Using lock washers

[papakb]

The general trend today is to go away from lock washers when assembling mechanicals. Between KEP nuts, Aviation nuts, and Thread Locking compounds they've been replaced as janother unnecessary cost reduction. Most engineers will tell you that lock washers shouldn't be reused although most people do tend to reuse them all the time. After their first use the sharp tangs that actually provide the locking action fold away and become less helpful with each reuse. Stick with Loctite Blue (medium strength) unless you never want it to come apart again and then Red Loctite (high strength) is the way to go. I often use Green Loctite on fasteners because of it's wicking action where it can be applied to already assembled fasteners.

 

[Action]

Become less helpful with each reuse? You dont reuse lock washers....

 

[Lothar]

Come to think of it, I don't really like lock washers and don't believe they work very well. I just gained a whole column in my short of space bolt bin. Thanks for the idea!

 

[Mullaney]

The general trend today is to go away from lock washers when assembling mechanicals. Between KEP nuts, Aviation nuts, and Thread Locking compounds they've been replaced as just another cost reduction. Most engineers will tell you that lock washers shouldn't be reused although most people do tend to reuse them. After their first use the sharp tangs that actually provide the locking action fold away and become less helpful with each reuse. Stick with Loctite Blue (medium strength) unless you never want it to come apart again and then Red Loctite (high strength) is the way to go. I often use Green Loctite on fasteners because of it's wicking action where it can be applied to already assembled fasteners.

.
I'm definitely not an engineer, but the one I used to work for claimed "flat washers only" no lock washers - ever.

A lot of the things I built for him are still around.
Found some old blueprints with a sub-note on each page "no lock washers"

I asked about that one time and his answer was that they are more brittle than regular washers.
The brittle break more easily. When broken the nut is no longer against what it was holding...
Creating your very own unplanned failure

 

[Coug]

.
I'm definitely not an engineer, but the one I used to work for claimed "flat washers only" no lock washers - ever.

A lot of the things I built for him are still around.
Found some old blueprints with a sub-note on each page "no lock washers"

I asked about that one time and his answer was that they are more brittle than regular washers.
The brittle break more easily. When broken the nut is no longer against what it was holding...
Creating your very own unplanned failure

My college diesel instructor was also against lock washers. He said he had never had a nut on a flat washer come loose where a lock washer would have done any better. Properly torquing the nuts was the important part.

 

[TechnoWeenie]

Are you talking internal/external tooth star washers, or split washers?

 

[Coug]

Are you talking internal/external tooth star washers, or split washers?

split washers.
The internal/external are just for bolts that need a good electrical connection as far as I've ever been told.

 

[TechnoWeenie]

split washers.
The internal/external are just for bolts that need a good electrical connection as far as I've ever been told.

There are situations where I use both a star washer and split washer, but never just a split washer. Internal tooth star washers grab, and they're great when you don't have kep nuts and need to tighten something down with minimal access from the other side. The split washer will put tension on the star washer, allowing it to grab, and tighten..

 

[frank8003]

All expendable parts lists I have seen and in the TM's themselves instructs to discard washers and use new ones.
See example TM 9-2320-361-24-2 WP 0470 00-2
mandatory replacement parts

Also used a lot of Belleville washers in powerplants.
belleville washer/spring

 

[Guyfang]

Become less helpful with each reuse? You dont reuse lock washers....

What you should have written was, "You SHOULD NOT reuse lock washers". But sadly, way to many folks do. When I worked on turbines, we did not reuse ANY fastener, nor lock washer. And a torqe wrench was required for everything.