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Cydrome Leader

Gunner Asch wrote:
On 1 Oct 2007 02:28:00 GMT, (DoN. Nichols) wrote:

According to Tony :
One thing i've noticed over time in rebuilding these pumps is that grit and
metal filings seemed to get embedded in the composite plastic vanes
(probably debris that got passed the strainer) and scores the pump
housings.

I was leaning towards aluminum vanes since I think they are less likely to
do damage to the cast iron housing. Brass or bronze might be even
better/longer lasting.

Note that when lapping, the harder material is what is cut,
because the abrasive embeds in the softer material. So based on that,
you would want steel for the vanes.

But something like graphite which does not tend to accept things
embedding in it, but which wears to conform to the contour of the
housing would perhaps be the best choice.

Good Luck,
DoN.

The air pump vanes in my "torpedo heaters" use graphite vanes

Gunner

Year ago I spoke to some people at Precision Scientific about why their
vacuum pump vanes went from graphite to metal. The reason I was told was
graphite allowed for a less accurate initial fit, and would wear into
place, but that wasn't a problem these days and metal vanes that last
longer if they're made to the right size the first time.