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Lock Washer Failures

04/10/2019 2:13 AM

I just bought a trailer tongue jack for a trailer I built. (Modified for my use)

The hardware included mounting plates, mounting bolts, nuts, flats and lock washers.

Where would you put the flat washer and the lock washer?

I know what I did.

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#1

Re: Lock Washer Failures

04/10/2019 2:52 AM

Here is a vote for:

  1. [depending on strength of materials] flat washer onto bolt.
  2. bolt through the parts to be secured together.
  3. Flat washer onto bolt to spread the load of the lock washer.
  4. lock washer onto bolt.
  5. nut onto bolt and tighten-up.
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#2
In reply to #1

Re: Lock Washer Failures

04/10/2019 3:40 AM

Yes. Either that or 4, 3, 2, 1, 5.

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#3
In reply to #2

Re: Lock Washer Failures

04/10/2019 6:52 AM

I agree with PW, the lock washer is always adjacent to the nut. (Washer at tother end)

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#5
In reply to #1

Re: Lock Washer Failures

04/10/2019 9:29 AM

I agree if going with the written description.

The written descriptions states flats (plural) but, the image only shows 1. If going with the image, I would vote 1-2-4-5.

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#4

Re: Lock Washer Failures

04/10/2019 8:21 AM

Yes, I agree. Lock washer in contact with the nut and also in contact with the part being bolted. Flat washer at the bolt head. The lock washer won't work if either of the 2 surfaces against it will rotate.

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#6

Re: Lock Washer Failures

04/10/2019 10:03 AM

I think I would go another direction...

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#15
In reply to #6

Re: Lock Washer Failures

04/11/2019 10:41 AM

I like this answer. A lock washer requires constant tension in the bolt. Great for a static structural connection. But for a dynamic connection that is going to experience constant movement, I see the lock washer eventually loosening.

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#7

Re: Lock Washer Failures

04/10/2019 12:18 PM

Thanks to you all.

That's the way I assembled it.

Bolt, flat, plate, tongue, plate, lock, nut.

SE, the tare weight of the trailer is only 300# and over 50# of that is the 4'x 8' x 3/4" plywood floor to be replace by aluminum decking when I get time. I use it only to haul bicycles, so I want to keep it light. The castellated nuts would certainly do the job, but I only use it when picking up or delivering more than two bikes at a time, so the factory hardware is fine.

After I optimize the location finally, I'll cut the bolts to length and reassemble the unit. Since it will be permanent, I'll probably use thread locker too.

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#9
In reply to #7

Re: Lock Washer Failures

04/10/2019 12:50 PM

10-4...in that case I would go with standard nylon insert lock nut....

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#13
In reply to #9

Re: Lock Washer Failures

04/11/2019 7:12 AM

Nylok nuts are hard to beat.They will hold position even if not tightened down against anything.I have seen them hold for years under extreme vibration even when left as a gap setting. (Obviously,there are temperature limits.)

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#16
In reply to #7

Re: Lock Washer Failures

04/11/2019 10:54 AM

Your post was entitled Lock Washer Failures. Is there an actual failure, or just a potential one?

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#8

Re: Lock Washer Failures

04/10/2019 12:20 PM

Then, of course, there is the Nord-lock (usual disclaimer) system:

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#10

Re: Lock Washer Failures

04/10/2019 2:05 PM

MIG

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#11
In reply to #10

Re: Lock Washer Failures

04/10/2019 4:12 PM

Too late. I've already cut the bolts to length and finalized the install. I should have done it when I first bought the trailer. It would have saved wear and tear on my old back!

Besides, I save the MIG for the big jobs.

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#22
In reply to #10

Re: Lock Washer Failures

04/11/2019 10:30 PM

TIG.

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#12

Re: Lock Washer Failures

04/11/2019 7:09 AM

If you are really serious about locking the nut,NASA says that spring-type lock washers are useless in critical applications. My recommendation would be to use Red Loktite to get a secure connection. If you are really serious about fasteners,read this link: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900009424.pdf

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#14

Re: Lock Washer Failures

04/11/2019 10:02 AM

You can also stake the nut to the bolt with a center punch or chisel to deform the joint where the two fasteners come together. The amount of hold is proportional to the amount of deformation.

