My thrust bearing has only two setscrews... at 90 deg to each other. That's
what led me to think that the thrust bearing is a weight-carrying device, to
take vertical load off the rotator. Many have told me the setscrews are for
centering the mast.... wouldn't that take 4 setscrews spaced 90 deg? or 3
at 120 deg? Jerry K3BZ
----- Original Message -----
From: "Phil - KB9CRY" <kb9cry@comcast.net>
To: "Jerry Keller" <k3bz@arrl.net>
Cc: <towertalk@contesting.com>
Sent: Monday, September 15, 2003 8:52 PM
Subject: Re: [TowerTalk] Thrust Bearing Question
>
>
> Jerry Keller wrote:
>
> >Do I understand correctly....that the thrust bearing (a) takes the weight
> >off the rotor, Not Really and (b) allows removal of the rotor while
leaving the mast
> >and antennas in place? Not Really again Any other purpose(s)?
> >
> >I have the good fortune to have a tiltover tower, so I can install
> >everything while it's horizontal, with no load on the mast. is 1/2"
enough
> >of a gap to leave in the mast-to-rotor connection? That's what I do.
> >
>
> >Do I then just tighten
> >the thrust bearing set-screws as tight as I can? The set screws only are
used
> >
> to center the mast in the bearing, they really can't hold any weight.
>
> >Or is there more to it? (My
> >thrust bearing didn't come with instructions, and I've never done this
> >before.)
> >
> >Jerry K3BZ
> >
> >
> >
>
> I have a 72 ft. tower with a 10 ft heavy wall mast, 5 ft in the tower
> and 5 ft above. On the mast is a KT34XA and a Ham IV rotator beneath.
> I set the mast in the rotator, bottoming it out. The rotator can handle
> the weight and many suggest some weight so the bearings in the rotator
> seat and wear evenly. The thrust bearing is on the tower top plate and
> the set screws merely center the mast withing the bearing. This is the
> setup without the antenna attached. Onto the mast, resting on the top
> of the thrust bearing is a stainless steel pipe clamp from McMaster
> Carr. This was firmly attached and then the antenna mounted onto the
> mast. So any additional weight from the antenna is partially borne by
> the thrust bearing. If I have to remove the rotator, which I have, I
> mount a screw jack on the top plate and use an extension block of wood
> to bear up onto the bottom of the antenna's boom to mast plate. As the
> mast and antenna are jacked up, I attach another clamp at the top of the
> bearing to hold the assembly up. I then attach a piece of Uni-strut,
> slotted steel channel to the mast below the top plate and up bolt it to
> the tower leg to hold the bottom of the mast in place. On my new tower
> I've mounted a second rotator plate beneath the top plate and above the
> rotator plate and this will serve this purpose. I must say that my
> assembly is rather simple since there is only the one antenna on the
> mast, etc. Capice? Phil KB9CRY
> _______________________________________________
>
> 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.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|