Lock Washers?????

Jiles

Well-known Member
How many of you use lock washers?
I worked in a large Aluminum Processing plant and in some departments we used lock washers and in other departments we used none.
All the machinist went to a company paid schooling about the use of lock washers and during the meeting we were asked if we had any comments.
I was the only one to make a comment out of about fifty participants.
I made the statement that the circumstances determine whether a lock washer is recommended.
I personally do not use any lock washers on any of my equipment because if it is torqued down correctly and the clearance hole is the right size, a lock washer is not unnecessary.
This got a huge response both from the schooling instructor and the participants.
I further made the comment that I only used a LW when a gasket is involved and the bolts can't be torqued.
How many LW have you seen inside an engine??
Lets say that you are attaching the hitch pins to a three point disk and you use LWs, If the washer breaks, it will fall out and you have a loose bolt.
It should also be noted that the instructor agreed with me that a lock washer should not be used again after removal because the sharp edge that cuts into the surface will, in most cases, become dull after removal.
I am not trying to start an argument just wanting some opinions.
 
I think that Loctite has replaced many applications of lock washers. I build dies, molds and fixtures, and seldom use lock washers.
 
I use them for most everything that doesn't get torqued. I reuse them also if they aren't mashed flat. It isn't the sharp edge you want from the lock washer so much as the constant push against the bolt head.

BTW, You don't see lock washers inside an engine for the same reason you don't see flat washers. Drop one on assembly and chances are that engine is going to have a catastrophic failure. Much safer to use high strength bolts and torque them to the max.
 
Lock washers dont work when a whole lot of compression is needed.

On the old stuff i use, they are a standard thing, and work well.

Try not using them from time to time, and always end up replacing that bolt when I dont....

Paul
 
(quoted from post at 17:00:13 07/30/14) I use them for most everything that doesn't get torqued. I reuse them also if they aren't mashed flat. It isn't the sharp edge you want from the lock washer so much as the constant push against the bolt head.

BTW, You don't see lock washers inside an engine for the same reason you don't see flat washers. Drop one on assembly and chances are that engine is going to have a catastrophic failure. Much safer to use high strength bolts and torque them to the max.

[b:05ff544f4c]"It isn't the sharp edge you want from the lock washer so much as the constant push against the bolt head."
[/b:05ff544f4c]
The company rep, from US Steel, agreed with me that it was!
 
If it had one when I took it apart I put one back in. If it will
vibrate when in use I put one on. I'd rather use a locknut if the
circumstances allow. Hay wagons are a good example. As
much bouncing as they do, if I don't use a locknut I usually end
up with an empty hole. Lots of newer machinery uses nuts
designed to hold on without a lock washer.
 
I use lockwashers if they came on the equipment to keep things original. I read several years ago lockwashers were obsolete and none are used by NASA. My newer book "HIGH PERFORMANCE HARDWARE" has no mention of lockwashers used as a nut retention method. Most locking is done from modifications to the nut.
 
I'm not a fan of lock washers. I use a lock nut, and lock tight. If the application is something I don't want coming loose.
 
When was the last time you saw a farmer using a torque wrench working on a piece of equipment?
Plus with old rusted bolts torque wouldn't mean anythig anyway.I use either lockwashers or self locking nuts on most things just to be on the safe side vibration especially will cause nuts or bolts to work loose.A lot different working on farm equipment than in a closed shop enviroment with new fresh bolts and steel.
 
(quoted from post at 18:15:38 07/30/14) When was the last time you saw a farmer using a torque wrench working on a piece of equipment?
Plus with old rusted bolts torque wouldn't mean anythig anyway.I use either lockwashers or self locking nuts on most things just to be on the safe side vibration especially will cause nuts or bolts to work loose.A lot different working on farm equipment than in a closed shop enviroment with new fresh bolts and steel.

[b:f914e76169]"When was the last time you saw a farmer using a torque wrench working on a piece of equipment?"
[/b:f914e76169]
Can't say that I ever have, however, I bet they know how tight to get their bolts/nuts, from experience! And the torque would be pretty close to specs.
Like with me, when I was working on a piece of equipment inside the plant, I didn't carry a torque wrench around, but I knew how tight to tighten without stripping.
Like they say--"Experience is the best teacher"
 
If all surfaces of the items being fastened are
machined, then no lock washer will be needed. The
bolt stretch will be sufficient to maintain
torque. Hardened flat washers are helpful to keep
the bolt head from digging in, damaging the
surface and giving false torque readings.

