[TowerTalk] Fwd: Lockwasher Comparison

Fri Jul 29 08:12:16 EDT 2016

I can't stand the new dimpled nuts that Rohn has gone to on towers. I sent 
them back and found a place to get the older ones with standard nuts. I've 
never ever had a nut come off of a Rohn tower leg (horizontal bolt as used 
in G series). ALL of the load is vertical. There's no reason for the nuts to 
ever come off. Also there is enough galvanizing on their bolts that even the 
standard nuts take a bit of force to install. On the new ones I literally 
could not get the nut on one of the bolts - it went about 1/2 way and 
froze - not even a very large wrench would do it. The other 5 were all VERY 
difficult. That to me is an example of over-reacting to someone's failure to 
install the proper hardware.

As for the guy that had one fall out - I'd guess he wasn't using Rohn 
galvanized bolts and nuts or they were used and re-used. New ones have 
plenty of galvanizing to keep the nut in place when tightened sufficiently 
to the leg.

Gary
K9RX

-----Original Message----- 
From: Hans Hammarquist
Sent: Friday, July 29, 2016 12:09 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Fwd: Lockwasher Comparison

When I put up my tower, the sections were bolted together with a special 
self locking nut. The nuts had three dents in them and there were friction 
that made it necessary to use a wrench to put them in place. The tower 
doesn't shake or vibrate that much but I have a tough time to imagine these 
nut will unscrew themselves.

Anyone else with experience with these kind of lock nuts?

Hans - N2JFS

-----Original Message-----
From: Roger (K8RI) on TT <K8RI-on-TowerTalk at tm.net>
To: towertalk <towertalk at contesting.com>
Sent: Thu, Jul 28, 2016 10:31 pm
Subject: Re: [TowerTalk] Lockwasher Comparison

There are Helicoil steel thread replacement inserts that work really
well and were inexpensive the last time I used them.

Others like Nordlocks, while I've had very bad luck with them.  We are
nowhere near being downwind from industrial centers with the Chicago
area at near 200 miles, but the Nylon inserts just seem to dissolve away
in a year or two. None have made it past two years. I'd like them if
they'd last, but here? They are short term only. If the threads are shot
a bolt through from the inside with the head epoxied in place has worked
for me as a stud. The mount to accessory plate is not precision and
there are usually enough threads left to screw the bolt through.

I can find no reason for their short life. I thought it was IR as nylon
rope breaks down and gets stiff out in the weather, but others in areas
with far more sunshine than we have said they had no problems.

I'd advise drilling a small drain hole, but not large enough for
Muddobbers to get in. They ruined the matching network on an AV640 for me.

The SS bolt with NordLock nuts would be ideal if I could get them to last.

73

Roger (K8RI)

On 7/28/2016 Thursday 3:48 AM, Ian White wrote:
> Grant KZ1W wrote:
>
>> Another place I use Nordlocks is for rotator base bolts.  Since
> aluminum
>> has about 2x the expansion per degree F as steel (alloys and temper
> make
>> big differences), there is temperature cycling of the bolt load.  It is
>> also the case that I don't want to mess with Loctited bolts when on the
>> tower, but with the cautions, it works. Used rotators I've bought
> always
>> seem to have roughed up base threads, and a Helicoil insert is the
>> ultimate fix, since they are stronger than the raw aluminum threads.
>>
> If the threads in aluminium rotator castings aren't too badly damaged, a
> simple alternative is to use RED Loctite to fix short threaded studs
> permanently into the rotator base. (Even better, insert set-screws from
> inside the base casting to leave protruding studs, and again use Red
> Loctite.) During installation, the studs pass through the holes in the
> tower plate, locating the rotator safely in its correct position even
> before you add the nuts and washers.
>
>> Nylocks everywhere else.
> Make that NEW Nylocs, every time.
>
> Threaded studding can also be used to rescue damaged threads in the bell
> casting on Ham-IV and similar rotators. Again, clean out the threads and
> insert stainless steel studs, fixed permanently in place using Red
> Loctite. Then use Nyloc nuts to secure the two castings together.
> (Because the original self-tapping screws cause corrosion damage in the
> aluminium casting, you may need to re-tap the holes to a slightly larger
> size. Although you may lose some thread engagement, the Red Loctite will
> help fill the gaps.)
>
>
> 73 from Ian GM3SEK
>
>
> _______________________________________________
>
>
>
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-- 

73

Roger (K8RI)

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