When I need a top plate radial bearing, I use black UHMW which is UV
resistant. 1, 2 or 4" thick depending on the load & 6" sq, bored 0.030"
oversize for the mast. HDG masts get a touch with a file to remove Zn
lumps & high spots. No thrust bearings are used, although the largest
has a collar in case PP rotator work is needed.
UHMW is the cheapest, is very slippery, and has decent PV and yield
specs. Whatever polymer is your favorite, make sure it is UV resistant.
Grant KZ1W
On 12/27/2020 10:12, Peter Voelpel wrote:
Yes, that´s what I use, Nylon or POM plates with a hole cut for the mast.
I also still use a thick bronze bearing on one tower.
All weight is on the rotator and I use another shelf above the rotator with
a temporarily muffler clamp above it if I need to remove the rotator.
https://pbase.com/df3kv/image/128881498
73
Peter
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Charles Gallo
Sent: Sonntag, 27. Dezember 2020 18:42
To: Grant Saviers
Cc: Tower Talk
Subject: Re: [TowerTalk] FW: FW: Thrust Bearing Installation
Every time this topic comes up, I alway think about “why are we doing this”?
“Thrust bearings” (agree, most are used as a second axial load bearing, not
thrust) in ham applications are, frankly low rotational speed, low
rotational duty application.
Always makes me think of the lessons learned when shipping cars by train
(fretting caused by vibration during non rotational times)
Frankly, what we have is the perfect place for solid bearings. In the old
days, bronze, today, plastic
I think a T shaped bearing, made of say a filled nylon, or filled acetal
would deal with 99% of the issues (never mind torlon/rulon etc). Industry
has gone to plastic bearings for low speed/low duty/ high load bearings for
a reason.
I don’t know how the Yaesu “thrust bearing” is made, but rotating one by
hand, they FEEL like plastic
--
73 de KG2V
Charlie
On Dec 27, 2020, at 12:02 PM, Grant Saviers <grants2@pacbell.net> wrote:
?Matt,
Got the image, thanks and nice work. Very informative about some of the
issues. The three bearing study would also help settle a lot of debates.
Were real bearing models developed? The design that was developed for
radial float (done in some machine tooling to float reamers) of the rotator
would be interesting.
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