Julio:
The ID of my mast bearing is in fact the next size up from 2 inches. I
had originally purchased a 2 inch bearing but that was too small, so I
returned it and asked for the next larger size. I didn't measure it but it
could be 2-1/16.
73 de
Gene Smar AD3F
----- Original Message -----
From: <jperalta@tampabay.rr.com>
To: <ersmar@comcast.net>
Cc: "K8RI on Tower talk" <k8ri-tower@charter.net>;
<TOWERTALK@contesting.com>
Sent: Saturday, May 13, 2006 10:21 AM
Subject: Re: [TowerTalk] Thrust bearing shot
> This is very simular to the one UST uses. With the exception that the
> mast diameter is 2 1/16" and has a 2 hole bolt pattern. I wonder if
> the 2" hole would be too small for some masts?
>
> Julio, W4HY
>
>
> ----- Original Message -----
> From: ersmar@comcast.net
> Date: Friday, May 12, 2006 11:46 pm
> Subject: Re: [TowerTalk] Thrust bearing shot
> To: K8RI on Tower talk <k8ri-tower@charter.net>,
> TOWERTALK@contesting.com
>
>> Roger:
>>
>> I used a self-centering industrial bearing at the top of my
>> tower, similar to:
>> http://www.applied.com/catalog/ma/catalog.do?e=10&s=2000776&r=0 .
>> I lube it once each year with marine grease. It cost about what a
>> TB-3 would cost ($70 in 2001.) Because it's self-centering, it
>> will accommodate up to a +/- 2 degree misalignment of the mast and
>> bearing centerlines. FWIW.
>>
>> 73 de
>> Gene Smar AD3F
>>
>>
>> -------------- Original message ----------------------
>> From: "K8RI on Tower talk" <k8ri-tower@charter.net>
>> > I thought I'd pass on some information.
>> >
>> > It seems like even with care planning for problems when pushing
>> the limits
>> > the problems turn up where we don't expect them.
>> >
>> > I'm running a 97 foot ROHN 45G. The tribander is supported just
>> above the
>> > top of the tower on a 24' long, 2" structural steel tube with
>> 1/4 wall over
>> > an 1 1/2 tube with 1/4 inch wall made up of two sections
>> totaling about 44
>> > feet. So the center section has essentially a 1/2 inch wall,
>> supports the
>> > TH-5 at 100' while the 7L C3i 6 meter beam at 115' is mounted on
>> the 1 1/2
>> > pipe right at the top of the 2". The 144/440 array is 12 feet
>> above the
>> > 6-meter antenna at roughly 127'.
>> >
>> > The mast is supported by a TB-3 at the top of the tower with a
>> second TB-3
>> > about 12 feet below the top of the tower that just keeps the
>> mast centered
>> > with the rotator (PST-61) mounted at 17' below the top of the
> tower.
>> >
>> > I knew the leverage of the tall mast above the top of the tower
>> would create
>> > some pretty strong forces at the top of the tower, but after
>> about 4 years
>> > with lots of severe winds up here, the races in the TB-3 have
>> worn to the
>> > point where the upper race is setting right down on the washers
>> for the
>> > mounting bolts. This is causing the bearing to bind to the
>> point the PST-61
>> > is unable to turn the mast.
>> >
>> > It appears as if I'm going to need to replace the upper bearing
>> with a
>> > pillow block arrangement of some sort with a fairly close fit.
>> If it
>> > weren't for the massive side forces created by the leverage I'd
>> use oil
>> > soaked hard wood, but I think I'm going to need to get a split
>> block of
>> > steel or Aluminum machined to fit which will give a large
>> surface area to
>> > support the side forces without undue wear. I sure could use
>> that milling
>> > machine I was going to purchase before the market tanked back
>> around the
>> > turn of the century.
>> >
>> > And the day before I was going to order some LMR-600 and
>> fittings for the
>> > pigtails the price went up. <sheesh>
>> >
>> > Roger Halstead (K8RI and ARRL 40 year Life Member)
>> > N833R - World's oldest Debonair CD-2
>> > www.rogerhalstead.com
>> >
>> > _______________________________________________
>> >
>> >
>> >
>> > _______________________________________________
>> > TowerTalk mailing list
>> > TowerTalk@contesting.com
>> > http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
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>>
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