X-Mozilla-Keys:                                                                                 
Russell Kent wrote:

Paul wrote:

Since the density of the ceramic balls is only half of that of  steel balls  I would
be skeptical about using them in a turbo designed to run at high speed all the time
such as would be used in an aircraft engine.

Russell Kent replied:

I fail to see the connection between ball bearing density and reliability of the
bearing.  If denisty is all that important, let's use lead (or depleted uranium :-)

Paul replied:

No No Russell. It is low density that is important. Not high density.
I just don't think the $400 extra is worth it for aircraft applications.
I could be wrong. To some people $400 is dinner.

Ok, so just to recap: you think the ceramic ball bearings aren't worth it because for
$400 they are only 50% less dense than steel ball bearings.  I recognize your point, but
I am unable to translate the lower density of the ceramic balls into a meaningful dollar
value.  I'm sure it is some function of "how much longer the turbo lasts".

I don't know if they are worth it in that regard.

But, your original comment seemed (to me at least) to place the durability of the
ceramic ball bearings into question.  If the ceramic ball bearings *aren't* more durable
than the steel ball bearings they replace, then why would anyone buy them?  I think
question is *how much* more durable are they?  (So we can compare the $400 price
difference to some measurable gain).

I value your opinion; I just don't see the reasoning in your original statement.

Russell

No question that they are more durable than ball bearings but
not as cheap as plain bearings and maybe not any better for our
application.

I think we covered all this in a later message Russell.
When things are moving this fast we sometimes have to slow down
and read everything.

Paul Lamar
 
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