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Re: [TowerTalk] Ham Antenna Rotator: The Teardown

To: Mike Lucas <w5chr@bellsouth.net>
Subject: Re: [TowerTalk] Ham Antenna Rotator: The Teardown
From: Jim Rhodes <jimk0xu@gmail.com>
Reply-to: jim@rhodesend.net
Date: Tue, 4 Dec 2018 06:42:36 -0600
List-post: <mailto:towertalk@contesting.com>
Yes, that is another thing I have always done, ever since the first time I
struggled with getting bolts and holes aligned. Never again, just drop the
rotor into the holes and put the nuts & washers on.

Jim Rhodes
K0XU

On Mon, Dec 3, 2018, 14:47 Mike Lucas <w5chr@bellsouth.net wrote:

>
>        When rebuilding a Ham-M style rotor, studs can be used in place
> of the 1/4-20 bolts from the factory. There is room to increase the size
> to 5/16-18, and to use a better grade material at the same time.
> Grainger sells a bag of 10 pieces of 5/16-18 type 316SS studs at a
> reasonable price. Grainger part number 21 YN26. Drill the (4)  bolt
> holes to 1/4 inch, to the bottom of the hole. Tap the re-drilled holes
> to 5/16-18 thread. Use a suitable lube when drilling and tapping.
> Kerosene is usually the choice of us older machinists.
>          Clean the gorp out of the threaded holes. Install the studs to
> the bottom of the tapped hole. Two 5/16 nuts jammed together will allow
> the stud to be bottomed out in the threads. Use Loctite on the stud end
> in the rotor housing only, nowhere else. Un-jam the two nuts used to
> install the stud, and tighten the bottom nut against the case for a jam
> nut.
>           Repeat the above for three other studs. Be careful where the
> Loctite is used!.
>
>            With the case turned to it's upright , normal position, use a
> combination of nuts and flat washers  to mount the rotor to the tower
> plate. By using the full four inch length of the studs, the bottom
> surface of the case will be about 2-1/2 inches above the rotor plate.
>            From the top down, the sequence is : (1) nut (2) nut (3) flat
> washer (4)rotor plate (5) flat washer  (6) nut  (7) nut. If regular low
> carbon nuts are used, they won't gall on the stud. With the rotor
> elevated, the cable is easily routed, the rotor can be lowered for
> clearance to slip it out of the mast, all sorts of good things.  Jam
> nuts keep everything where it belongs. This is a quick and dirty how-to,
> but it works. I have installed studs in a rotor mounted in a TX455
> standing upright.
>
>            Mike W5CHR
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