[TowerTalk] Bearings for Axial Load

Jim Thomson jim.thom at telus.net
Sun Jul 16 10:43:34 EDT 2017

Date: Sat, 15 Jul 2017 20:27:49 -0700
From: Grant Saviers <grants2 at pacbell.net>
To: "Roger (K8RI) on TT" <K8RI-on-TowerTalk at tm.net>,
towertalk at contesting.com
Subject: Re: [TowerTalk] Bearings for Axial Load

<The spherical dual roller bearing described in the post that started the 
<thread is designed to accommodate significant shaft angular 
<misalignment.  That would occur when the tower leans in strong wind.  
<They are not intended to come apart and the preload/clearance is 
<established in the precise grinding of the parts.
<Grant KZ1W

##  UST uses a peer brand bearing..at each end of the main drum, that allows for
angular shaft misalignment.   On the drum, its all a radial load.  The peer bearingS, used by
UST for the mast, are not of that type, and are not designed for angular shaft misalignment. 

##  However, I have see the bearings, designed for angular shaft misalignment, used on masts.
You can spot these types quickly, they resemble a normal  2 or 4 mounting hole pillow block bearing,
but the hollow shaft in the middle, will....wobulate, and tilt a few degrees in any direction off the main axis.   

##  I tried uhmw sheeting, .125 thick, for some hb  2 inch diam disc insulators on a 40m yagi a few yrs ago.  They were slid
over the normal  solid insulator...and positioned dead center in the solid insulator.  The idea was to  increase the
V breakdown of the solid insulator.   Works.... but the white UHMW  turned brittle after 1-2 years..and was very fragile.
It was not UV resistant.   I have a lot of teflon on hand....is teflon UV resistant ?? 

Jim   VE7RF 

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