[Steam-engine] Valve Seat, too smooth

[James Mackessy]

Andy;
     I think a lot of old-timers would have gone with a hand scraped finish,
which
would give you the oil holding ability you are worried about, but I have
only found
evidence of this on one engine so far. Of course, most of the others were
"million
milers" and corroded past the point of showing even if it was there
originally. With
the right tools and a bit of practice, it is not hard to put "fish scales"
or "crescent"
patterns on a flat surface, and this would be enough to hold oil. I have
done this on
machine tools and even large slides on injection molding dies to prevent
galling. If
there is a machine rebuilder or an old time tool and diemaker in your neck
of the
woods, perhaps you could have it done reasonably. I'm interested to hear
what
others have to say on this topic, it's a good question.
Best Regards;
Jim Mackessy
----- Original Message ----- 
From: "Andy glines" <pioneersop96 at yahoo.com>
To: "Steam" <steam-engine at lists.stationary-engine.com>
Sent: Friday, May 06, 2005 9:06 AM
Subject: [Steam-engine] Valve Seat, too smooth


> As I was working on honing the valve seat to remove
> the cutter marks I began to wonder if I need to worry
> about getting the surface to smooth.  The D valve is
> already very smooth with a ground finish and the is
> well in its way to being just as slick.  I know that
> if we get cylinder walls to slick on a gas engine oil
> won't stick to the cylinder walls and there is a lack
> of lubrication for the piston.  My initial thinking
> was to get the seat as smooth as possible so that it
> will make a better bearing surface.  Should I go for
> super smooth or should I leave faint traces of the
> tool marks to hold oil?
>
> Andy Glines
> Evansville, IN
>
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