"Nylok" used generically doesn't mean much re the actual
specifications. Nylon is available in several UV resistant types and
"virgin" UV is not UV resistant. In general, colors, the darker the
better, are a good indicator but there are also additives (like suntan
lotion chemicals) that don't color the nylon. For a mind boggling
choice of "nyloks" see
http://catalog.continental-aero.com/category/all-categories My nylok
collection also includes Mil-Spec ones that use inserts other than nylon.
I suspect, but haven't found specs to prove it, that most commercial
grade nyloks now use UV resistant nylon. I buy all of mine from
McMaster and have never had an insert fail or seen a failure in an
experienced antenna I've acquired. OTOH, to be extra secure, I put the
nuts on the underside of parts as much as possible. Loctite is messy
but another choice. I use Nord-Lock washers for high vibration or
"can't loosen" applications when full bolt tension is ok, as split
ring lockwashers are nearly useless. There are many many choices for
fastener locking technologies. for some of them check out
https://www.mcmaster.com/#hex-locknuts/=18dpj92
One of the best means to prevent nuts from loosening is to torque to the
rated value for the fastener, thus developing the most friction
resistance in the threads to it loosening. Structural bolts (A325
grade) are torqued to arm breaking values and have no locking devices
(minimum 350 ft-lbs at 3/4" dia)
Since a lot of antenna bolts are through thin wall tubing where the
fastener is much stronger than the crush resistance of the assembly, and
it is likely that some day it will be taken apart, I'll keep using nyloks.
Grant KZ1W
On 7/6/2017 5:20 AM, john@kk9a.com wrote:
I have heard professional ham tower guys complain also about them. I have
used them in locations with much more UV than MI and have not noticed any
issues however none of mine point up. I do not purposely buy Nylok nuts
because they are harder to assemble however if they are included with a
purchased item, such as DX Engineering element brackets, I use them.
John KK9A
To: "'Roger \(K8RI\) on TT'"
<K8RI-on-TowerTalk@tm.net>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] Nylok nuts
From: "N2TK, Tony" <tony.kaz@verizon.net>
Date: Thu, 6 Jul 2017 06:12:15 -0400
Roger,
That is weird. Checked a can of old Nyloks that had been outside for years.
The nylon insert looked fine. Been using Nyloks for years without that issue
up to 5/8". Except for the tower (Rohn galvanized) itself and the rotator to
mast clamps (plated #8 hardened bolts so I can really crank down on them),
all hardware including u-bolts are SS using Nyloks with anti-seize. No lock
washers. I just use flat washers. Never had a nut loosen after 24 years. I
do not reuse Nyloks, just in case.
73,
N2TK, Tony
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Roger
(K8RI) on TT
Sent: Thursday, July 06, 2017 3:58 AM
To: towertalk@contesting.com
Subject: [TowerTalk] Nylok nuts
Nylok nuts do not last around here. I thought it was UV, but many have told
me that Nylon is impervious, or resistant to UV. I had based my thoughts
that the nuts oriented so the nylon was up were the first to go. The nylon
virtually disappeared out of them, so I finally gave up on them.
73
Roger (K8RI)
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