[Towertalk] 620/340

[K7LXC@aol.com]

In a message dated 4/14/02 6:03:16 AM Pacific Daylight Time, na4m@arrl.net 
writes:

> >     As far as the potential mechanical problems, double or triple-row the
>  >rivets per joint and they won't come apart. Make sure the element
>  >boom-to-element brackets are backed up with thru-bolts. And pay the extra 
> 10%
>  >for the upgraded 100 MPH version.
>  
>  Instead of double/triple-rowing the joint rivets why not use a couple of 
>  small stainless screws/bolts with appropriate lock washers and nuts or 
>  nylock nuts?     As matter of fact if there is a need to double/triple-row 
>  the rivets to prevent potential mechanical problems maybe rivets are not 
>  the best way to secure the joints - just use screws/bolts?   I know there 
>  are  many cases where pop-rivets are working just fine but to me they've 
>  always seemed kind of a dubious method to make secure reliable long-lived 
>  mechanical joints.

    The problem is that with the existing aluminum tolerances, there is 
enough room for the inner element piece to work against the rivets with the 
help of the wind. By putting in another off-setting row of rivets (or two), 
you remove the slop in the element joint and eliminate that problem. 

    The rivets aren't popping on their own so replacing them with another 
kind of fastener doesn't really accomplish anything. 

Cheers,
Steve     K7LXC
TOWER TECH -
Professional tower services for industry and amateurs