Split washer/spring washer... Useless or not?

The problem of fasteners coming loose may come down to the simple fact that they have not received the correct amount of torque. I once permanently solved the problem of ammunition feed jams in the 30mm Aden guns aboard the CAC Sabres after I discovered the the Unbrako screws holding the bottom plates in the feed mechanism had a specified torque which had never ever been applied, as the torque was not substantial enough to be able to use a normal Warren-Brown tension wrench. I made my own crude tension wrench and torqued all the screws up in the correct sequence to the book amount and the problem went away. For good measure, I also applied a centre punch to the rim of each of the Unbrako screws. :)
 
lowpugV2 said:
That's the equivalent of what I read. Question is, what does NASA use? Admittedly, if I see a NASA approved logo I generally buy. Great marketing campaign that moon landing.
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From the NASA publication "Requirements of Threaded Locking Systems in Spaceflight Hardware" 2018.

"Any bolt requiring preload to function or that is applied to a rotational joint must have a secondary mechanical locking system".

Safety wire, cotter pins and safety cables are given as examples.
 
Greenpeace said:
From the NASA publication "Requirements of Threaded Locking Systems in Spaceflight Hardware" 2018.

"Any bolt requiring preload to function or that is applied to a rotational joint must have a secondary mechanical locking system".

Safety wire, cotter pins and safety cables are given as examples.
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F**k NASA! What holds your car wheels on? Safety wires? Lock nuts? Tab washers? Big fat welds? No, I think it is torque. Usually applied by an apprentice with a nut runner and at 250% of the specified value.

Were I driving my vehicle in space there might be a reason to apply NASA's rules although I can't figure out why torque doesn't work in space. They do say no-one can hear you if you scream. Get real!
 
Kim Luck said:
F**k NASA! What holds your car wheels on? Safety wires? Lock nuts? Tab washers? Big fat welds? No, I think it is torque. Usually applied by an apprentice with a nut runner and at 250% of the specified value..
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No, but they're not held on with normal bolts and spring washers either.🤷‍♂️
SAE J2315 and J2316 cover the details of the engineering considerations involved in the simple task of keeping a wheel on. It's not just stand alone torque.
 
Greenpeace said:
No, but they're not held on with normal bolts and spring washers either.🤷‍♂️
SAE 2315 and 2316 cover the details of the engineering considerations involved in the simple task of keeping a wheel on. It's not just stand alone torque.
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What is the CE standard?
 
An engineer who trained as a fine mechanic a watchmakers collage in Austria (first year study subjects were identical to the watchmakers) told me that threads are cut in a way so they are self locking. He actually uses a drop of oil on the thread prior to putting a nut on and just using a flat washer. He claims that he has no problem with nuts becoming loose🤷‍♂️
The self locking is buggered once a thread is over torqued.
I still use various Loctite products (not on wheel nuts) until i understand what he is talking about.
 
Kim Luck said:
SAE is an American Imperial standard. What is the standard for the EU?
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Still not sure of the relevance of muddying the waters with different standards, I'm sure China have one too. The SAE is recognised as having a little bit of knowledge in the field.

Going back to wheel retention, all upper level motor sport regulates that some form of mechanical locking must be employed.
They musn't be confident in the "apprentice with a rattle gun is safe enough" theory.🤷‍♂️
 
I would suggest that the internal thread in the arm is worn/damaged. The standard thread is M8x1.25. Re-tap to M10x1.25 and your problems will disappear. Nothing will hold a bolt in the worn hole.
 
Greenpeace said:
Still not sure of the relevance of muddying the waters with different standards, I'm sure China have one too. The SAE is recognised as having a little bit of knowledge in the field.

