"One-time" nuts - Should I care?

[ChrisGreaves]

I have taken delivery of a horizontal-shaft wind turbine; the three blades are to be bolted on with the supplied bolts and nuts, and the nuts are "one-time only".
I suppose that there is some neat design feature that will not allow the nuts to be re-used should one want to remove and then replace the blades.
I suppose too that there is some legal liability if a blade dismounts in a 164Km/hr (45m/s) wind gust ...
The turbine is "rated" to 40m/s.

For various reasons I want to be able to dis-assemble the system into its component parts (turbine, converter, battery, applications) and then re-assemble. Twenty-inch blades might be susceptible to damage if they remain bolted to the hub.

Might one or more of you enlighten me as to the what and why of one-time nuts?

20210607_160153a.jpg

The blue thing is a thin rubbery sort of washer, from what I can see/feel.

It seems to me that what I have here is a nut and bolt, available at your local hardware store. I mean, if I remove the nut and it crumbles into dust, I just use a store-bought nut and bolt, right?

Thanks for any pointers
Chris

[HansV]

Eileen's Lounge is home to many full-time nuts. I'm not sure it's the best place to ask about one-time nuts...

[Leif]

I think that is what is known as a Nyloc nut. My understanding is that the blue insert is nylon which creates high friction as you have to cut a thread into it, and this prevents the nut from becoming loose.

If you reuse them, the nylon insert will not lock as well as when first used, hence the term "one time only".

If you do take it all apart, I would recommend replacing them for security, and avoid the possibility of a blade detaching at speed and you ending up with chopped nuts.

[jstevens]

Chris,

Leif is spot on.

Since you're working with a horizontal-shaft wind turbine there will be vibration impacting the nuts. Replacing them makes sense otherwise stand back and watch it take off. Since you like to bake, you could put the chopped nuts to another use.

A quick online search for Nylon nuts resulted in a package of 25 for $7 USD depending on the thread size.

[BobH]

They serve the function once served by lock washers. Some of us nuts got tired of trying to keep a supply of all sizes of lock washers.

[Leif]

They can also be used where a lock washer can not - e.g. if you want something to swivel or rotate but still have the nut firmly fixed to the screw/bolt.

[John Gray]

I think that is what is known as a Nyloc nut. My understanding is that the blue insert is nylon which creates high friction as you have to cut a thread into it, and this prevents the nut from becoming loose.

And there was me thinking that the blue colour indicated that Chris had been presented with USB 3 nuts!

[ChrisGreaves]

I think that is what is known as a Nyloc nut. My understanding is that the blue insert is nylon which creates high friction as you have to cut a thread into it, and this prevents the nut from becoming loose.If you reuse them, the nylon insert will not lock as well as when first used, hence the term "one time only". If you do take it all apart, I would recommend replacing them for security, and avoid the possibility of a blade detaching at speed and you ending up with chopped nuts.

Thank you, Leif. I had seen 'Nyloc' in my browsing; this all makes sense. I see a later reply that mentions lock-nuts, which we used on Meccano set cranes etc. when I was eight. So I have a set of regular bolts with regular nuts, should I choose to replace them.

I do recall from a brief stint working for an aircraft mechanic, or on a farm, bolts with threads that went in the opposite(?) direction of the shaft rotation so that the nuts couldn't work their way loose/off; but then some sort of locking wire (through the bolt/) was used, too.

It's true, then: the general population IS reduced in intelligence and competence, so that we have to have plastic-with-everything because we can't wield two spanners at the same time; the other hand is holding a smart phone so we can watch a DIY on YouTube..
Either that, or the industry has worked out how to trick consumers into buying higher-priced items that are "not re-usable". Whoulda'thought!!

Thanks
Chris

[ChrisGreaves]

A quick online search for Nylon nuts resulted in a package of 25 for $7 USD depending on the thread size.

Thank you John.
From my point of view, it's off to Swyers hardware (or Durdles) on my $40 bike; nuts and bolts are sold piece by piece here, so six bolts and twelve shiny nuts later I will be set up.
Six nuts, when I think about it. Those original six nuts still work; I need six extra nuts and then six longer bolts.

The pedant in me says that longer bolts and extra nuts leads to increased angular momentum

Cheers
Chris

[ChrisGreaves]

They serve the function once served by lock washers. Some of us nuts got tired of trying to keep a supply of all sizes of lock washers.

