X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 25 Nov 2013 08:09:40 -0500 Message-ID: X-Original-Return-Path: Received: from rc5-smtp.comporium.net ([208.104.2.19] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTP id 6612939 for lml@lancaironline.net; Mon, 25 Nov 2013 06:41:52 -0500 Received-SPF: pass receiver=logan.com; client-ip=208.104.2.19; envelope-from=snopercod@comporium.net Received: from rg25.comporium.net ([208.104.244.60]) by rc5-smtp.comporium.net ({548c1f54-a96b-4a18-a171-d2818e6ccf4d}) via TCP (outbound) with ESMTP id 20131125114116623; Mon, 25 Nov 2013 11:41:16 +0000 X-RC-FROM: Received: from 33.225.235.68.dsl.brvdnc.dynamic.citcom.Net (EHLO _127.0.0.1_) ([68.235.225.33]) by rg24.comporium.net (MOS 4.3.4-GA FastPath queued) with ESMTP id PLX74859 (AUTH snopercod); Mon, 25 Nov 2013 06:41:16 -0500 (EST) X-Original-Message-ID: <5293375A.1050308@comporium.net> X-Original-Date: Mon, 25 Nov 2013 06:41:14 -0500 From: John Cooper User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.1.1 MIME-Version: 1.0 X-Original-To: bob mackey , lml@lancaironline.net Subject: Re: [LNC2] Lycoming Exhaust Flange Nuts References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------000804080905020005030903" X-MAG-OUTBOUND: comporium.redcondor.net@208.104.244.48/28 This is a multi-part message in MIME format. --------------000804080905020005030903 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Bob-- Thanks for all that, especially the timely warning on the stainless steel nuts; I haven't installed them yet so I'll use the chrome-moly nuts instead.I had planned to use anti-sieze compound on the studs, but that probably would have just burned off. --John On 11/25/2013 3:09 AM, bob mackey wrote: > I also switched to 12-point reduced diameter "K-nuts" for my Lycoming > exhaust. > However, I would strongly advise against using stainless steel. It > will gall and weld to the stud, then the stud will come out with the > nut. If you're lucky. If not so lucky, the stud will break off. > > I used a black-oxide chrome-moly steel flange locknut from the > aviation department at McMaster Carr. > Part Number 90759A200 > > Chrome-Moly Alloy Steel 12-Point Flange Nut, Black-Oxide, 5/16"-18 > Thread Size > http://www.mcmaster.com/#nuts/=pj23uv > > Before I switched to the 12-point nuts, I used a 1/4 drive socket > ground down to fit into the space. the socket depth was cut down so > that it just engaged the top 1/8" of the 1/2" hex nut. > BTW "standard" 5/16-18 hex nuts fit a 1/2" wrench. If your nuts need a > 9/16" wrench, they are "heavy" nuts. --------------000804080905020005030903 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit
Bob--

Thanks for all that, especially the timely warning on the stainless steel nuts; I haven't installed them yet so I'll use the chrome-moly nuts instead.I had planned to use anti-sieze compound on the studs, but that probably would have just burned off.

--John

On 11/25/2013 3:09 AM, bob mackey wrote:
I also switched to 12-point reduced diameter "K-nuts" for my Lycoming exhaust. 
However, I would strongly advise against using stainless steel. It will gall and weld to the stud, then the stud will come out with the nut. If you're lucky. If not so lucky, the stud will break off. 

I used a black-oxide chrome-moly steel flange locknut from the aviation department at McMaster Carr. 
Part Number 90759A200
Chrome-Moly Alloy Steel 12-Point Flange Nut, Black-Oxide, 5/16"-18 Thread Size

Before I switched to the 12-point nuts, I used a 1/4 drive socket ground down to fit into the space. the socket depth was cut down so that it just engaged the top 1/8" of the 1/2" hex nut. 
BTW "standard" 5/16-18 hex nuts fit a 1/2" wrench. If your nuts need a 9/16" wrench, they are "heavy" nuts. 

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