Does this bolt need a washer? Or is that built-in ?

[bubinga]

No lock washers. Split LWs are useless on metal to metal joints and extremely rare on vehicles today

Really?
They don't work?

 

[IdahoMan]

Question: Does a washer protect the surface of the material that the bolt is being used on.. For instance, if you have a painted surface and you are tightening the bolt against it wouldn't the underside of the bolt head be rubbing against the paint while it was turned? Would placing a washer between the surface and bolt cause the bolt to rub against the washer while the washer simply pressed against the surface, or would the washer start spinning too?

 

[bubinga]

The only lock washer that actually works is a very expensive and special one called Nord-Lock. It is not a split washer. Despite your view on NASA, etc, the test data does not lie.

what about Ny-lock, you don't like them either?

 

[American Locomotive]

what about Ny-lock, you don't like them either?

Nylock nuts are a prevailing-torque type fastener. Even if pre-load is lost, there is still a significant torque that must be applied to the nut for it to come off. Prevailing-torque type fasteners are a proven technology, but make assembly and disassembly more difficult.

Split-washers have been shown to be useless.

 

[bob15]

Problem with NyLok nuts is they cannot be used in high temp applications as the nylon will melt, making it just another regular nut on a bolt that can and will loosen up in time. If you want to use a locking nut in higher temp applications, you need to use a distorted thread type nut.

 

[seber]

Split-washers have been shown to be useless.

Split washers are still used in professional applications because they work. They do not prevent the fastener from loosening. They prevent it from coming off. Just as prevailing torque systems do. Look at what happens to the mating surfaces after you remove one. The ends of the washer dig into the surface of the part. The nut will start to loosen and then the washer ends dig in and prevent loss of connection. They are definitely not useless. It is just a matter of appropriate application.

 

[Sloper0204]

All this argument about lock washers, why not just run DTI's?

The engineers involved predicted exactly what happened. They were overruled by management.

Yes, because engineers are infallible.

I've seen engineers make just as many bad decisions as management has.

 

[tym]

The Nord lock is not commonly used because it a one time use thing that has to be precisely torqued. Whats common on a lot of German stuff is a curved serrated flat washer

For what it's worth, the Nord-Lock people say you can reuse the washers if they are not badly worn.

I used a few sets to hold on some alternator bolts on a Camaro that kept loosening on their own. They previously had split "lock" washers.

 

[bubinga]

Nylock nuts are a prevailing-torque type fastener. Even if pre-load is lost, there is still a significant torque that must be applied to the nut for it to come off. Prevailing-torque type fasteners are a proven technology, but make assembly and disassembly more difficult.

Split-washers have been shown to be useless.

Problem with NyLok nuts is they cannot be used in high temp applications as the nylon will melt, making it just another regular nut on a bolt that can and will loosen up in time. If you want to use a locking nut in higher temp applications, you need to use a distorted thread type nut.

Makes sense, thanks guys,

 

[bubinga]

Nylock nuts are a prevailing-torque type fastener. Even if pre-load is lost, there is still a significant torque that must be applied to the nut for it to come off. Prevailing-torque type fasteners are a proven technology, but make assembly and disassembly more difficult.

Split-washers have been shown to be useless.

That's crazy, all these years, we thought they were good.

 

[Bighead38]

The split washer has a very specific use. That is where the bolt or screw is too large to properly preload. The split washer then applies tension that the shank cannot. Trailer hitch balls are one example. Proper torque for a 3/4 hex nut on a trailer ball is on the order of 365 foot pounds. How many do you think are tightened to that spec? The same thing happens on farm equipment. Farmers do not carry a torque wrench around on the tractor.
As an aside, all the photos in this series have been screws not bolts. A bolt is not designed to be turned. That is the definition of a screw.

How do you feel about lag bolts? Jk.

I used stage 8 locking bolts for headers on my mustang. They worked great.

https://www.stage8.com/

 

[Steve_P]

That's crazy, all these years, we thought they were good.

Old habits die hard. Again, they were proven useless by test data in the 1960s but people still use them today. They were not on flywheel or connecting fasteners in the 1960s for some reason it's uncommon to see them on cars built today unless they're on a plastic part, above a flat washer. So some engineers did get the data. They have been replaced by flange nuts and bolts.

 

[American Locomotive]

Split washers are still used in professional applications because they work. They do not prevent the fastener from loosening. They prevent it from coming off. Just as prevailing torque systems do. Look at what happens to the mating surfaces after you remove one. The ends of the washer dig into the surface of the part. The nut will start to loosen and then the washer ends dig in and prevent loss of connection. They are definitely not useless. It is just a matter of appropriate application.

They are useless. Dozens have tests have shown that they don't "dig in" at all, and in high-vibration environments, nuts with split washers are actually MORE likely to spin off.

 

[Steve_P]

The engineers involved predicted exactly what happened. They were overruled by management.



Sent from my iPad using The Garage Journal mobile app

NPR interviewed that engineer decades later. It was really sad. He was in his 80s at the time of the interview. He blamed himself for the accident because he caved to management. Not that he could have stopped the launch, but he thought he gave in too easy. He lived with that for decades. After the interview, hundreds of listeners wrote letters to him and said it wasn't his fault, that he did all he could. He changed his mind and died shortly after. A happier man per his wife. Really sad story but a slightly better end for him

Edit:
https://www.npr.org/sections/thetwo...ster-challenger-engineer-still-blames-himself

 

[ChrisLS8]

Split washers are still used in professional applications because they work. They do not prevent the fastener from loosening. They prevent it from coming off. Just as prevailing torque systems do. Look at what happens to the mating surfaces after you remove one. The ends of the washer dig into the surface of the part. The nut will start to loosen and then the washer ends dig in and prevent loss of connection. They are definitely not useless. It is just a matter of appropriate application.

I've never once seen them DIG IN.

 

[Steve_P]

....The Nord lock is not commonly used because it a one time use thing that has to be precisely torqued. Whats common on a lot of German stuff is a curved serrated flat washer

Nord lock is not common because it's expensive. A half inch size Nord Lock washer costs about a dollar. That is a lot of $ for an auto manufacturer where every penny counts. And all critical fasteners are precisely torqued.

Split LWs are not used in critical applications. They're not on connecting rod fasteners, main bearing cap fasteners, flywheel fasteners, turbine blades......because they don't work. The test data proves it.

 

[Steve_P]

A true bolt can only be torqued by a nut. Think plow bolt or carriage bolt or other fastener that has no provision for a tool to turn it by the head. If you can torque the fastener by its head then it is a screw. Adding a nut to a screw does not change it into a bolt.

Now the above is changed by local opinion, culture, and industry. The above is what I follow.

lg
no neat sig line

This is the correct technical definition. What most call a "bolt" is a hex head cap screw. We all know what a socket head cap screw is. But if if has a hex head most call it a bolt. the only real bolts can't be turned; like a carriage bolt. But good luck asking for 3/8" screws at a fastener store.

 

[Steve_P]

I missed the memo... When was this discovery made?

1960s. Please read the thread from the start and the links to test data that proves it

 

[eyeball]

1960s. Please read the thread from the start and the links to test data that proves it

With this being settled science, it’s crazy that in this day and age of cost cutting and penny pinching manufacturing you still see them being used.

 

[American Locomotive]

With this being settled science, it’s crazy that in this day and age of cost cutting and penny pinching manufacturing you still see them being used.

From my experience in manufacturing, there are a lot of companies that have been doing the same thing forever, and continue to do so simply because that's the way they've always done it.

You'll see it a lot in industrial and agricultural equipment, where they tend to develop a product and then make it for 30 years without many changes.