[TowerTalk] Thrust bearing Help

Wed Nov 30 22:25:39 EST 2005

Jim,
On my thrust bearing (a ROHN TB-3 I think) I had a similar problem as it had
been locked in place for over 12 years!  It uses an Allen key type of bolt,
so after several applications of WD-40, I used a T-bar style Allen key to
open it.  It opened with a squeaky "pop" after I rocked it back a forth a
bit.
Now I keep the T-bar wrench up on the tower nested in a spare hole in the
flat top of the Rohn 25 tower top section and it is always ready and waiting
for use.
I do the same kind of thing with my van where I have a 1/2 inch ratchet
drive to raise and lower a 25 ft tubular tower on the van and a T-bar Allen
wrench for adjusting some permanently mounted Speed-Rail (TM) clamps also on
the van.

73,
Gordon Beattie, W2TTT
201.314.6964
w2ttt at arrl.net
w2ttt at att.com

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of K8RI on Tower talk
Sent: Wednesday, 30 November, 2005 17:46
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Thrust bearing Help

>I have a Glen Martin  TB-25 Thrust Bearing
>
>
>
> I am having trouble   BACKING OUT   the set screws that lock the Mast in
> place
>
>
>
> This TB-25 is made of Die cast Aluminum.
>
> I have used WD-40 and several other sprays.

As with most penetratiing oils, WD-40 may take a day or two to penetrate.
I noted one other reply on WD-40 being a water displacment oil.  Virtually 
all hydrocarbon oils displace water, but that is not how they break stuck 
bolts, and *pistons* free.

I'd give the WD-40 a number of applications and let it set for a day or two.

There are other penetrating oils available such as PB blaster and "Mouse 
Milk" (yes that is for real) and every one seems to have their favorite.

>
>
>
> I just can't break loose the bolts.  I just don't want to break the bolts 
> or
> the top housing of the TB-25.
>
There is probably some corosion in there between the aluminum casting and 
steel bolts.  If repeated applications of  penetrating oil do not work over 
several days (This problem requires patience) you can try alternating 
applications of heat to the casting around the bolt, applications of 
penetrating oil (careful of fire) and actually heating the bolt.  Remember 
the Aluminum has a far greater coefficent of expansion than steel.  Also try

working the pressure applied by the wrench to the bolt "back-and-forth" just

a little.

Another approach is an impact wrench set to very low power

Another, moving more toward last resorts is to tap the bolt head with a 
hammer in a direction that would drive it straight in.  When I say "tap", 
I'm guessing these are probably either 5/16" or 3/8" common steel rather 
than a grade 5 or 8 so they are already on the soft side. Based on that a 
"tap" is definately not a round house swing using a 5# Engineer's Hammer. 
<:-)) OTOH you can hit them fairly hard depending on the hardness of the 
bolt, the size of the bolt and the hardness of the mast inside the thrust 
bearing.
>
>
> Any ideas on what to spray on the bolts that will help break them loose

As I said earlier, this is a problem that normally takes patience. Although 
the process can be hurried with heat and impact, the hurrying often causes 
more problems than it solves.

As an example, we used to take small engines that had seized. You couldn't 
turn the crank with a pipe wrench, but take the head off, spray with WD-40, 
let set over night and you could turn the crank by hand the next day.

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com

>
>
>
> 73 de wb5aaa
>
> later,
>
> Jim Barron
>
>
>
>
>
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
> Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
> 
_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.

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