A hint for reusing self tapping bolts without reaming out the hole.
When reinserting self tapping bolts, apply a light pressure and *slowly*
turn them the wrong way (as if you were unscrewing them). You will hear a
click and the bolt will drop forward a tiny bit. With practice you can even
feel it drop. As soon as the bolt clicks or drops you can turn it back in.
If you fel resistance, stop immediately and again turn it out until you
hear, or feel the click. (you may need to repeat the operation a couple of
times to actually find the existing threads) It will use the original
threads without cutting new ones or removing much, if any metal.
Electricians use this trick on electrical panels to prevent the screws from
becoming useless.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
----- Original Message -----
From: "David Hachadorian" <k6ll@adelphia.net>
To: "Towertalk Reflector" <towertalk@contesting.com>
Sent: Saturday, April 16, 2005 4:00 PM
Subject: Re: [TowerTalk] Rotor disassembly
>
> ----- Original Message -----
> From: "Dick Burke" <k7rb@tantella.com>
> To: <towertalk@contesting.com>
> Sent: Saturday, April 16, 2005 6:48 AM
> Subject: [TowerTalk] Rotor disassembly
>
>
>> Hi,
>>
>> I'm trying to refurbish a very old Ham-M rotor. The previous owner
>> managed to remove one of the 4 bolts holding the housing halves
>> together
>> and torqued the heads off two others. I managed to torque the head
>> off
>> the remaining bolt.
>
> I'll bet someone used permanent Loctite on those bolts. I think you
> should buy a new upper housing. It's not a bad idea to buy that
> housing anyway, because those four bolts are self-tapping and manage
> to ream out a little aluminum each time they are removed. After a few
> disassembly cycles, the bolts start unscrewing themselves up on the
> tower, which produces an embarrassing failure mode, with the antenna
> spinning in the wind, and the lower (brake) housing sitting directly
> on the rotor shelf!
>
>
> It seems like the two halves of the housing should
>> come apart now but I've been bathing it with WD-40 for a couple
>> weeks
>> and banging on the housing with a hammer, but can't get the two
>> halves
>> to separate. They must be really corroded together.
>>
>> I've also managed to break a couple of screw extractors trying the
>> get
>> the headless bolts out.
>
> Maybe the screw heads didn't break off completely? Anyway, once you've
> make the decision to buy a new upper housing, you can attack the old
> one in a destructive manner. It's only aluminum. You'll get it apart.
> How about putting a nail set on one of those broken screws and giving
> it a big whap with a hammer?
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
> _______________________________________________
>
> 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
>
_______________________________________________
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.
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