Jorge,
If this question is directed at me, no, I only use a bearing/bushing at the
top of the tower. I generally have at least 10 feet of mast (~3m) inside
the tower and I have always thought that the alignment issues with 2
bearings and a rotator was not worth any perceived benefit.
73,
geo - n4ua
On Fri, Dec 9, 2016 at 10:25 AM, Jorge Diez - CX6VM <cx6vm.jorge@gmail.com>
wrote:
> HELLO
>
> Did you use one of this on top of the tower or another one inside tower,
> between rotor and top of the tower?
>
> thanks,
> Jorge
>
> 2016-12-09 12:10 GMT-03:00 George Dubovsky <n4ua.va@gmail.com>:
>
>> >I would expect either
>> >tapered roller bearings, or today, do what most of industry does, and use
>> >an engineering plastic bearing.
>>
>> And, in fact, that's what I do. One mast has a brass shaft collar that
>> rides on a slab of Nylatron (GS grade I think), and the other mast uses a
>> scrap TB-3 that was machined to replace the ball assembly with a Nylatron
>> sleeve insert for axial and radial thrust. I expect both of them to
>> outlive
>> the towers they're sitting on... ;-).
>>
>> 73,
>>
>> geo - n4ua
>>
>>
>> On Fri, Dec 9, 2016 at 9:14 AM, <charlie@thegallos.com> wrote:
>>
>> > > Looks really well made. I had the original Rohn counterpart for years
>> > and
>> > > it just kept on going.
>> > > I added a zerk fitting so I could grease it. They last a very long
>> time
>> > > dry without lube, but I am anal
>> > > about lubing everything hihi.
>> > >
>> > >
>> > > Bob
>> > > K6UJ
>> >
>> >
>> > Looks nice, but one thing I just have not been able to understand for
>> years
>> >
>> > Tower thrust bearings are a LOW rotation speed, high load application,
>> > probably the WORST place to use ball bearings. I would expect either
>> > tapered roller bearings, or today, do what most of industry does, and
>> use
>> > an engineering plastic bearing. I mean, we don't need a torlon bearing
>> > there (the loads are NOT that high)
>> >
>> > I mean, a glass reinforced nylon, or a PTFE (Teflon) (say a 25% glass
>> > filled or molly filled) isn't going to cold flow at ALL under loads a 2"
>> > mast could sustain, will NEVER need lubrication, will never corrode etc
>> >
>> > You either get them molded for you (for some materials would be the
>> > cheapest way - you do NOT want to know what torlon costs), or you slice
>> it
>> > from tube, or you even just use end on rods set around the circumference
>> >
>> > I mean, today they run the pivot bearings and lower boom bearing on
>> cranes
>> > in plastic bearings, because they hold up better than metals in those
>> low
>> > rotation speed, intermittent rotation applications
>> >
>> > _______________________________________________
>> >
>> >
>> >
>> > _______________________________________________
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>> >
>> _______________________________________________
>>
>>
>>
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>>
>
>
>
> --
> 73,
> Jorge
> CX6VM/CW5W
>
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