right direction?  Many thanks.

Wilton.