This is in reference to internally threaded aluminum products. Some years
ago, when I owned my first second-hand Volkswagen Beetle, the engine had
aluminum cylinder heads. Sometime during it's first ownership, someone had
over-tightened several spark plugs and damaged the internal threads in the
cylinder heads. I thought I'd need to replace both heads at considerable
cost. A mechanic told me about a simple device called a HELICOIL.
To prepare the damaged thread, a special oversized tap is used to clean out
the damaged aluminum and slightly enlarge the hole to accept the HELICOIL.
It's a stainless-steel spiral that screws into the prepared hole and
restores it to the original thread diameter and pitch. HELICOILS are
available in most common thread sizes. Matching oversize taps are also
available.
Ever since learning of HELICOILS, I began installing them in NEW aluminum
castings, before they became damaged. Adding a small amount of anti-seize
compound to the bolt threads will further ensure that the hardware can be
sufficiently tightened and then removed for maintenance in the future.
The most valuable advise that I can offer is to use a torque wrench when
fastening aluminum or magnesium components. Considering the number of
aluminum-encased rotors in use, I'd recommend that your local radio club
invest in an inexpensive torque wrench (Sears Craftsman) for use by it's
members. Between HELICOILS and torque wrenches, you will save yourselves a
lot of aggravation and money for new rotor housings...
73, Larry - W1GOR
>
To: <towertalk@contesting.com>
> Date: Thu, 20 Mar 2003 08:47:53 -0800
> From: "Dave Hough, W7GK" <w7gk@qsl.net>
> To: "Michael Hatzakis, Jr" <mike@hatzakis.net>
> Cc: towertalk@contesting.com
> Subject: Re: [TowerTalk] Yaesu vs. Hygain rotor
> Message-ID: <000b01c2ef00$7422ee80$43646464@host>
> References: <FHEDJEFBECLLBHNAOBOOKEHBCHAA.mike@hatzakis.net>
> Content-Type: text/plain;
> charset="Windows-1252"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 8bit
> Precedence: list
> Reply-To: "Dave Hough, W7GK" <w7gk@qsl.net>
> Message: 3
>
> Have both a Yaesu 800 and a Ham IV. The 800 turns a Cushcraft X7 and a 11
el. 2 mtr beam atop a 60' tower while the Ham IV turns a rotatable mast with
a stacked 4 el. 6m beam, a 11 el. 2m beam and a 11 el. 440 beam. Both rotors
work great. One thing to be cautious about the Yaesu is the bolt holes that
attach the rotor to the base plate are drilled and tapped into cast
aluminum. Aluminum is soft and the bolts have a tendency to strip the
threads if the bolts are overtightened, on the other hand if you
undertighten, the bolts work loose and fall out.
>
> Wish Yaesu had put steel nuts on the inside of the rotor housing.
>
>
> ----- Original Message -----
> From: "Michael Hatzakis, Jr" <mike@hatzakis.net>
> To: "Paul Henning" <paul@amtelco.com>
> Cc: "Contesting Lists" <towertalk@contesting.com>
> Sent: 19 March, 2003 14 31
> Subject: RE: [TowerTalk] Yaesu vs. Hygain rotor
>
>
> > thoughts about hygain HAM IV vs. Yaesu 800/1000 dxs?
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
> >
>
> ------------------------------
>
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>
> End of TowerTalk Digest, Vol 3, Issue 35
> ****************************************
|