[Steam-engine] Boilers / Repairs

[Andy glines]

--- Dave Merchant <nesys_com at ameritech.net> wrote:
> My understanding of the problem is that the tension
> across the seam is 
> diagonal,
> rather than the straight pull you'd get from a pair
> of butt straps.
> Thus, you get a bending of the sheets near the lap
> seam.
> 
> Every time pressure goes up or down, the lap seam is
> flexing rotationally.
> This would presumably cause metal fatigue.
> 
> Dave Merchant
> 
Yea, what you said.  At steam school we learned that
these areas of high stress also erode faster leading
to thinning or grooving.  On a lap seam its a thin
area running parallel to the seam.  It also causes
ring around the staybolt.

=====
Andy Glines
Evansville, IN


		
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