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MG Midget and Sprite Technical - Split washers

Split washers, or whatever you want to call them, I might have forgotten but I can't remember ever seeing any written evidence that they actually perform any greater holding ability than a plain washer (which I know spreads the load and fills the gap between thread hole and nut).

Can anyone put up such information? (again?)
Nigel Atkins

https://engineerdog.com/2015/01/11/10-tricks-engineers-need-to-know-about-fasteners/
anamnesis

I acknowledge there are certainly references that say helical spring lockwasher is worthless. There are also references that provide a different picture.
A more complete quote from 4th ed of same book: "An introduction to the design and behavior of bolted joints" By John H. Bickford is listed below:
Quote (Bickford):
FIGURE 14.20 A helical spring lock washer would appear to be a fairly inefficient way to resist selfloosening;
but recent research—described in the text—shows that this washer twists and rolls when it's
fully loaded. Since that requires a clamping force that can equal 65% of the proof load of the bolt, this
washer can, indeed, provide significant resistance to self-loosening.

14.6.7.3 Helical Spring Washer
At first glance the helical spring washer shown in Figure 14.20 would appear to be of as little
value as the wave washer; unless the cut ends manage to bite into joint and nut and resist
relative motion the way the toothed washer does. Research at the Lawrence Technological
University in Southfield,Michigan, however, suggests that this device is more effective than it
appears to be [22]. Dr. Clarence Chambers has shown that, while this washer is flattened by
bolt tension equal to only 5% of its proof load, increasing bolt preload to 70% of proof will
cause the trapezoidal cross section of the washer to roll and twist down on the outside
diameter, which also grows. This complex action results in a washer spring rate which can
approach 65% of the spring rate of the fastener. That spring rate will dominate the behavior
of the fastener under load, and will reduce the amount of preload lost under a given applied
load. Retaining preload, of course, is an effective way to resist self-loosening.
anamnesis

Thank you stranger, and they don't come much stranger. :)

So I remembered but not fully correctly.

I'm not sure all modern made spring washers are made well enough to be as effective as previously perhaps.

So as with a lot of other things on the old cars, you can pick a belief that suits and you and stick with it.
Nigel Atkins

Ah Nigel I was wondering about that, thought maybe it may be a late model they went metric in 1971 didn't they. Anyway scrub the split washers, I have some UNC/F, depending on size.
L Langley

No stranger Nigel, he's been here before ,isn't that right, Peter---
William Revit

Willy,
note the " ... and they don't come much stranger". ;)

As usual from the poster lots of useful information, and perspectives from from both sides of the subject.
Nigel Atkins

Did I inspire you this question Nigel ? :D

I am really pessimist now when I read any review/study on internet... 99% of the time, every "classic" solution is in-appropriate, and only one solution is working amazingly great ! And you can purchase it at great price using the link below the article....

If you check the videos posted in the "comment" area of this article, you will find similar "scientific studies" telling the same as the article, and others telling the exact opposite. Which doesn't light our lantern, I know...

Just saying that for me, even being a "logical" person, I trust only what I see and what people with experience tell me, rather than Internet studies...

(so the answer is Nyloc, and preventive maintenance ;P)
CH Hamon

Get me thinking.... What are your opinion about threadlocker ? :)
CH Hamon

I like thread lock and stud lock and nylocs (if they're not poorly made) and not being an engineer I only use a nyloc once where possible. I also like half-nuts (locking nuts).

I use split washers in places but still not sure they do much good.
Nigel Atkins

I have had to have many bolts machined out after they have been put in with threadlocker.
L Langley

Yes you do need to be selective with the threadlock strength and where it's used but I've never had any trouble getting the fixings apart. Studlock can present more effort and hassle but again the few times I've had to remove a stud with it on they come out when intended rather than the stud coming out when not intended without the studlock.
Nigel Atkins

Personally I'm not a fan of threadlock. It shouldn't be necessary if everything is as it should be. You cant beat castellated nuts and split pins or wire for critical areas although I admit nyloc can be more convenient.

Trev
T Mason

It shouldn't be necessary to have to do, and redo, lots of things on our cars but with the quality of today's fixtures, fitting and parts unfortunately it often is.

I only have very limited experience but what little I have has taught me that there's a lot of poor quality parts and fittings around.
Nigel Atkins

Spring washers are everywhere on classic Japanese bikes. Used where vibration is an issue and thus where there is a risk of the nuts working loose. I have never seen a nut come loose where a spring washer is fitted. On British bikes they are almost completely absent. The only nod to anti-vibration control being the occasional split pin and castellated nut, yet even then on such key items as the rear wheel spindle nut, they can be alarmingly absent.
Oggers

Willy

I think you're getting your strangers mixed up.

There's a clue in "14.6.7.3 Helical Spring Washer" above ;o)
Dave O'Neill 2

Oh, it's Clarence then ?
GuyW

Dr Clarence, to you.
Dave O'Neill 2

LL maybe the wrong sort of threadlocker has been used?"There are many brands of threadlocker, in multiple grades using a standardized color-coding system. The most common are: Purple (light duty), Blue (medium strength), Red (high strength), and Green (penetrating low-high strength)."
David Smith

Interesting David I didn't know that, I will put that in my data file. I have suffered from it but have only used it quite recently, can't remember what for.
L Langley

Lawrence, you've probably taken factory/manufacturer items apart for investigation or repair and noticed blue on the threads of the screws, that's the stuff (well I guess it is).

If applying the threads need to be clean, for best results, and the "blue" (always check the label for actual strength and use) has always seemed to work for me the few times I've used it and it has been barely noticeable when undoing the fixing.

The 'red' 'stud lock' stuff may require heat to help it release the fixing.

Obviously with the poor quality of some modern fixings you need to take into account if the fixing will be weaker than the adhesive you're using.

I managed to extract a couple of stud-locked studs my mate couldn't but I did, by being impatient, brake one of the two studs, luckily I still had enough left to use a 'Super Wrench', remember them?
Nigel Atkins

No - just looked them up they look a bit more vicious than mole grips.
L Langley

Vibration from rallying on rough gravel stages kept on causing the fastenings in the door latch and window mechs on my pull handle B to work loose regardless of care in assembly. Until I got really crabby about it and applied thread locker everywhere. Problem solved.
Paul Walbran

I guess that after 23 messages one rather runs out of new things to say about a split washer.
GuyW

This thread was discussed between 30/08/2020 and 05/09/2020

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