How is making the system weaker logical when using the nuts the correct way around is easy?
In this case, secondary school, obviously a better place than where you didn't learn.
8<
What's ambiguous about it?
Its the wrong way of doing it! It is dangerous as it is using the weak component where it should be using the strong component. You should rethink your engineering education as it has failed.
You are more stupid than I thought, now you are imagining I said things. I have never mentioned or commented on other forms of nut locking. Is this just another of your attempts to claim I said something wrong by making it up?
Yes that is what it does when its under the main nut and exactly what it doesn't do when its on top.
More ambiguity, if not downright nonsense if linked with your previous statements. The purpose of the main nut is to clamp. The locknut on top doesn't reduce that ability one iota.
You went to a Technical School? I would have thought they were abolished before you were out of nappies.
You obviously expect our readers to take the rubbish you generally write on trust.
Lock nuts were designed thin to use on top as they didn't need to to be stressed as greatly as full thickness nuts. It is counter intuitive to use them below the clamping nut even if it turns out that way is more effective.
You are not competent to make that judgement.
No, just me faithfully reporting what has gone before but you couldn't resist the blatant lie:
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You are wrong here too so go away and find something you understand.
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Can't you even make your mind up as to which fiction you want to endorse. Locknuts on top do work. Whether they work as well as locknuts underneath is the issue.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "dennis@home" saying something like:
How can it possibly do that? If the thin nut is on top and is only being tightened against the lower nut, it cannot slacken the lower nut.
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bit, "The inner nut is then slackened back and tightened against the outer nut." is wrong in most cases. If that's what you're referring to, it only applies to a bolted assembly which isn't tightly clamped. The vast vast majority of locknuts I've seen and used are where the main nut is torqued down and then held securely while the locknut is tightened down onto that.
The lock nut can only lock the other nut if they oppose each other on the threads. Just tightening another nut down on top does not lock it any more than tightening it down on the job. If it is locked then both nuts are forced against the threads in opposite directions. This means the bottom nut is not taking any load as its against the wrong slope of the thread to be taking load and thus all the load is against the top nut.
Basically any fixing where it has the thin nut on top is wrong, if you see one and its unsafe if it fails then you need to get it fixed.
Anyway I have decided this has gone on long enough..
Lets take some simple cases to show why its wrong to put the thin nut on top.
Lets call the first nut A and the second B.
1:
You torque A down to say 10ftp. Then you torque B down to say 5ftp. This is just like having nut B straight onto the job and nothing will stop it loosening. Hence no nut is locked.
2:
You torque A down to 10 ftp. You Torque B down to ~10.1 ftp. Now A is just a washer, it applies no force of its own. No nut is locked.
3:
You torque A down to 10 ftp You torque B down to > A. Now A is acting against B. The threads on A are pushing against B not the job, on the opposite face of the thread. Now the nuts are locked together on the bolt by opposing forces.
The forces from B are transmitted through the body of the nut A to the job. Nut A does not have any loading on the thread from the job as it is forced against the wrong face of the thread.
Now from the three cases you can see only case 3 locks the nuts, in the other cases they will just get looser and fall off. Now you can also see that there is no force towards the job on nut A when it is locked. All the load is on nut B. This is the thin nut in your case and it is not designed to take the same load as the thick nut. In effect you are putting the locking forces on to the thick nut and the load forces onto the thin nut. I just hope there is enough over engineering built in to take the 50% less load bearing capacity of using the lock nut to support the load.
Far too much, most of which is irrelevenat or destroys your argument about the position of the thin nut. It's classic Dennis, deliberately choosing to miss the point and start referring to the "lock nut" and conveniently ignoring yoour previous vociferous argument about where the thin nut goes.
I'm beginning to think you and Dennis are just one.
Well of course lock nuts go on top, everybody knows that. You've conveniently forgotten that the crux of the ergument was which should be the thinner nut.
Or they were using two nuts of the same thickness so it was a moot point.
Of course you are not alone. Stop trying to twist the argument.
Now the intersting bits of what you posted:
Read it again. An erroneous illustration has "caused many engineers to put the jam nut on top" IN ERROR.
More to the point, it says put the THIN one on the bottom.
So, again, the THINNER nut should be on the bottom.
And again, the lower one is thee thinner one.
