John is correct about the commercial flange bearings. One flange bearing
option is a UCFL210-32. This is an industry standard 2" ID self-aligning
ball bearing in a cast iron 2-bolt flanged housing. They are available
through local bearing houses or online in the $50 price range. You can get
them with set screws or locking collars. They have held up well for me if
kept greased but rainwater can penetrate through the side shields and into
the bearing unit if allowed to pool from direct exposure. I have one that
has probably seen at least 20 years of service and still works fine. I use
white lithium based boat trailer wheel bearing grease in it. For rain
water protection I have tried a few different options but am now using
silicone roof jack clamped to the mast just above the bearing as a storm
collar. Also suggest to clean, prime, and paint the mounting side of the
flange if you decide to pursue this route. Otherwise, rainwater tends to
get up under the flange and galvanic corrosion can eat away metal at the
direct contact junction between the cast iron and the galvanizing on the top
plate. On the other exposed flange surfaces that can air dry between rain
storms, the iron just develops thin surface rust after the paint wears off.
Hope this info is helpful.
73
Matt
KM5VI
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of
john@kk9a.com
Sent: Wednesday, October 30, 2024 9:05 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 2" Thrust bearing With same bolt pattern , Rohn 45
The DX Engineering bearing does not cost much more than the Rohn TB3. I
have no experience with the DXE bearing but I did briefly own a Rohn bearing
and I quickly replaced due to its tightness. Replacing a bearing is a big
job if you have antennas on the mast so you really want a thrust bearing
that is going to last. Another commercial option is flange bearings but
you'll have to drill a couple of holes in the top plate. US towers uses
them and I believe they have very few issues if you keep them greased. You
can make one out of black Delrin, nylon, UHMW etc material, just drill holes
for the mast and mounting bolts. K3EJJ used to make nylon split bearings
that matched Rohn's hole pattern and they could be installed without
removing antennas however I have not seen them in long time.
John KK9A
Ed Stallman n5dg wrote:
I'm looking for a place to buy a 2" universal thrust bearing that will have
the same bolt pattern as the Rohn 45 flat top plate , I've had the bearings
seize on 3 Rohn bearing . I see DXE has a replacement but pricey . I think
it was here on Tower Talk , I seen links were I can buy the //universal
thrust bearing . Any suggestion is very welcome ./
/Thanks Ed N5DG
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