Nyloc nuts - reuse or replace?

[KansasCityMilkman]

What's the general concensus on this?

Found the following article on Wikipedia :

"Authorities disagree on whether nyloc nuts should be reused. For example, Smith notes that the nylon insert is not damaged by installation and therefore they can be reused many times, Federal Aviation Administration Advisory Circular allows nuts to be reused if the prevailing torque is within specification. However, an United_States_Air_Force Air Force Technical Order requires replacement of self-locking nuts in critical areas.Various specifications for aerospace-grade self-locking nuts require that the running torque be maintained after a number of cycles of assembly, but without preloading the fastener.

[Andrew S]

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It depends on what you are securing and whether it is a safety issue or whether its on view.

Safety first, shiny nuts second

[DJT]

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With the price of the popular sizes being so cheap, it isn't going to break the bank by using new ones. Having said that, I have regularly re-used nyloc nuts over the past 30-odd years and never had one come undone as long as it has been torqued up correctly.

Thread lock fluid is also quite cheap and, if you were unsure about re-using a nylok nut, a dab of that would do the trick.

Dave

[Moraystag]

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Personaly if I consider that what ever is being secured is of a load bearing nature and more significantly is key to the safety and integrity of the user, change it out for new. It gives you peace of mind at the very least

[peterrc]

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Moraystag wrote:

Personaly if I consider that what ever is being secured is of a load bearing nature and more significantly is key to the safety and integrity of the user, change it out for new. It gives you peace of mind at the very least

Sounds like Stag paranoia to me. If the nut can be screwed on be hand past the nyloc insert discard it otherwise you can re-use it. If it makes you feel better and there is room for it use a spring washer.
Peter

[richardthestag]

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I have been known to reuse nylocs :PBUT only if

a) I don't have a shiney new one :dude:

b) the flats are not rounded :X

c) The original torque setting wasn't over 200ft/lbs which makes them use once as they canget a bit oval

d) I can't finger tighten it past the nylon bit :?

I then place the nut flat on the bench and give the nylon end a tap with my 3lb lump hammer. Tightens up real nice.

[DJT]

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richardthestag wrote:

I then place the nut flat on the bench and give the nylon end a tap with my 3lb lump hammer. Tightens up real nice.