Ah yes! Lock-washers.
Thanks Bob; what an old-memory guy you have turned out to be.
I have lock washers. In fact, I am rapidly accumulating comfortable numbers of every sort of fastener as I perform remedial work on whatever I find in the back of David's pickup truck as he sets off to the tip.

Knowing my luck, once I apply lock-washers AND lock-nuts, the wind will drop and we will have the calmest summer on record.
Cheers
Chris

[ChrisGreaves]

And there was me thinking that the blue colour indicated that Chris had been presented with USB 3 nuts!

Truth be told, that was my first thought, what with the internet of everything nowadays!
John, I don't know whether i should be happy that you and I are on the same wavelength, or sad.
Cheers
Chris

[ChrisGreaves]

Eileen's Lounge is home to many full-time nuts. I'm not sure it's the best place to ask about one-time nuts...

Ah Hans! When it comes to turbines, you are this nut's biggest fan!
Cheers
Chris

[StuartR]

I do recall from a brief stint working for an aircraft mechanic, or on a farm, bolts with threads that went in the opposite(?) direction of the shaft rotation so that the nuts couldn't work their way loose/off

You still get those on bike pedals, as well as many other places

[ChrisGreaves]

... bolts with threads that went in the opposite(?) direction of the shaft rotation so that the nuts couldn't work their way loose/off

You still get those on bike pedals, as well as many other places[/quote]
That was it, Stuart. Bike pedals.
Cheers
chris

[jstevens]

Hmmm...a bike, pedals, no wind and a turbine. Connect the bike to the turbine and pedal faster.

[ChrisGreaves]

Hmmm...a bike, pedals, no wind and a turbine. Connect the bike to the turbine and pedal faster.

28
Cheers
Chris

[ChrisGreaves]

... the blue insert is nylon which creates high friction as you have to cut a thread into it, and this prevents the nut from becoming loose. ...

More thoughts:
It seems to me that the nut can be re-used with success providing I squeeze a dab of Painter's Caulk, 100% Silicone Sealer or, at a pinch, LePage Multi-purpose White Glue (wood, paper, leather, crafts, etc etc).
I would expect any of these adhesives to provide enough friction to prevent loosening due to vibration, but to remain susceptible to my strong arm at the other end of a 14"-handle crescent wrench.
Cheers
Chris

[DaveA]

They just may stay on, the the designers used these for a good reason.
Being a retired from a aircraft company, we used these type for many reasons.
But the one time used nuts were designed to be used once.
Most of them do not cost much more than a standard nut.
Also they are used where one should NOT need to remove them, unless there was a lot of damage done.

[ChrisGreaves]

They just may stay on, the the designers used these for a good reason.

Hi Dave; "a good reason" I do not doubt, however I suspect that nowadays lawyers get involved and in some case stipulate conditions "just in case" of legal reasons. As well I am cynical enough to think that some manufacturers think of making their pocket-money from selling "only genuine parts".

Being a retired from a aircraft company, we used these type for many reasons.

This reasoning is closer to home; i am after all is said and done, dealing with a propeller with its huge angular momentum. I can visualize a blade spinning off in a high wind and then, being a form of airfoil, ending up in Elliston or Catalina.

Most of them do not cost much more than a standard nut.

This too is true, especially if you live in a city or perhaps a major town, but out here on the tip of the Bonavista Peninsula, anything out of the ordinary has to be ordered from e.g. Wisconsin, with attendant shipping delays, customs duties etc etc, so to me the cost is not just a couple of dollars, but a four-week delay.
I will ask my motor-mechanic neighbour next weekend if he knows of a supplier in St John's.

Also they are used where one should NOT need to remove them, unless there was a lot of damage done.

Or, as in my case, a desire to experiment with location. I figure that when I move the turbine from a ground-based station to the house roof, and then to the shed roof, I'd very much like to lower the 3-blade hub very carefully before tackling to 20Kg turbine-plus-tower-base.

To pre-empt the next question: multiple locations because as far as I can tell, this will be the first such turbine in Bonavista, and I would like to obtain data for power generation at different sites around my yard. People are quick to tell me "It HAS to be mounted on a roof" without giving any justification. I think that they mean "You get best results when mounted on a roof". Obtaining numeric data is a first step for measuring any improvement.
Cheers
And thanks for all your thoughts
Chris

[John Gray]

The closer to the ground, the more friction the wind experiences, and thus the slower it travels.
Do you have a jet-stream over Newfoundland? If you could put your turbine into this, you should get a lot of power.
Stay-wires might be a bit of a problem, but, hey, you're a resourceful chap!