X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.123] verified) by logan.com (CommuniGate Pro SMTP 5.2.5) with ESMTP id 3050729 for flyrotary@lancaironline.net; Thu, 31 Jul 2008 22:53:03 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.123; envelope-from=echristley@nc.rr.com Received: from [192.168.0.19] (really [66.57.38.121]) by cdptpa-omta01.mail.rr.com with ESMTP id <20080801025224.LKNN14026.cdptpa-omta01.mail.rr.com@[192.168.0.19]> for ; Fri, 1 Aug 2008 02:52:24 +0000 Message-ID: <48927AE5.8040803@nc.rr.com> Date: Thu, 31 Jul 2008 22:54:29 -0400 From: Ernest Christley User-Agent: Thunderbird 2.0.0.14 (X11/20080505) 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 Dale Rogers wrote: > 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. But do you really want to use hardened bolts anchored in aluminum? Lynn said it the other day. It would be better to choose a bolt where you could get some stretch out of it before it pulls out of the anchor material. -- http://www.ronpaultimeline.com