But, typically most surfaces are not machined.
They are a hot or cold rolled surface, or a cast
surface. Holes are often punched instead of
drilled, or the hole was drilled and not debured
or chamfered. All these conditions cause the
surfaces to "work" or move slightly when a load is
applied. When this happens the surfaces grind
together slightly and through the process of
"finding the path of least resistance" will seat
closer together, causing the initial bolt torque
to be relaxed. A lock washer will do 2 things,
take up the slack and prevent the bolt from
backing off.
 
I've become a huge fan of lock nuts (nylocks and distorted ones) for anything I'm fabricating myself, as long as the nut is as strong as the bolt (grade 5, 8, whatever), which many are not. However, if I'm repairing something, if there was a lock washer there when I took it apart, I put a new on there when I put it back. Maybe I tend to over tighten stuff, but I've broken a lot of split lock washers and then I've got to take it all apart again anway. They're pretty cheap insurance to just throw a new one on.
 
Point is when I'm working on a piece of equipment and trying to get it going again I'm not going to take the time to get every bolt just right like I'm building an engine.I'm most of the time going to 'torque' it with whatever impact I have handy and let it go, self locking nuts and lock washers are cheap insurance and time savers.
 
In my mind, this is a very good discussion, thank you for posting this Jiles.

I attended a training session put on by loc-tite a couple of times, once as a technician for a John Deere Dealer, and once as a technician for a Cat Dealer. During this training they mentioned that they did a study of fasteners and how many cyclic loads the fastener could handle before they came loose. They used several different combinations of fasters/washers/lock-washers. Now I do not remember all the details from this, but what I do remember is that through course of the study, they found that the fasteners held in place with a lock-washer came loose sooner than the fastener held in place with just the flat washer. The fastener that was held in place with loc-tite did not come loose during the study or if it did come loose, it took a significant amount of cyclic loads for it to come loose.

After learning this, I now throw all lock washers away and use flat washers in its place, or loc-tite if in doubt.

Jared
 
Well....it may not be that "sharp edge" that holds
the nut but if you use lock washers on your trailer
hitch balls, you will find that those sharp edges
sure do dig in when you're trying to remove them!
 


I'm still stuck on the original post.

" I personally do not use any lock washers on any of my equipment because if it is torqued down correctly and the clearance hole is the right size, a lock washer is not unnecessary."

Is this a trick question?
 
Use them all the time if a bolt is not used directly on an engine block or is a torqued down type nut/bolt.
They do hold cause that is what they were meant to do.
Cant recall ever loosing a fastener mounted with a lock washer even on heavily vibrating machines.

Lock nuts to me can still loosen much easier than using a lock washer and are a bigger PITA to remove. You just wont lose the lock nut cause it will stay on the bolt even though the bolt is loose in its mount.

Now a "star" washer is a whole other subject.


mvphoto9647.jpg
 
(quoted from post at 00:23:26 07/31/14) In my mind, this is a very good discussion, thank you for posting this Jiles.

I attended a training session put on by loc-tite a couple of times, once as a technician for a John Deere Dealer, and once as a technician for a Cat Dealer. During this training they mentioned that they did a study of fasteners and how many cyclic loads the fastener could handle before they came loose. They used several different combinations of fasters/washers/lock-washers. Now I do not remember all the details from this, but what I do remember is that through course of the study, they found that the fasteners held in place with a lock-washer came loose sooner than the fastener held in place with just the flat washer. The fastener that was held in place with loc-tite did not come loose during the study or if it did come loose, it took a significant amount of cyclic loads for it to come loose.

After learning this, I now throw all lock washers away and use flat washers in its place, or loc-tite if in doubt.

Jared
heir findings are not much of a surprise since they are trying to sell the product after all.I like the star washer comment,best holding washer IMHO,and I have seen those inside of engines!lock washer or no lock washer? Hmmm...If I don't want it to come loose I use a lock washer,I've tried without one in a pinch, don't work.
 
I used to test fasteners (among other metal
items...) for the State of Kansas. We found that a
split lock washer only works "as advertised" around
20% of the time. Also - it is only designed to
"work" when it is LOOSE. Thirdly - once one is used
ONCE, it is TOAST. No matter how good it looks, it
is folley to reuse one.
 
A few shops still specify split lock washers, most haven't for decades. I will still use split lock washers where pieces must be finely adjusted into position by hand. A lock washer maintains some bolt tension and some friction between the joined parts. That makes it easier to just crack the bolts loose and tap the joint around without it being completely loose. Jack screws on/or dial indicators help too.

I'm under the impression split lock washers were most useful when wood was still used in machines. As the wood under a bolt softened or compressed, tension on bolts could be quickly lost. A split lock washer is a short spring with 1/32 or more travel, it would maintain some tension on the bolt as the wood compressed.

