Interesting info on lock washers

[bigb]

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https://www.boltscience.com/pages/he...ingwashers.htm

[farmersammm]

It's a valid test I guess. Depends on whether the nuts were actually torqued to any kind of real world value.

BUT.......................... Lock washers deform so badly, that any real torque specification is a joke. They start to move out from under the nut when torqued to required torque specs.

You'll notice that any nuts used for critical applications......cylinder heads, spring hangers, etc.....................are either on top of a solid washer, or the washer is built into the nut itself as a one piece fastener.

[bigb]

Yes I have a bunch of those in 1/4-20 size, I needed 4 serrated ones and I had to buy 100 , Flange Nuts they are called. They make serrated and smooth both. There's also the ones with slightly domed washers that are fastened to the nuts but spin, I believe when you torque them down the pressure of the dome keeps tension against them, I've seen them on lug nuts. I've grown partial to Nylocks on stuff I don't want to fall apart.

[Lis2323]

I'm kind of partial to Nylocks for certain projects also.




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[SlowBlues]

Great, and interesting information.

Nylocks and/or locktite myself.

I never trusted split washers but will use them in kits that come with them.

[12V71]

Personally, I've never had much use for split lockwashers except for "soft" joints using gaskets, etc. the spring tension seems to help hold the clamp load. In a "hard" joint even a properly torqued plain nut with hardened washers is better. Flange nuts and bolts are the stuff for truck frames, beaten down good and tight they will never loosen.
In the 80's I worked for a company that did plenty of heavy equipment work, our shop manager was a guy with a degree and zero real time experience. He caught 3 of us installing cutting edges on a D9 dozer blade and flipped out because we weren't using split locks. I personally grabbed his azz by the lapel and dragged him to the front office to see the owner, "He goes or I go" was the discussion... I explained the problem we were having in an hour long powwow, The boss offered to let the guy try laying on his back torching out junk blade frogs but he wasn't having any of that, us guys with experience were the problem according to Mr. Degree. The real suck part was I had to do his job starting the next day.

[Lis2323]

Great, and interesting information.

Nylocks and/or locktite myself.

I never trusted split washers but will use them in kits that come with them.

Same. Plus it’s the only way to keep fasteners from loosening on special assemblies that you DON’T want torqued tight.


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[SlowBlues]

They are really great in low torque applications.

the only downside is the speed.

If you have a long bolt or very fine thread it takes a long time, and a wrench the entire time, to get them off.

I always have at least a A pack of 1/4 in and 10 mm nylocks. I like to keep a few 1/4", 5/16", 8mm, and 10mm in the toolboxes.

[M J D]

Nylock nuts are decent for many applications but the real deal is either top lock or the locknuts with the small square staked section. In my climate it doesn't take long for nature's loctite to take over rendering just about any fastener unremovable without heat or cutting

[jrporter]

In aerospace, at least where I worked, every threaded fastener had to have either a self locking feature (like a locknut) or utilize a mechanical lock (cotter pin, bent tab washer, etc). We were constantly asked why we could not use cheaper non-locking nuts and split or star washers rather then the more expensive self locking parts. We always said "sure, if they can pass the test", where the test was providing some self locking/resistance to rotation without any preload on the bolt. There aren't many split washers on airplanes.

[Albin]

Spring or split ring washers were banned by NASA on the old Space Station Freedom program back in the early 90's. I have a tech document somewhere showing they are worse than ineffective, just like the video shows. That's about the same time I stopped using them. When I find them, or they come with some kit bag, I just toss them into my 55 gallon steel crap barrel.

Can't find the NASA document, but here's Pirate4x4's BillaVista's paper on bolts. The lock washer discussion starts on page 12.


https://www.pirate4x4.com/d1/tech/bi...lts_signed.pdf

[jrporter]

In a joint, if you don't lose preload, you don't need self locking, but if you lose preload, you need it to keep from losing the fastener. Loose joints are bad, unfastened ones are worse. For extremely critical joints (single point failure) FAA regs required dual locking. Google FAR 25.607 if interested

[farmersammm]

In a joint, if you don't lose preload, you don't need self locking, but if you lose preload, you need it to keep from losing the fastener. Loose joints are bad, unfastened ones are worse. For extremely critical joints (single point failure) FAA regs required dual locking. Google FAR 25.607 if interested

Are we talking assemblies with low torque values on the fasteners, that don't adequately stretch the bolt? I've observed that fasteners that are stretched, will seldom come loose. The preload keeps everything tight. IIRC, stretching is an important consideration when establishing torque values for fasteners.

[farmersammm]

The most extravagant locking methods seem to be on nuts that control preload on bearings...................which are actually mostly no preload, but have a designated endplay.........so the nut is not in stress, it's floating if it doesn't have a locking method that keeps it in place.