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#17

Re: Lock Washer Failures

04/11/2019 11:13 AM

Some random responses.

The question was "Where would you put the flat washer and the lock washer?"

I suppose to prevent potential failures.

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#18
In reply to #17

Re: Lock Washer Failures

04/11/2019 11:33 AM

I thought we had 30 minutes to edit????

Some random responses.

The question was "Where would you put the flat washer and the lock washer?"

I suppose to prevent potential failures, knowing that I wold use the supplied hardware.

I have seen lock washers over flats in many instances and I always though that was incorrect.

Yes, I've read the NASA piece. (Worked in aerospace for 25 years) and also assembled truck mounted cherry pickers and man lifts prior to that.

Red Loctite® is over kill for this application, and difficult to disassemble without a torch. I do have it though.

This trailer will sit, stationary, for 99.5% of its life, so the supplied hardware is more than adequate.

Thanks for all the great responses.

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#19
In reply to #18

Re: Lock Washer Failures

04/11/2019 11:50 AM

Red Loctite®, phooey. If you're going into overkill mode, make sure it really is dead. MIG weld the blighter.

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#20
In reply to #19

Re: Lock Washer Failures

04/11/2019 1:10 PM

I used lots of blue and red Loctite when I rode motorcycles in the desert in 1979 and later.

No, it's done and I've moved on.

.....................I was cutting wheel chocks for my trailer and another trailer, from a 3 1/2 x 5 1/2 (formerly 4 x 6) and the kerf closed up and locked the blade firmly half way into the wood. I had to remove the blade from the saw and remove the wood from around the blade. I only have 3 pretty wheel chocks now.

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#27
In reply to #20

Re: Lock Washer Failures

04/13/2019 7:33 AM

My son rode competitive Motocross for years.The best we found for the purpose was Red Locktite.Easy to remove with impact tool,or a gentle tap on the wrench with a hammer. Just never disassemble when engine is hot when using RL,it will sometimes take out the threads with it.However,when this happened,an insert provided an even better solution than the factory threads. Never use a split washer on aluminum,it will damage the surface. When a split washer is fully compressed,it has no tension.It only works if the nut has begun to loosen. It is no better than a flat washer when fully compressed. The fault here is that the locking action only occurs too late,after the original torque has been reduced. In a non-critical application, split lock washers are just fine.

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#29
In reply to #27

Re: Lock Washer Failures

04/13/2019 11:06 AM

" It is no better than a flat washer when fully compressed."

Probably true, but it still might (probably) keep the threads engaged so that the nut/ bolt stays in place.

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#21

Re: Lock Washer Failures

04/11/2019 2:13 PM

Nut screws washer and bolts. The nut get the spring washer and the bolt head the flat washer. But if you are smart, you add a flat washer after the spring washer to save damaging the substrait surface, i.e. galvanise, epoxy paint.

Nut, spring washer, flat, flat, bolt head. And a touch of locktite on the threads. Torque. Job done, no charge, no comebacks. Hunky Dory.

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#23

Re: Lock Washer Failures

04/12/2019 9:00 AM

In structural steel, I was told the washer always goes on the side that is going to be turned to tighten the connection.

As for this application, I would have to agree with some other posters that any type of locknut would be better than the lock washer (for these to function as intended you have to apply the correct torque to the assembly). There are Nyloks (ESNA) nuts, pervailing torque nuts - aka - stover nuts and bi-way locknuts (center lock). Any of these are preferred, at least to me.

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#24

Re: Lock Washer Failures

04/12/2019 1:52 PM

This has been interesting. Again, opinions are all over the map.

One side says split washers "dig in" to the parent material. I can buy into this as I have experienced it myself. Other side says split washers put the threaded fastener in tension. I say BS to that because a fastener will be in tension, washer or not, if torqued properly.

I thought this was a good source:

10 Tricks Engineers Need to Know About Fasteners – EngineerDog

Bolt Sizing Calculator (EXCEL)

I just checked the jack and all the nuts are still tight.

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#25
In reply to #24

Re: Lock Washer Failures

04/12/2019 2:30 PM

Interesting, thanks for the link.

