X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao09.cox.net ([68.230.241.30] verified) by logan.com (CommuniGate Pro SMTP 5.1.1) with ESMTP id 1503568 for flyrotary@lancaironline.net; Wed, 25 Oct 2006 11:40:42 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.30; envelope-from=dale.r@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao09.cox.net (InterMail vM.6.01.06.01 201-2131-130-101-20060113) with ESMTP id <20061025154019.SHRZ16798.fed1rmmtao09.cox.net@fed1rmimpo02.cox.net> for ; Wed, 25 Oct 2006 11:40:19 -0400 Received: from [192.168.1.100] ([68.2.134.48]) by fed1rmimpo02.cox.net with bizsmtp id efgP1V00P12ovmC0000000 Wed, 25 Oct 2006 11:40:23 -0400 Message-ID: <453F855C.5060805@cox.net> Date: Wed, 25 Oct 2006 08:40:12 -0700 From: Dale Rogers Reply-To: dale.r@cox.net User-Agent: Thunderbird 1.5.0.7 (Windows/20060909) MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Rotary Roundup References: In-Reply-To: Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit What Bill said. Plus, in the unlikely event that you can't get a drill bit
in the range of .002 - .005" less than your reamer size, it's okay to
drill smaller. I've reamed holes that were .010" smaller than finished
size with no apparent degradation in finish, but the tool life certainly
suffered. OTOH, I would only expect that to be a problem if the
tool was expected to ream hundreds of holes.

Dale R.

wrjjrs@aol.com wrote:

For the mechanical engineering comment of the day; Most o-ring seals REQUIRE a 32 microinch finish. This will NOT happen with a drill. For your injector o-rings you are sealing gasoline. (obviously) No halfway measures here! You simply MUST have a totally leak-free seal. Get the correct reamer. They are easily available in metric sizes. For the best finish leave .002-.005 in. of material when drilling. A 32 microinch isn't mirror-like, rather it is flaw free. (no scratches at all) Usually a shiny surface.

Bill Jepson