Dear List,
I have Porter's book on B restoration, and I am trying to figure out what
is involved in replacing sills. So far, every B I look at needs them.
Porter's book leaves some critical things unsaid, and I need advice from
somebody who actually has seen the innards of B sills (either by
replacing them, or by seeing them gradually appear to view).
Porter shows ripping off the outer sill to show an inner membrane with
various triangular pressings for stiffness. Below this, and forming a
sort of upside down T with the inner membrane is something called a castle
section, for unknown reasons. In his example, which looks pretty grotty,
the inner membrane and the castle section are toast. When the remains of
these are cleaned off, there is what appears to be a flat vertical plate
which is fairly sound even though everything else was eaten away. He does
not mention what this is, and does not seem to consider that this might be
rotten, too.
So what is the third vertical membrane seen after the outer sill and the
inner membrane and castle section are removed? Is this just the vertical
side section of the floor??? Why does he assume this will be sound--does
the rust almost always stop after eating the inner membrane?
Can any ascii artist who knows his/her Bs draw for me the cross section
of a B sill, including how the floor attaches?
Where is the jacking point reinforcement welded? To what I am assuming
must be the side of the floor, to the center membrane, where?
Help, please. I have good spatial ability in general, but I cannot
figure this out from the pictures.
Ray Gibbons Dept. of Molecular Physiology & Biophysics
Univ. of Vermont College of Medicine, Burlington, VT
gibbons@northpole.med.uvm.edu (802) 656-8910
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