X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from yw-out-2324.google.com ([74.125.46.31] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3553945 for flyrotary@lancaironline.net; Fri, 20 Mar 2009 12:45:51 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.46.31; envelope-from=lehanover@gmail.com Received: by yw-out-2324.google.com with SMTP id 5so832083ywh.7 for ; Fri, 20 Mar 2009 09:45:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:message-id:subject :from:to:content-type; bh=6fikrL11DQgkBt3HnlFDmMxq8OofSakzOWtBs2g0IzE=; b=MDgmNsKX4QdsIAkl8OtjwbtRRdSNb0w6zhYexLInAsxqNfXJFwDije31wnx1qNEuVY iiaSf4ckDejum/dR9vNJqlY7GP6Uobkgg2HRK65aS4/4/Bsl3X9+zu9QkNJAGQ+TP8+2 49YTJOt7l3DcNKhB4bezuLeE6UIG8UkhzddKU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=d2x/dvwg8TwCUgdcTOUTtsLPIBZZNlxTgZNooAuQZDlYEtnc6wIIdCc+AqOH4ZJlcx hbbFnmYT7yzmGJrxuaLDRXqyTdkFjrmG27BvfGCdH08xATgnyejmx6TK/m98b9k3B9HI UYwFiBpBLDEiJv+wW4yRMYyKN/aA9I3r3+mXg= MIME-Version: 1.0 Received: by 10.231.10.140 with SMTP id p12mr903645ibp.38.1237567513885; Fri, 20 Mar 2009 09:45:13 -0700 (PDT) Date: Fri, 20 Mar 2009 09:45:13 -0700 Message-ID: <1ab24f410903200945x49475bfdnd8d6b6476b11c0b4@mail.gmail.com> Subject: Aluminum hole repair From: Lynn Hanover To: flyrotary@lancaironline.net Content-Type: multipart/alternative; boundary=00221532c7180cfbfa04658fa490 --00221532c7180cfbfa04658fa490 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Thanks Ed, yes I have a tail-dragger and situation is as you stated =85 wil= l reconsider the gasket. I have a new tube of Ultra-Grey. Any comments on the aluminum Front Cover thread repair? Jeff (For blind holes). Where practical, tapping out to 1/4" 20 can be used. Or for the purest, a Helicoil in metric. (For holes where the back of the hole will be exposed if it were deeper) If you have a TIG machine, build up behind the damaged hole (inside the cover) flycut the upper end of the hole open. Slip in a metric nut covered with epoxy, tension the nut with with a scew dipped in oil with the excess blown off, and let the epoxy set up. (For holes where the upper end is clearly open) Flycut or die grind a flat above the threaded end and just use a nut and a stud. Tension the stud and nut with another nut and epoxy the stud and nut in place. You could also TIG the hole shut, redrill and retap. Aluminum is not good at holding onto small diameter screw threads, as you may have noticed. The metric screw threads are just a bit too fine, and can be over torqued with no difficulty. Larger diameter course threads work better. Course threaded studs are best because they eliminate the wear problem of the the screw going into and out of the aluminum hole. This is also why nutserts steel liners and helicoils are better. There wear is between the screw and the steel hole liner. If the engine is being held into the airplane by just the oil pan screws, I would go over sized on all of them. All studs, epoxied in place. Course threads in the engine and fine threads through the mounting plate. I have had to repair many front covers. If you weld on one, bolt it to a front iron, as they are very flexible. I can make drawings if anyone needs them. Lynn E. Hanover --00221532c7180cfbfa04658fa490 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable

Thanks Ed, yes I have a ta= il-dragger and situation is as you stated =85 will reconsider the gasket.

I have a new tube of Ultra= -Grey.

Any comments on the alumin= um Front Cover thread repair?

Jeff
=A0
=A0
=A0
=A0(For blind holes).
=A0
Where practical, tapping= out to 1/4" 20 can be used. Or for the purest, a Helicoil in metric.<= /span>
=A0
=A0
(For holes where the bac= k of the hole will be exposed if it were deeper)
=A0
If you have a TIG machin= e, build up behind the damaged hole (inside the cover) flycut the upper end= of the hole open. Slip in a metric nut covered with epoxy, tension the nut= with with a=A0scew dipped in oil with the excess blown off, and let= the epoxy set up.
=A0
(For holes where the upper end is clearly open)
=A0
Flycut or die grind a flat above the threaded end = and just use a nut and a stud. Tension the stud and nut with another nut an= d epoxy the stud and nut in place.
=A0
You could also TIG the hole shut, redrill and reta= p.
=A0
Aluminum is not good at holding onto small diamete= r screw threads, as you may have noticed. The metric screw threads are just= a bit too fine, and can be over torqued with no difficulty. Larger diamete= r course threads work better. Course threaded studs are best because they e= liminate the wear problem of the the screw going into and out of the alumin= um hole. This is also why nutserts steel liners and helicoils are better. T= here wear is between the screw and the steel hole liner.=A0
=A0
If the engine is being held into the airplane by j= ust the oil pan screws, I would go over sized on all of them. All studs, ep= oxied in place. Course threads in the engine and fine threads through the m= ounting plate.
=A0
I have had to repair many front covers. If you wel= d on one, bolt it to a front iron, as they are very flexible.
=A0
I can make drawings if anyone needs them.
=A0
Lynn E. Hanover
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