On farm machinery made of soft steel, where components bend and flex, and the fasteners are all softer bolts, lock washers can work. Between hardened steel and grade 8 bolts, lock washers are about useless.
 

I would agree the bolt(s) must be properly torqued. This means that the bolt stretch generates a clamping load greater than the bolts(s) will ever see in service. If this is true then a locking device is not required and the bolt(s) should not lossen or fail in service.

Now for the above to be true a person(s) needs to determine the maximum service loads, select the number of bolts/bolt pattern and the torque value to insure a clamping load greater than the service loads. The fit up and bolt(s) mating surfaces must to proper to insure the torque wrench reading is indeed the torque on the bolt.

In summary a properly engineered joint should not require a locking device, for example, engine connecting rod bolts. In my experience it was common for bolts to lossen on farm machinery. This suggests that the time and expense to determine service loads and properly design the bolted joint did not occur. It is for these non-designed bolted joints that locking devices can be of benefit.

In summary a locking device can provide a reliable joint for non-critical applications and save the time and expense of detail design.
 
My boss used to work in a Caterpillar engineering
group. He said that in that department the use of
any locking device be it a lock washer, thread
locker, lock nut, etc, was considered a "Band-aid"
since it meant the bolted joint was insufficiently
designed. In our engineering department we use a
lot of high grade hex flange lock nuts but we
never use lock washers except in very unique
situations. We use hardened flat washers under
nearly any screw or nut that doesn't have a built-
in flange to allow for a more precise bolt stretch
when torqued to a given level. Like you said, it
is the bolt stretch and resulting clamp load that
keeps things tight. You can drastically improve
the integrity of a joint by adding a spacer and
using a longer bolt to get more stretch for a
given clamp load.
 
Jiles,
I have reused lockwashers, used no lc, bought grade 2,5,8 lockwashers. Is there a metastudy done on this topic. Also, used loctite red, blur and green loctite.
I have a sectioned off part of my shop with a mill, lathe, surface griner.etc
The environment in there is very different from my farm equipment.
Farm equipment is exposed to the elements, different vibrations and stresses. Help, how do you use lockwashers in a not machine shop environment. A lot of bolts are not clean and oiled
 
It depends. In the examples that you give where pieces are bonded, touching, torque specs tend to cover it. But, where they are not, such as two tractor frame rails that are several inches, maybe even a couple of feet apart where there can be a long bolt for hanging, say a belly mower, then you cant torque them so much because you can cause the rails to want to draw towards each other, out of shape. In a case like that, lock washers would work best because you want to just lock the bolt in place.

Again, there are examples, applications where one works, the other will not, and could be harmful. I know this...I've used lock washers where bolts are torqued at high pressures and broke the lock washers, obviously a no no.

Great subject, topic. Thanks.

Mark
 
For Structural applications using A325 and A490 bolt assemblies, lockwashers are NEVER used. Torquing alone is sufficient.
There are such things as high-strength lockwashers, but they are extremely rare. So if you are using anything other than a grade 2 bolt, I wouldn"t use it. Nyloks or loctite are better in my book.
 
since early last year when i first started getting my old tractors and been working on them, i have pulled a lot of things apart and found a lot of broken lock washers, the bolts were still there, and i had some mystery bolts that were gone. this post has got me thinking, it used to be if there was one before, it gets one again. then when they came out with nylocks, i thought it was the best thing since sliced bread, i have replaced nuts with nylocks many times and didn't have to worry about it again. of course i always keep red and blue locktite around and use them all the time. i still use lock nuts for non tension applications for added assurance.
as far as lock washers go inside of a motor, yes, i have seen it, we have a car that the timing chain failed and caused the valves to get bent all to he!!, well, the first instructions dennis got were wrong, he torqued it down and a year latter we were wondering where all the water was going, pulled the head off and the gasket had a hole eaten thru it. the second time the instructions were x pounds and then 3/4 turn after that, no problems since, the head bolts have lock washers on them.
 
Auto manufacturers have nearly eliminated all washers, not just locks. For those case where a washer is required, it is made a captive part of the bolt or nut so it doesn't have to be handled separately. Locking is normally done using a locking compound pre-applied to the fastener threads.

I generally don't use lock washers on my own stuff. If I'm concerned about a fastener loosening, I'll use a self-locking nut or Loctite.
 
M-MAN, in fact they do use flat washers inside engines. Placing a washerless head bolt, or nut, on a alloy head results in galling the head and a lose of torque. The washers are not run of the mill stamped steel ones from corner home store, they are machined and hardened with very tight tolerances.
We also used ARP machined washers when building engines with blowers.
 

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