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In a message dated 9/9/0 10:51:32 PM, Dan Schafer wrote:

<<If you have parts with interference-fit holes anodized, like pre-drilled
rivet holes, be aware that the process builds up a bit on the surface and
holes that were perfectly sized before the treatment won't be afterwards.
They'll have to be a thou or two oversized (check with the shop on the
build-up expected) before the anodize.>>

Dan brings up a very good point.  There is a dimensional change with anodize
that's small but noticeable where a thousandth or two makes a difference.  
However, my approach is different.  I'd do the precision hole drilling AFTER
anodizing, not before.  That way the hole size will be perfect.  Of course,
it won't be anodized where the drill went through, but there's usually grease
in one of these holes, isn't there?  If not, and you're really concerned, you
can always alodine the edge of the hole.

There is a much bigger dimensional change with powder coating, possibly up to
10 thousandths near a hole (I don't know exactly).  

I'm not aware of noticeable dimensional changes with alodine.  If you've got
an aluminum spacer, like the ones in the 320/360 elevator pushrods, and the
spacers fit prior to alodine, they will fit after alodine, too.

By the way, any of the options (alodine, anodize, powder coat) looks better
than zinc chromate primer, if you ask me....

- Rob Wolf
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