[SEL] RE: Pitted shaft & Babbitt bearings

[Curt]

OK Andy if you think this is a really dumb idea then just delete it.
I gather the reason you've decided to not replace the short jackshaft is 
cost??? Since you are concerned about filling in the pits (I'd blast and 
use titanium Devcon) and have learned that JB won't take the pre-heat 
for babbitt pouring. How about this.

Before filling the pits, carefully cut and wrap the shaft with a piece 
of .003 or .004 thick stainless shim. Have it extend and inch or more 
beyond the bushing area and use a pair of hose clamps to hold it in 
place. You might have to use thinner material and do a couple of wraps 
to get it to lay flat. The idea is that you will have a super slick 
surface to pour against and this will also build in the proper running 
clearance.

Once you've poured, then you can remove the shaft and stainless shim 
stock, sand blast the pits in the bushing portion of the shaft and use 
the titanium Devcon. You may have to enlist the help of a friend with a 
lathe to finish the Devcon. It is damned tough stuff. A file isn't real 
effective!

I have no experience using stainless as a babbitt form and only toss it 
out there as a possibility.
Curt Holland
Gastonia, NC
P.S. Could you use a piece of thin wall 3 1/2" DOM tubing as a dummy 
shaft for pouring? That should be cheap enough.....


Andy Glines wrote:

> As usual, I get some great ideas when consulting ATIS lists for 
> ideas.  There have been several good ideas given.  I'm afraid that 
> leaving the pitts alone simply won't work.  The pitted area is 
> actually a strip about 1.5" wide for the length of the bearing surface 
> on both ends of the shaft.  I'm thinkg that this is where rain water 
> got in through the oil troughs and sat on the shaft.  Besides the 
> rusted strip the shaft is pretty smooth.  Leaving this area alone will 
> result in a big gap in the bearing surface that I think will cut the 
> bearing quickly.  When I first posed this question I thought that the 
> bearing castings were permanently attached to the boiler.  Further 
> investigation shows that they can easily be taken off where I can put 
> them on a table.  Being able to take them off means that the dummy 
> shaft might work well.  Of course I've gotten some links to higher 
> temp fillers.  Arnie asked what size the shaft is... 3.25" or 3.5" 
> about 54" long.  I had already considered his idea that a shaft of 
> sufficient size could act as a heat sink and therefore the filler 
> would only see the extreme heat for a short time.  I'm pretty sure 
> that this shaft is big enough.  As always you folks have give me food 
> for thought.  Thank you!
> BTW The shaft in question is the countershaft that drives the wheels 
> on my Huber steamer.
>
>> Message: 38
>> Date: Tue, 19 Apr 2005 17:53:21 -0400 (EDT)
>> From: Arnie Fero <fero_ah at city-net.com>
>> Subject: Re: [SEL] Pitted shaft & Babbitt bearings
>> To: The SEL email discussion list <sel at lists.stationary-engine.com>
>> Message-ID: <Pine.BSF.4.51.0504191740430.48218 at vegeta.city-net.com>
>> Content-Type: TEXT/PLAIN; charset=US-ASCII
>>
>> Hi Andy,
>>
>> As an alternative to JBWeld, McMaster-Carr lists a couple of high
>> temperature epoxy putties.  One for aluminum rated to 1400 deg.F and one
>> for cast iron, steel, and stainless rated to 2000 deg.F.  Under $30 
>> for 8
>> oz.  Look for 7356A33 (or 7356A32 for the aluminum).
>> http://www.mcmaster.com/
>>
>> They also carry the high temperature titanium Devcon rated to 350 deg.F.
>> That's a bit higher at $65 for a pound.
>>
>> Realistically, you could probably use the JBWeld also.  The worst that
>> could happen is that some of it burns out leaving a lesser pit than you
>> have now.  You'd still need to scrape that as Larry describes, but it
>> would probably be less scraping than if you left the pits unfilled.
>>
>> What diameter is the shaft?  If it's beefy, the heat sink effect of the
>> shaft would probably conduct enough heat away that the JBWeld 
>> wouldn't be
>> badly damaged.
>>
>> Or just drop $30 and go for the high temperature stuff.  8-))
>>
>> See ya,  Arnie
>
>
>
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