[Steam-engine] Pouring Bearings

[Stacey Freeman]

Andy, When I pour Babbitt, I build my forms around the shafts from plywood
and seal the shaft and shells to the plywood with 100% clear silicone
(bathroom tub seal).  The silicone will not burn or release and during
preheat, if the plywood catches on fire, that will not be a problem.  As far
as determining the heat of the shaft, I heat it to the point where I can't
put my had on it and hold it there.  I use Pam to release the Babbitt from
the shaft and that works well.  As far as the temperature of the Babbitt:  I
use a sugar pine strip of wood that I stick in the molten Babbitt and pull
it back out.  When the stick scorches dark brown it is hot enough. 

Just the way we do it.
Stacey Freeman
www.freemansmill.com

-----Original Message-----
From: steam-engine-bounces at lists.stationary-engine.com
[mailto:steam-engine-bounces at lists.stationary-engine.com] On Behalf Of Andy
glines
Sent: Thursday, March 09, 2006 8:45 AM
To: Steam-engine mailing list
Subject: Re: [Steam-engine] Pouring Bearings

Looks like I will have to respond to myself.  I was really hoping to hear
from some of you regarding my questions about babbit temp and shell preheat.
I am still trying to figure out how to preheat the shaft with the bearing
cap in place.  Any tips that you folks care to share with the novice?  

--- Andy glines <pioneersop96 at yahoo.com> wrote:

> I took the plunge and tried my hand at pouring bearings Sunday 
> afternoon.  I started with the shaft that drives the wheels because 
> alignment isn't critical on the Huber design.  So far, I have only 
> poured one half of the two bearings.  I have learned a few things and 
> now have a few questions.  I learned that I can't trust Babbitrite to 
> stay stuck to the shaft and shell unassisted.  Dad was preheating 
> while I melted  babbit.  When the shaft and shell got good and hot the 
> Babbitrite fell off.  We were able to secure more putty without losing 
> preheat. This time the putty was secured with wire and plumper's tape.
> The bread pan I placed under the shell turned out to be a very good 
> thing when a plug in an oil hole blew out.  The pan caught the babbit 
> and it was easily recovered.  I am using the book "How I Pour Babbit 
> Bearings" by Gingery for reference.  Using the book's suggestions the 
> shell was preheated until a piece of solder just started to melt and 
> the shaft heated to about 300 deg.  I am using tin-based babbit so I 
> heated it until my wooden stir stick caught fire.
> The
> cooled product looks pretty good.  The ends of the new bearing are 
> nice and shiny but it is dull gray near the center where the cooling 
> was a bit slower.  I think that I may have been a little hot on my 
> preheat and my babbit and plan to back off on temperature a little 
> when I pour the caps.  One thing in my book confuses me a little.  The 
> book tells us that tin-based babbit should be poured hotter than 
> lead-based.  I thought that lead has a higher melting point than 
> tin???  Is the book backwards?  We used a propane weed burner for 
> preheat and found that it works very well.  I'm getting ready to pour 
> the caps.
> I will shim the caps and secure them to the top casting.  I can 
> preheat the shell OK but how do I
> preheat the shaft with the bearing cap in place?    
> 
> Andy Glines
> Evansville, IN
> 
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Andy Glines
Evansville, IN

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