[SEL] Babbitt Lapping Compound

[James Mackessy]

This sounds very similar to the old "Bon-Ami" kitchen cleanser trick.
Mechanics used to pour it into a fast running engine's air intake to help
seat in a new ring job. It laps, but breaks down quickly into finer and
finer particles. I think I'd want a thorough cleaning afterwards, no matter
what the use. I forget what the mineral is, but there is either pumice or
some type of feldspar in Bon-Ami.
Regards;
Jim Mackessy
----- Original Message ----- 
From: "Richard Strobel" <Richard_Strobel7 at msn.com>
To: "The SEL email discussion list" <sel at lists.stationary-engine.com>
Sent: Thursday, November 01, 2007 9:12 AM
Subject: Re: [SEL] Babbitt Lapping Compound


> What comes to mind Curt,, and Elden and the Doc might remember is the old
> cleaner used on TV rotary tuners.  First it was a mild abrasive, then
> polished and I believe lube might have been the last result....might need
> help on the lube part :-))
>
>   If in fact this compound did the above, I would be willing to try it on
> some babbitt....diamond would be a definete no-no with babbitt, IMO.
>
>   What I've got now is a super heavy single throw crank with the rod throw
> radius' out of whack and un-even.  The rod throw mates to bronze inserts
> which show evidence of the un-even radius' (sP).  I'm thinkin' a visit to
> the crank Doc in Missoula is in order.  He did a great job on the Gal
after
> the wreck.
>
> and Jack might be right..I was impressed on how forgiving pumice is to
> porcelain....very hard water deposits here.
>
>
>   Will do more research with the guy that uses it on his Model A's.
>
>
> Take care...warm fall here so far....priority now is wings on the
> snowplow....aaarrghhh.
>
>
> Rick
>
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> Rick,
> When I use lapping compound on bushings for our forging machines here at
> work, I remove the cap and place a small amount of the compound at the
> point along the bushing & shaft where the bearing is tight. I place it
> at the junction between the shaft and edge of the bearing, where the
> shaft rotation will sweep the compound into the bearing. I then put the
> cap back on loose and fit a large funnel to the oil inlet. Then run the
> machine and slowly pour about a quart of oil (320 vis) thru the funnel,
> literally attempting to wash the compound, and the wearing away bearing
> material out of the bearing. I use diamond lapping compound (5 micron)
> and it works in seconds, so getting it back out of the bearing is of
> paramount importance, otherwise a low bearing results.
> This process is on 660 brass bushings. I have never tried on babbitt
> bearings. They claim it does not imbed in the babbitt, but that would
> sure be my concern. I lean very strongly to "scraping" the high spots
> away on babbitt. Babbitt is SO easy to work with, one could almost get
> the "lazy" title associated to their name if they aren't will to invest
> a minimal bit of time scraping in soft babbitt bearings. I don't even
> use official scrapers on babbitt, just hit the high spots with a very
> course rat tail file. This works great and is fast.
> Curt
>
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