[12V71]

The most extravagant locking methods seem to be on nuts that control preload on bearings...................which are actually mostly no preload, but have a designated endplay.........so the nut is not in stress, it's floating if it doesn't have a locking method that keeps it in place.

Except for double lock nut hub bearings with a keeper ring on most large truck and trailer axle ends. I've also worked with some very slow speed tapered roller bearings that had a 650 Lb Ft preload torque on the nut. (LeTourneau pivot spindles on the big scrapers)

[farmersammm]

Except for double lock nut hub bearings with a keeper ring on most large truck and trailer axle ends. I've also worked with some very slow speed tapered roller bearings that had a 650 Lb Ft preload torque on the nut. (LeTourneau pivot spindles on the big scrapers)

You have to admit that there's been a sea change in truck bearings. The old school approach was allowing for about .0015 endplay on a tapered roller bearing. Today, we're looking at pre assembled cartridge type stuff from what I hear. They took the skill out of the mix I guess.

I don't find the locking methods on my Class 8 stuff anything to write home about. It's standard for the time it was built. The wheels don't fall off if you know what you're doing. Which is the rub............... a lot of morons don't know what they're doing.

[farmersammm]

As a young fella, teenager years............I thought you had to have a preload on a spindle bearing. Luckily, the bearings wore in fairly fast, and created the required endplay, without the wheel departing the area for a better climate

[farmersammm]

Here's a fun thing for y'all that don't really understand Timken bearings.

Preload your bearings on your trailer. Not gorilla tight, just snug....................

Run down the road for about a mile, and feel the hub. It'll probably be hot.

Then back off the nut, and do it right (snug, then back off one castillated notch). Run down the road the same distance, feel the hub, and it'll be markedly cooler.

A lot of spindles are set up like a micrometer. The TPI will give you a predictable endplay if you properly snug the bearing, then back off the required portion of a turn. This is why spindles are fine thread.

[12V71]

You have to admit that there's been a sea change in truck bearings. The old school approach was allowing for about .0015 endplay on a tapered roller bearing. Today, we're looking at pre assembled cartridge type stuff from what I hear. They took the skill out of the mix I guess.

I don't find the locking methods on my Class 8 stuff anything to write home about. It's standard for the time it was built. The wheels don't fall off if you know what you're doing. Which is the rub............... a lot of morons don't know what they're doing.

Yeah, a lot of the newer trucks have preload spacers in the drive wheel hubs, (they're never right when you reassemble them) And then there is the newer front hubs with double row sealed ball bearings, those you just change out with Meritor for rebuilt hubs. Crank the nut down tight and it's done.

[jrporter]

Are we talking assemblies with low torque values on the fasteners, that don't adequately stretch the bolt? I've observed that fasteners that are stretched, will seldom come loose. The preload keeps everything tight. IIRC, stretching is an important consideration when establishing torque values for fasteners.

Airframes, especially larger ones, are frequently assembled with gaps in the joints due to fit-up issues, weight of structure, and assembly error. Once the airplane gets out of the jigs and on it's wheels, and especially after flight, the gaps can close and relieve some or all of the preload in the fasteners. Free running nuts will tend to back off and end up in the bottom of the airplane or found by pilots on their pre flight inspections.

[TomA]

Cat has used fold over locks on almost everything.

[mrmikey]

I've never used lockwashers on anything, IMHO they should be banned. Depending on the application either gr8 flats and locknuts on a critical application or gr8 flats, regular nuts and Loctite............Mike

[William McCormick]

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https://www.boltscience.com/pages/he...ingwashers.htm

A couple of things to note, they put the lock washer incorrectly under the head of the bolt instead of the nut, the amount of play in the clearing hole in both cases is way too large.

I do not think too much of their adherence to the science and the reality of engineering, as it is supposed to be performed, while they do these experiments. I have seen lock washers work after a bolt had become loose because it was stretched, the lock washer kept it from coming out. Is the cut and bend in their lock washer made the right way? We are in the dark ages now so anything is possible, a fellow in China getting fifty bucks a month may not know or care which way his machine bends the washer.

Sincerely,

William McCormick

[William McCormick]

Most of the bolts used today are too small for the application they are chosen for so whatever you use could be wrong. But a split lock washer properly made works, if it is sized for the application. Ny-locks when hot spin right off. Lock tight is like crazy glue sometimes it works sometimes it does not. Flange nuts are ok to a point, and that point is when there is a deformation of the material the flange nut will not take up the slack, and the nut can spin off. That is where the split lock washer wins. But again most bolts are extremely undersized today so the whole contest is null and void.

Sincerely,

William McCormick

[William McCormick]

A properly made lock nut will tighten the nut or bolt when vibration occurs. That might be a left-hand thread lock nut.

Sincerely,

William McCormick