X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-d20.mx.aol.com ([205.188.139.136] verified) by logan.com (CommuniGate Pro SMTP 5.2.5) with ESMTP id 3049954 for flyrotary@lancaironline.net; Thu, 31 Jul 2008 12:10:33 -0400 Received: from WRJJRS@aol.com by imo-d20.mx.aol.com (mail_out_v38_r9.4.) id q.c6d.2e27803f (37552) for ; Thu, 31 Jul 2008 12:10:29 -0400 (EDT) Received: from smtprly-ma03.mx.aol.com (smtprly-ma03.mx.aol.com [64.12.207.142]) by cia-mb03.mx.aol.com (v121_r2.11) with ESMTP id MAILCIAMB031-92b04891e3f533f; Thu, 31 Jul 2008 12:10:29 -0400 Received: from webmail-nh12 (webmail-nh12.sim.aol.com [207.200.84.131]) by smtprly-ma03.mx.aol.com (v121_r2.11) with ESMTP id MAILSMTPRLYMA031-5c534891e3e733a; Thu, 31 Jul 2008 12:10:16 -0400 References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: Safety wire Date: Thu, 31 Jul 2008 12:10:15 -0400 X-AOL-IP: 66.253.96.220 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: wrjjrs@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CAC13F0DDE532A_1594_EE6_webmail-nh12.sysops.aol.com" X-Mailer: AOL Webmail 38159-STANDARD Received: from 66.253.96.220 by webmail-nh12.sysops.aol.com (207.200.84.131) with HTTP (WebMailUI); Thu, 31 Jul 2008 12:10:15 -0400 Message-Id: <8CAC13F0D992E67-1594-787@webmail-nh12.sysops.aol.com> X-Spam-Flag:NO ----------MB_8CAC13F0DDE532A_1594_EE6_webmail-nh12.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii" Dale, I am a mechanical engineer by trade and do understand the difference, good call on your part. Truth is though that many socket head cap screws, aka allen screws, are case hardened, but in the head a good case hardening can result in through hardening. Semantics I know but either way it can be real tough on drills! Bill Jepson -----Original Message----- From: Dale Rogers To: Rotary motors in aircraft Sent: Wed, 30 Jul 2008 5:26 pm Subject: [FlyRotary] Re: Safety wire 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? >? >? ? --? Homepage: http://www.flyrotary.com/? Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html? ----------MB_8CAC13F0DDE532A_1594_EE6_webmail-nh12.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/html; charset="us-ascii" Dale,
I am a mechanical engineer by trade and do understand the difference, good call on your part. Truth is though that many socket head cap screws, aka allen screws, are case hardened, but in the head a good case hardening can result in through hardening. Semantics I know but either way it can be real tough on drills!
Bill Jepson


-----Original Message-----
From: Dale Rogers <dale.r@cox.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Wed, 30 Jul 2008 5:26 pm
Subject: [FlyRotary] Re: Safety wire

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 
> 
> 
 
-- 
Homepage: http://www.flyrotary.com/ 
Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html 
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