[TowerTalk] US Tower bearing measurement needed

[DMartin560@aol.com]

Hi Roger and thanks for the reply,
This was exactly my original intent, but obtaining 2" OD tubing (if it's 
"pipe" it's measured inside diameter) on reasonably short notice was proving 
to be difficult.

A)  2" pipe is appx 2 1/4" OD  =  too big for thrust bearing
B)  1 1/2" pipe is appx 1 7/8" OD  =  1/8" too small, but may be able to use 
the set screws in the top support tube.

Additionally, it's 52 1/2" from top of thrust bearing to top of rotor shelf 
plus I need 24" out the top of the tower to mount the antenna.  With this 
length of tube/pipe with a plate welded on the bottom to bolt to the rotor 
shelf, I can't get this assy into the tower...I did not notice if the entire 
top plate would unbolt from the tower...if it does, I can go in from the top.

Like I said earlier, was originally going all the way down to the rotor 
shelf, as I took the measurement for pipe length and even traced a template 
of the holes in the rotor shelf and measured the ID of the thrust bearing.....

Will study on it a little more....
73
Dwayne   KG4ADM

<< Subj:     Re: [TowerTalk] US Tower bearing measurement needed
 Date:  05/01/2000 12:01:22 PM Eastern Daylight Time
 From:  -K9RB-@telocity.com (Roger Borowski)
 Reply-to:  K9RB@arrl.net (Roger Borowski)
 To:    DMartin560@aol.com
 
 Dwayne, Please consider my comments below in the spirit in which it is 
intended.
 I think you may want to rethink this a bit. I would suggest running the pipe
 through the thrust bearing and affix it with a pipe flange at the rotor 
plate,
 allowing the top section of the tower to absorb the bending moment of the
 extended mast/pipe and antenna. This is the intended design of use. Doing it
 this way, the worst thing that can occur is the mast/pipe bends just above 
the
 trust bearing surface.  It would seem that your proposal may rip the top 
bearing
 shelf loose in a heavy wind due to the long lever arm of the mast/pipe and
 weight of the assembly just bolted to the top bearing plate of the tower. A 
20+
 foot lever arm is not to be taken lightly! The forces and stress on those 
bolts,
 and the top plate in this case, are tremendous!  It would be possible to 
shear
 off your entire added assembly and have it fall, possibly doing serious 
damage
 and possible injury. I don't think it would be worth that gamble and since 
you
 say it is a "customer's" tower, you are opening yourself up for the 
liability of
 your "engineering" and installation. 73, -=Rog-K9RB=-
 ----- Original Message -----
 From: <DMartin560@aol.com>
 To: <K7LXC@aol.com>; <towertalk@contesting.com>
 Sent: Sunday, April 30, 2000 11:33 PM
 Subject: Re: [TowerTalk] US Tower bearing measurement needed
  >>

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