[Steam-engine] Pitted shaft & Babbitt bearings

[James Hansen]

The bearings to be poured are split bearings.  You say
to repair the shaft first.  I intend JB to be the
repair.
_____
Oh, I see.


The pitting is on the counter shaft that runs
under the boiler to drive the the wheels.  This shaft
is slow turning and the filler will only see
compression loading.  I got the idea after reading
about stationary engine guys using JB to repair
pitting and scratches in cylinders.  I just need to
make the surface smooth again.  JB weld advertises
that their product will work up to 6000.
_____
6000?   JB weld is good to 500 degrees F
Lead melts at 621.5F
What am I missing?



The babbitt
will be hotter than that but only for a few moments.
________
Long enough


I have heard of the newspaper method instead of
smoking the shaft with a torch.  Are you saying that
the paper might give a little protection from the
heat?
_____

Nope, never said that, but on slow moving split shaft bearings, it works as
a built in clearance for your new bearing, and would smooth the
imperfections a tad.  How big are these pits you are talking about?  Wy not
just leave them and scrape the bearing smooth after?.

I have been checking around for product that will
stand high heat and JB is the best I've found so far.
Do you have other suggestions?
____
Brass. Yeah, I know you don't  want to hear that...   I doubt you will find
a polyester based filler that stands much over 500 degrees.  Permatex
Ultra-copper silicone gasket sealer is good to 700 intermittent duty, and
should do the trick for a filler.  I've seen some runny goo used to seal
leaky exhaust manifold gaskets on some trucks, but I don't know where it
came from, or what it is.  That would work too I would think.
-James

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