So you could play like Dennis and try to throw something else in to divert the argument from the fact that you were WRONG about the thin nut going on top.
Just be gracious and admit that you were 100% wrong in your argument that the thin nut should go on top.
No, I meant what I said. That a small part of what he said is now accepted as fact in some quarters, particularly on the other side of the pond.
A locknut of the old fashioned sort is a thin nut manufactured to a set standard. Despite Dennis' protestations and now yours it is not cut and dried where the lock nut goes. Both methods have advantages.
Have you ever known Dennis to admit to being wrong or to tell the truth when a casual lie serves his argument better?
Don't confuse yourself with logical absurdities. A specialist locknut of the sort under discussion is a thin nut when compared to a standard nut.
If you read what you cited you should have noticed that one site suggested the use of 2 standard nuts when clamping force was required immediately. If you look immediately above I actually referred to "dimensions for locknuts". What more information do you need before you understand what a locknut is? What it is and how it is used are two separate matters.
What am I twisting. Nobody as yet has tried to refute what I said about usage in the past. Even Dennis just says it was wrong.
I comprehended it perfectly the first time around. A text that the commentator admits was the best around had an error in the opinion of the commentator.
Where else would you put the locknut if not on the top?
In his opinion, he is after all being consistent.
In his opinion, he is after all being consistent.
I included it because I was curious about the alleged use of first angle projection.
I can't because I wasn't. There are arguments in favour of both schools of thought and shortcomings with both methods as well.
The only advantage in putting the thin one on top is that you can use a thicker spanner.
I never lie, unlike you. You even lie in the statement above. There are plenty of times I have admitted I was wrong in this group. The fact that I haven't to you is because you are wrong, in every case so far!
That's because the thicker nut should provide the clamping force and it can't when its on the bottom as its the top one that provides the clamping force. So they tell you to use two thick nuts to avoid overloading the thin one prior to the thick one being fitted.
Note they do not tell you to use a thin one on top even though putting the thick one on first would provide clamping force. This is because they know that after the second one is fitted it is the second one and only the second one that provides the clamping force. Are you really too thick to understand something so simple or do you think you are gaining something from arguing a wrong point?
I have told you why, you are just to stupid to listen.
Can't you even remember what the argument is now?
There are no real arguments supporting weakening the fixing just to put the thin nut on top.
So what do you think is the ideal thickness for a spanner if money is no object?
Yet another lie.
You lied in the apology thread when you said -4.5 had not yet appeared in the data thread.
You lied in this very thread as I have already highlighted above and which is repeated below yet again as a reminder of your dishonesty.
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No, just me faithfully reporting what has gone before but you couldn't resist the blatant lie:
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You are wrong here too so go away and find something you understand.
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Yet another lie.
Maybe you have, maybe you haven't, but I have yet to see even one instance, but as I don't read all the threads these days the possibility exists that you have admitted you were wrong in a thread I haven't read. But really you are displaying your usual abysmal lack of comprehension. I posed a question. I did not make a statement of fact.
What a load of garbled nonsense.
By continuing with such absurd rubbish all you are doing is displaying to everyone that your thought processes are completely addled.
Me stupid? You are the one who has gone to great lengths to demonstrate that you don't know how either locknuts (the ones on top) or jam nuts (the ones underneath) actually work.
It is often said irony is wasted on Usenet. There is after all only two positions for the locknut - either above or below the main nut.
There you go again with another preposterous statement. Putting the locknut on top doesn't weaken the fixing.
Grimly seems busy atm so I thought I would reply just to keep the argument going.
You wish. Long enough to show you up as a complete ignoramus but not long enough to define all that is wrong with your rambling rantings.
Doesn't matter how simple you try and make it you just make it complicated, verging on incomprehensible and wrong.
Why not stick with locknut and main nut?
The essence of a locknut is that you lock it against the main nut. While your silly example will provide some locking despite what you say it will probably not be as much as would be generated had the lower nut been restrained as B is tightened. I say probably as it is by no means certain that A would actually move in this scenario.
Oh dear Dennis is retiring hurt from yet another thread with his customary show of childish petulance.
You wish.
