X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao104.cox.net ([68.230.241.42] verified) by logan.com (CommuniGate Pro SMTP 5.2.5) with ESMTP id 3049055 for flyrotary@lancaironline.net; Wed, 30 Jul 2008 20:27:34 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.42; envelope-from=dale.r@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao104.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20080731002655.KSIL6526.fed1rmmtao104.cox.net@fed1rmimpo02.cox.net> for ; Wed, 30 Jul 2008 20:26:55 -0400 Received: from [192.168.1.100] ([72.223.44.12]) by fed1rmimpo02.cox.net with bizsmtp id wQSv1Z00N0Flgvc04QSvc7; Wed, 30 Jul 2008 20:26:55 -0400 Message-ID: <489106CE.7060105@cox.net> Date: Wed, 30 Jul 2008 17:26:54 -0700 From: Dale Rogers User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Safety wire References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Bill, "Case hardened" or "Through-hardened"? Either way, ditto on the cobalt drill bits, or for hole sizes larger than #20, maybe even "solid carbide". FWIW, I do case hardening. It is typically done to give a wear-resistant surface on a part that otherwise needs to be somewhat ductile underneath - which won't be the metal's strongest state. Dale R. wrjjrs@aol.com wrote: > Kelly, > That is true "except" that the better quality allen bolts, > Holo-Chrome, SPS, etc are case hardened. Be sure you get cobalt drills! > Bill Jepson > >