[Towertalk] Re: TB3 Set Screw

[Stan & Patricia Griffiths]

I have been out of town (Dayton, etc.) for a couple of weeks so this may
have been answered fully already.  Here goes anyway.

I have secured the TB3 bearing screw with another set screw which I
installed by drilling and tapping another hole in the aluminum bearing
mount.  The new set screw is aligned vertically and is installed from the
bottom of the bearing such that it holds the bearing screw firmily in place.
It is easy to remove if necessary.

Rohn's poor solution to movement of the bearing screw was to peen it in
place which holds only once and has to be redone if you ever remove it.
Adjustment of the bearing screw is critical.  If it is in too far, it binds
on the bearings as they try to roll past it.  If it is out too far, a
bearing can drop into the hole it leaves in the race and lock the bearing
tight.  The bearing screw can't fall out since it will come up against the
mast, but if it does, it is out far enough for a bearing to drop into the
hole and lock up.  The best way I have found to test for the best setting of
this screw is to hold the bearing with the mounting surface vertical, like a
wheel and with the bearing screw at the top.  You then spin the bearing and
if the hole is large enough to trap a bearing, gravity will help it happen.
You can adjust the bearing screw by turning it in until it touches a bearing
in the race and then backing it off just a little.  If it still binds, back
off a little more.  Then secure it in place with the second set screw you
installed.

I have given this suggestion to Rohn, but that is like talking to a stone
wall . . .

Stan
w7ni@easystreet.com

----- Original Message -----
From: "Mike Gilmer" <n2mg@eham.net>
To: <towertalk@contesting.com>
Cc: <jsbmjb@theriver.com>
Sent: Thursday, May 16, 2002 3:28 PM
Subject: [Towertalk] Re: TB3 Set Screw


> W7AG wrote:
> > Is it necessary to secure the TB3 set screw with loctite
> > before installing the bearing on the mast?
>
> It may not be necessary, but probably a good idea - and be sure to
> use "removable" threadlocker.  If you move/remove with that set screw,
> be sure you have re-installed properly - so there is no binding of the
> bearings.
>
> Mike N2MG
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