X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ccerelbas02.cce.hp.com ([161.114.21.105] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTPS id 2278815 for flyrotary@lancaironline.net; Wed, 22 Aug 2007 15:10:32 -0400 Received-SPF: none receiver=logan.com; client-ip=161.114.21.105; envelope-from=dale.r@cox.net Received: from ccerelint01.cce.cpqcorp.net (ccerelint01.cce.cpqcorp.net [16.110.74.103]) by ccerelbas02.cce.hp.com (Postfix) with ESMTP id 2E5BE35219 for ; Wed, 22 Aug 2007 14:09:40 -0500 (CDT) Received: from [16.83.194.73] (unknown [16.83.194.73]) by ccerelint01.cce.cpqcorp.net (Postfix) with ESMTP id D660A34152 for ; Wed, 22 Aug 2007 14:09:37 -0500 (CDT) Message-ID: <46CC89E3.7050009@cox.net> Date: Wed, 22 Aug 2007 12:09:23 -0700 From: Dale Rogers Reply-To: dale.r@cox.net User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Tap 'em holes was [FlyRotary] Throttle Body Nut Ideas References: In-Reply-To: Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit This machinist says: "Why would you want to *do* that?

Strictly speaking, cut threads - what you get from conventional taps -
are weaker than swaged threads, such as the rolled threads one usually
finds on AN class fastener.

So ... if one wants threads in alumin(i)um, one needs a tool that
displaces the metal, rather than cutting it. Eureka! Such a tool does
exist - the "fluteless thread forming tap" E.g.:

http://www.shoprutlandtool.com/webapp/wcs/stores/servlet/ProductDisplay;jsessionid=0000aUcDvp-FmIJrmRkZmUaWieP:-1?productId=27670&langId=-1&storeId=10001&catalogId=10001&parent_category_rn=

Rutland Tool # 21238428

Good hunting,
Dale R.
COZY MkIV #1254

Ernest Christley wrote:

Ed Anderson wrote:

Scott, I think the best answer is to simply tap those bolt holes for the thread size of your bolts. This does a number of things.

I've been told by a machinist that tapped holes in aluminum are weak. Any truth to that?

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