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#26
In reply to #24

Re: Lock Washer Failures

04/13/2019 4:15 AM

"... One side says split washers "dig in" to the parent material. I can buy into this as I have experienced it myself. ...."

.

How did you 'experience it' yourself? Did you see the surface gouged after disassembly and infer the 'digging in' kept it from loosening?

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#28
In reply to #26

Re: Lock Washer Failures

04/13/2019 10:53 AM

No. It wasn't an inference, it was experienced.

Having to use two wrenches to loosen the nut until it was totally disengaged from the washer gave a good indication.

Yes, there was evidence of metal removal also.

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#30
In reply to #28

Re: Lock Washer Failures

04/13/2019 12:21 PM

I understand you may not realize you are inferring.

Typical torque (either specified or reasonable) on most nuts will be far more than is required to flatten the typical split spring washer.

The indention and gouging occurs prior to flattening, as when it is flat....it is flat, there is no protrusion below the rest of the surface to cause any digging in.

Moreover, the amount of loosening required before a split spring washer begins to become helical again means the game is over before any 'digging in' could help.

At best a split spring washer provides some limited tension in an already loosened nut/bolt assembly potentially keeping the loosened nut from completely disengaging quite so rapidly.

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#31
In reply to #30

Re: Lock Washer Failures

04/13/2019 12:33 PM

Don't play your arrogant word games with me! Don't tell me that I may not realize something.

I knew as soon as I responded that you were going to come back and insult me, just by the way you worded your question.

You are free to think anything you like, but do NOT think you can tell me what to believe!

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#32
In reply to #31

Re: Lock Washer Failures

04/13/2019 1:55 PM

Screw this, this thread is stripped, its nuts. I'm bolting.

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#33
In reply to #31

Re: Lock Washer Failures

04/13/2019 3:23 PM

The split lock washer will dig in if it is harder than the base mateial.It is especially damaging on aluminum,but you know that I m sure.You are a very intelligent and informed guy. This is perfectly fine for most applications,but not if it is a life-or-death situation. That is why NASA will not use split lock washers,and considers them(for their purposes,to be useless.)For trailer balls,etc,I personally prefer inside+outside star washer,also called shake proof washers,in 304 Stainless. I do not think anyone was trying to impune your knowledge or experience,or opinion.No one can insult me unless I let them.I refuse to let anyone control my adrenal gland. Take the high road of a superior human being,not the ordinary.

This posting is not intended to insult,belittle,impune,harass or offend anyone.Please take it as such,and don't take it personally.

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#35
In reply to #33

Re: Lock Washer Failures

04/13/2019 5:34 PM

Thanks.

The point of the original post, where does the lock washer go in the stack up, was lost soon after I posted.

I do appreciate all the responses, but it's only a small trailer, and I had no intention of going to the hardware store to buy 4 nyloc nuts, which I would have used if needed.

The trailer is used to pick up and deliver BMX bikes that I refurbish for kids. 15 miles is a long trip.

I DID use red thread locker on some smaller hardware that I added to the trailer today.

My nut/bolt/washer supply does not include split washers.

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#34
In reply to #31

Re: Lock Washer Failures

04/13/2019 5:10 PM

There arw lots of things I don't realize. There may he some you don't realize as well.

If you were to come to the realization that we all havr things we may not realize, when someone suggests such a thing, you might also realize how silly it is to take offense at such a tautology.

....unless of course you believe you have realized everything there is to possibly be realized.

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#36

Re: Lock Washer Failures

04/15/2019 4:41 AM

Radio: "Reports are coming in of a serious sexual assault that took place in a launderette last night. The assailant, who is described as a madman, reportedly escaped and is till at large."

The newspaper headline read: "Nut screws washers and bolts."

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#37
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Re: Lock Washer Failures

04/15/2019 2:47 PM

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#38

Re: Lock Washer Failures

04/16/2019 3:43 AM

The other way around than whats shown.

Lock washer next to nut, washer towards the screw head.

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#39
In reply to #38

Re: Lock Washer Failures

04/16/2019 11:06 AM

Agreed. That was a stock picture I lifted off the net.

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