[TowerTalk] T2X rotor issue

[K9MA]

As I recall, the T2X is concentric with a 2 1/16 inch mast. Use with a 2 
inch mast requires a 1/32 inch shim.

73,
Scott K9MA

On 7/3/2020 19:42, Robert Harmon wrote:
> Jon,
>
> I have had a number of T2X rotators over the years and they all worked nicely with 2" OD mast.  Thats a strange situation
> with your unit.   It will be interesting to hear if others have had this issue.  I am taking an old unit out of service next week
> for overhaul.  I will see what I find on the ears.
>
>
> 73,
> Bob
> K6UJ
>
>
>
>> On Jul 3, 2020, at 4:47 PM, Jon Zaimes via TowerTalk <towertalk at contesting.com> wrote:
>>
>> In preparing a mast for a new Rohn 55 tower here, I pulled a spare T2X
>> (HyGain Tailtwister) rotor off the shelf. It had been rebuilt in 2016 and
>> kept for a spare.
>>
>>
>>
>> With the rotor horizontal on the workbench, I took a short piece of 2" OD
>> galvanized steel Rohn mast and set it into the V area in the upper mast
>> housing. Much to my surprise, it would not completely seat in the V. The
>> "ears" around the four U bolt holes were large enough to prevent full
>> insertion of the mast. This was obvious if I tried to slide the mast in on
>> the V from the upper end - it stopped as soon as it came to the upper set of
>> ears.
>>
>>
>>
>> Of course, with the mast not seating in the V completely it is not
>> concentric with the rotor and risks damage to the housing or motor.
>>
>>
>>
>> This rotor is stamped 1993 on the bottom but it's unknown if the upper
>> housing is that old or was replaced during the most recent or a previous
>> rebuild. I bought it used.
>>
>>
>>
>> I pulled an older  T2X off the shelf (circa 1984) and noticed that the
>> "ears" on this one were different - nice and square while the 1993 model had
>> rounded corners on these ears. The mast easily fit into the V on the older
>> model, with room to spare: I slid a thin piece of aluminum flashing down
>> between the mast and ear on each side.
>>
>>
>>
>> My quick fix on the problem housing will be to file and grind the ears back
>> enough so the mast can fully seat in the V.
>>
>>
>>
>> But I'm wondering if this is a common issue. It might not be easily
>> discovered up on the tower, unless a climber were looking from the back and
>> down and noticed the gap between V and mast.
>>
>>
>>
>> I have a half dozen T2X in service on my own towers, and have worked on
>> dozens and dozens of others, but this is the first one with this fit problem
>> observed.
>>
>>
>>
>> I did verify the mast piece I was using was truly round (not compressed) and
>> was 2" OD. The T2X is in fact specified to take a mast up to 2 1/16" OD.
>>
>>
>>
>> On the '93 model, I was able to easily insert fully a piece of 1.9" OD water
>> pipe, often used for light load mast material. This fit in the V just fine.
>>
>>
>>
>> 73/Jon
>>
>>
>>
>> Jon P. Zaimes, AA1K
>>
>> Tower climber for hire
>>
>> http://www.aa1k.us/
>>
>>
>>

-- 
Scott  K9MA

k9ma at sdellington.us