Going back to wheel retention, all upper level motor sport regulates that some form of mechanical locking must be employed.
They musn't be confident in the "apprentice with a rattle gun is safe enough" theory.🤷‍♂️
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There are 20,100,000 road vehicles currently registered in Australia travelling more than 150,000,000 kilometres annually, the vast majority of which are not under any NASA or FIA requirements regarding keeping their wheels on. :cool:
 
Kim Luck said:
There are 20,100,000 road vehicles currently registered in Australia travelling more than 150,000,000 kilometres annually, the vast majority of which are not under any NASA or FIA requirements regarding keeping their wheels on. :cool:
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And 1000s of vehicles worldwide lose their wheels every year. Nordloc also market wheel nuts to address this concern.
Probably that apprentice with the rattle gun at work again.

There's a plethora of industries where they mandate telltale wheel nut tags on their work vehicle fleets
I don't think it's because they "look cool".
Ergon Energy recently put out a circular to their maintenance crews regarding a spate of wheels cracking and/or detaching on their heavy 4WD trucks.
 
PeterT said:
I would suggest that the internal thread in the arm is worn/damaged. The standard thread is M8x1.25. Re-tap to M10x1.25 and your problems will disappear. Nothing will hold a bolt in the worn hole.
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Good, simple, elegant logic.
 
Greenpeace said:
And 1000s of vehicles worldwide lose their wheels every year. Nordloc also market wheel nuts to address this concern.
Probably that apprentice with the rattle gun at work again.

There's a plethora of industries where they mandate telltale wheel nut tags on their work vehicle fleets
I don't think it's because they "look cool".
Ergon Energy recently put out a circular to their maintenance crews regarding a spate of wheels cracking and/or detaching on their heavy 4WD trucks.
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Regardless of your arguments the reality is that properly torqued wheel nuts on suitable wheel studs do the job and have done so for the past 100 years or so without the necessity for any additional retaining devices. Cracking wheels are a manufacturing problem, not a wheelnut problem and wheel nut tags simply look cool but still only indicate that a wheelnut has not been tightened to it's correct torque, from which it will not undo on it's own. Those not old enough to remember using "knock-on" central wheel nuts may well be amazed that "torquing" the knock-on nut with a hammer would prove sufficient to keep it on a vehicle for the duration of a Le Mans 24 hour race but them's the facts!
 
Kim Luck said:
Those not old enough to remember using "knock-on" central wheel nuts may well be amazed that "torquing" the knock-on nut with a hammer would prove sufficient to keep it on a vehicle for the duration of a Le Mans 24 hour race but them's the facts!
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How many of those Le Mans knock-ons use RH threads on the LH side of the car? The LH/LH, RH/RH side method of attachment was self tightening by design.
Not really relevant.

Generally when wheels come loose it's on the LH side with the now "normal RH attachments". But of course in days of old many manufacturers knew this and provided LH studs on the LH side to mitigate the problem.
Gosh even my old Ford truck has LH threads on the passenger side.
 
PeterT said:
It’s a common problem on 205 and 306 arms.
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As simple as re-tapping sounds, I'm not sure I can tackle without buying tools and then messing it up! Do I need to do anything to the aperture on the end plate?
 
Greenpeace said:
How many of those Le Mans knock-ons use RH threads on the LH side of the car? The LH/LH, RH/RH side method of attachment was self tightening by design.
Not really relevant.

Generally when wheels come loose it's on the LH side with the now "normal RH attachments". But of course in days of old many manufacturers knew this and provided LH studs on the LH side to mitigate the problem.
Gosh even my old Ford truck has LH threads on the passenger side.
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What you say may be correct, but in the ten or so Renaults plus other cars I have owned and some of which I have rallied I have never lost a wheel or broken a wheel stud in nearly a million kilometres and they have all been RH threads.

Here's a tap and drill chart that also has torque values in lbs/ft for those of us with older torque wrenches:

https://www.industrialmetalsupply.com/documents/Metric -Tap-and-Drill-Chart.pdf.pdf
 
lowpugV2 said:
As simple as re-tapping sounds, I'm not sure I can tackle without buying tools and then messing it up! Do I need to do anything to the aperture on the end plate?
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Would you like me to do it for you?
 
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