[Towertalk] Preventing Loose Rotor Bolts

[K7LXC@aol.com]

In a message dated 4/25/02 12:49:49 PM Pacific Daylight Time, 
jsbmjb@theriver.com writes:

> 1.  What thrust bearing brand is the most reliable in a high wind (i.e.
>  lots of movement and vibration) environment?
>  
    The de facto TB standard is the Rohn TB-3 for 2" masts. It doesn't need 
any grease but the aluminum bearing races can take a beating from the mast 
movement.
>   
>  2.  If two thrust bearings are used, what is the minimum recommended
>  spacing between them?
>  
    Please do not use two TB's. The rotator plate, rotator, mast clamp, and 
top plate are not precision pieces of hardware. The cumulative tolerances can 
be fairly dramatic. Using two TB's means that you're just increasing the 
chances of having bind in the system when being rotated. 

    The middle plate by itself is fine because all you're trying to do is 
keep the top heavy mast basically vertical when you have to do a rotator 
swap. The 2nd TB is unnecessary. 
>   
>  3.  How difficult is it to align one or two bearings with the rotor?
>  
    See above. Don't bother. 
>   
>  4.  Do the comments about Loctite or safety wiring the bolts apply to
>  the thrust bearing bolts also?
>  
    Not really. They are really big nuts and bolts and the TB only turns at 1 
RPM so the stresses are relatively minor. 

Cheers,
Steve     K7LXC
TOWER TECH -
Professional tower services