[TowerTalk] Nylok nuts

[Grant Saviers]

"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 at 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 at tm.net>,	<towertalk at contesting.com>
> Subject:	Re: [TowerTalk] Nylok nuts
> From:	"N2TK, Tony" <tony.kaz at 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 at contesting.com] On Behalf Of Roger
> (K8RI) on TT
> Sent: Thursday, July 06, 2017 3:58 AM
> To: towertalk at 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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