[TowerTalk] Bearings for Axial Load
grants2 at pacbell.net
Sun Jul 16 16:30:29 EDT 2017
TFE is very UV resistant. Promoted to replace glass on solar panels.
However, it is subject to significant mechanical creep. Early wire wrap
wire TFE insulation was known to "cut through" over time if routed too
tightly against a wire wrap post.
On 7/16/2017 7:43 AM, Jim Thomson wrote:
> 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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