From: RWolf99@aol.com
Message-ID: <5a.11332d0b.27be1337@aol.com>
Date: Fri, 16 Feb 2001 00:23:03 EST
Subject: Holes in Firewall Stainless
To: lancair.list@olsusa.com
Reply-To: lancair.list@olsusa.com
Mime-Version: 1.0

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I have installed one firewall bulkhead fitting so far in my LNC2.  This was 
the one for the 3/8" fuel line to the gascolator.  It was easy to drill the 
hole by starting the hole in the stainless with a center drill bit from a 
lathe.  I then ran larger drill bits until I got the size I needed.  The 
problem came when I discovered the bulkhead nut needs to bear directly on the 
firewall plywood -- the fitting is too short to compress the fiberfrax and 
engage far enough for the B-nut to go on.  So I relieved the hole in the 
stainless and cut away the fiberfrax, and now the nut bears directly on the 
plywood with enough clearance for a socket to tighten it.  The clearance will 
be filled with red RTV before first flight.  So far, so good.

The problem was (and what I'm asking for better ideas on) is that I enlarged 
the hole in the stainless with a Dremel tool sanding drum.  Sparks a-flyin' 
and the stainless was so tough I went through 5 drums in the 45 minutes it 
took me to do this.  The final result looks very nice -- but there's gotta be 
an easier way.

Any suggestions for cutting big holes in the 0.023 inch stainless will be 
gratefully appreciated.  My hole saw wouldn't even scratch the stainless.  
Pretty soon I'll need to cut a hole for the cabin heat valve.

- Rob Wolf
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Please send your photos and drawings to marvkaye@olsusa.com.
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