[TowerTalk] T2X rotor issue

[Jon Zaimes]

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/

 

Reviews of AA1K tower work on eham website:
http://www.eham.net/reviews/detail/12922

 

Hug your favorite tower every day, and always stay connected to it.