With an acknowledgement to Blue Peter (a program I never actually watched as it wasn't around when I was a child and in any case we didn't have a television) here is a little something I prepared earlier. I leave it to our readers to decide who it is who has provided the more sensible answers:
Locknuts
To start at the beginning , the very beginning (mainly for the benefit of Dennis) it is necessary to consider the typical usage. A locknut would be used where nut and bolt is likely to be subject to vibration in service and the usage is not sufficiently critical to warrant a positive locking method, ie one where only component failure would lead to the fastening coming undone.
Locknuts of the sort in question are thin compared to the depth of the main nut and it is the main nut that provides the clamping force regardless of whether the locknut is positioned outside the main nut or under it. Dennis maintains that putting the locknut on the outside means that the locknut has the clamping role which the main nut has lost by virtue of the change in location. Of all the many stupid things Dennis has said this probably takes the biscuit as the most monumentally stupid to date but I could be wrong about that, being spoilt for choice.
For a locknut to work it has to be tightened up against another nut. The tension this exerts on the part of the bolt between the two provides both for friction and/or distortion in the threads and pressure between the two mating surfaces. The first acts to prevent the combined nuts becoming undone and the second acts to prevent the two nuts going their separate ways. From what Dennis has said he seems to understand this at least in part when applied to the locknut under the main nut but as he discounts it entirely for the locknut outside the main nut any understanding must be of a very superficial nature.
Consider two standard nuts locked together on a thread. Tighten such an assembly up really hard and permanent damage will result to the threads in either nut or the thread on the bolt or, quite possibly all three. Do the same with a locknut tightened against a full depth nut and the result will be a stripped thread in the locknut with only a minor chance of damage to the bolt.
Where the locknut is used outside the main nut the main nut is tightened up at the required torque and the locknut is then tightened up to a lesser torque commensurate with its thinner section while the main nut is prevented from turning. The section of bolt between the locknut and main nut is tensioned and some degree of locking is introduced. If the locknut is accidentally tightened to the point of failure that should be noticed on assembly due to the sudden extra give which is a safety feature.
When the locknut is placed under the main nut the situation is considerably more complex. One of the sites cited earlier in the thread helpfully sets out the recommended procedure with the locknut being done up lightly before being held stationary while the main nut is tightened down on top of it. That gets over the first hurdle I thought of - how do you torque up an assembly to the desired setting when the initial clamping device can only take a strictly limited torque.
As the main nut is tightened the locknut is relieved of its duty as a light clamp and floats freely on the thread until the clearance in the thread is taken up after which the locking action starts to build but that is where the certainty ends. In order to get the most advantageous locking the same considerations apply as when the locknut is on the outside - that the tension in the bolt between the two nuts should be as high as possible consistent with the locknut not stripping its thread. The problem then becomes how to achieve this objective and at the same time tighten up the main nut to the correct torque. If there is not enough slack in the assembly that point will never be reached. Too much slack and the locknut thread is stripped without anyone being the wiser.
When first presented with the idea of the locknut being under the main nut I thought I could see some advantages in that method. I am sorry but I was wrong. All the supposed advantages have disappeared in the wash.
Metal is elastic. Put the thick nut on first and torque up and it takes all the tension in the bolted joint, because it is using the upper sides of it's own threads against the upper sides of the bolt, stud threads. Put a thin nut on the top and that will transfer the tension by compressing the main nut down the threads of the bolt by stretching the stud or bolt and remember the thread tollerances here. This will take away the thread contact of the main nut to bolt contact. The main nut will not be contributing to the tension stress strength of the the bolted joint. The full nut will result in a weak bolted joint, if it is used this way in tension.
I hope this is clear, as I have done a lot of driving over the last 2 days.
Mention was made earlier about locking tabs and Nylock nuts. Just to clarify, there are three ways of locking a nut.
Plain nut and bolt, no locking. Rarely used outside of anything critical. Not sure what class they were.
Lock nuts that may be Nylock or crimped nut metal to prevent vibration unscrewing them. Class 2 locking.
Locking tabs, split pins and wire locking to provide a visual check that it had not been undone in use. And there is another way of using a plain nut on a bolt and peening the bolt so the nut cannot be removed.
I don't agree with his conclusions but that is no reason to call him a liar. I set out my opinion at some length in the message timed at 19.55. If Dave wishes to continue arguing there I will be happy to accommodate him.
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