[SEL] White metal to bronze question

[Curt]

Russell,
I've had a read of your post several times and am a bit confused. Elden 
seems to be replying to repairing a big end on a conn rod, yet your post 
seems to be asking about the crankshaft mains.
You say the crankshaft has a "bit of jump in the bearings (plural) 
itself " and I take it this is the mains supporting the crankshaft.
You also mention the existing brass mains..... Hope this is not too 
stupid a question, but why not just turn up a new set of brass bushings 
and drop them in the saddles? Seems this would be easier and a whole lot 
more accurate than building up the old ones with babbitt.
Curt Holland
Gastonia, NC

Russell Gilbert wrote:
> Thanks Elden, sounds pretty easy if you say it quick. Also seems 
> similar to an off list reply I got also. Many thanks; I will endevour 
> to do it over the next couple of weeks - to busy with work again at 
> the minute. I will report my experience when it's done. regards Russell
>
> At 03:26 AM 21/03/2007, you wrote:
>   
>> Russell:
>>
>> If you can get the big end into a lathe or mill, most of the 
>> critical work is easy.  Beings I've never rebabbitted a bearing 
>> (scraped in a set of mains on my American LaFrance a few years ago), 
>> I might give some wrong advice.
>>
>> To make the babbitt stick to the bronze, first clean up the surfaces 
>> with sandpaper, etc. and use a good solder flux and tin the bearings 
>> with babbitt until the surfaces are completely covered.
>>
>> To keep the babbitt from sticking to the mandrel, one way is to use 
>> an acetylene torch with no oxygen to smoke the mandrel.  Babbitt 
>> won't stick to the carbon.
>>
>> Before pouring the bearing, make up several shims so you can take-up 
>> wear in the bearing in the future.  I suppose you'd be good to go 
>> with about 0.030" or so of shims.  Then, assemble the bearing with the shims.
>>
>> If you can easily machine the new babbitt to fit the journal, you 
>> can leave a gap of 1/8 inch or so between the mandrel and the 
>> bearing.  This will allow the white metal to flow to all parts of 
>> the bearing.  Also, you need to heat the bearing to very near the 
>> melting temperature of the babbitt so the poured metal will fuse to 
>> the tin coating.
>>
>> After the whole works has cooled, machine to fit.
>>
>> Take care - Elden
>> edurand at mchsi.com
>> http://www.oldengine.org/members/durand
>>
>>     
>>> -----Original Message-----
>>> From: sel-bounces at lists.stationary-engine.com
>>> [mailto:sel-bounces at lists.stationary-engine.com]On
>>>  Behalf Of Russell
>>> Gilbert
>>> Sent: Tuesday, March 20, 2007 06:09 AM
>>> To: The SEL email discussion list
>>> Subject: [SEL] White metal to bronze question
>>>
>>>
>>> Howdy ya all.
>>> I want to have a go of fixing the bearing gap (if
>>> you like) in the
>>> big Graham engine I have. It runs fine but has a
>>> little jump in the
>>> crank shaft in the bearings itself on the
>>> compression stroke. So yes
>>> they are warn, but not major or it does look like
>>> a major problem
>>> anyway. Some of my past engines have actually had
>>> a very thin layer
>>> of white metal placed on the original bronze
>>> bearings so I thought I
>>> could do the same thing. I have plenty of white
>>> metal. Just have
>>> never used it before. How would I go about
>>> melting the white metal
>>> and attaching it to the bronze bearings. I
>>> imagine I would clamp the
>>> bearings together and put something similar in
>>> size to my crank shaft
>>> inside. Melt the white metal and pour! But I need
>>> to prep the bronze
>>> surface area first ... Yes? How would that be
>>> done? second when I
>>> pour the metal ...... should the bronze be
>>> preheated at all? and what
>>> should I use to on the shaft bit so the metal
>>> doesn't stick to it
>>> when I remove it from the set casting?
>>> I have never done this stuff before so I will
>>> probably stuff
>>> something up but one will not learn if one does
>>> not have a go.  In
>>> case some of you are wondering how big the gap I
>>> trying to fill is
>>> .... I would have a guess to say about the
>>> thickness of 2 to 3 playing cards.
>>> regards Russell
>>>
>>>
>>>
>>> Russell Gilbert
>>> Sunny Sunraysia
>>> russell at ncable.com.au
>>> http://community.webshots.com/user/russellsrelics
>>>
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>>> SEL at lists.stationary-engine.com
>>> http://www.stationary-engine.com/mailman/listinfo/sel
>>>       
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>
> Russell Gilbert
> Sunny Sunraysia
> russell at ncable.com.au
> http://community.webshots.com/user/russellsrelics 
>
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