Jvvmusme
Well-known member
What is the differnce between spring lock washers and tooth (internal and external) lock washers
For what use were intended ?
For what use were intended ?
Spring lock washers vs Tooth lock washers
- Thread starter Jvvmusme
- Start date
djkeev
Well-known member
Lock washers Literally "bite" into the nut and into the metal being bolted together. The cut spring washer if you look at it is angled to prevent the nut from backing off. When I was at my latest NAARSO training courses it was mentioned by the Fastenal representtive that these lock washers are under fire as to their effectiveness.
The internal and external "star" washers also dig into the nut and material being bolted. What is the difference? Well the internal one looks better when fastened together, they also have less digging in surface area. The external ones have more grip area but they can be "unsightly" when in use with the little tentacles sticking out.
They also make the star washer with both internal and external stars.
You also overlooked the wave lock washer used on a lot of German products. They simply push against and hopefully from the added spring pressure they apply, prevent a nut from backing off.
Dave
The internal and external "star" washers also dig into the nut and material being bolted. What is the difference? Well the internal one looks better when fastened together, they also have less digging in surface area. The external ones have more grip area but they can be "unsightly" when in use with the little tentacles sticking out.
They also make the star washer with both internal and external stars.
You also overlooked the wave lock washer used on a lot of German products. They simply push against and hopefully from the added spring pressure they apply, prevent a nut from backing off.
Dave
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tcianci
Well-known member
The internal/external tooth washers are more commonly used in grounding situations than in anti-loosening applications although I have seen them used to just keep things from getting loose. The tooth type washers penetrate paint to provide an adquate electrical connection.
sberry
Banned
I toss a LOT of lockwashers in the scrap on eqipment, use a flat under the turned element and always lube nuts bolts threads with penetrating spray.
Air_Cooled_Nut
Well-known member
And you overlooked the serrated washer, commonly found under the heads of German CV bolts
nehog
Well-known member
Toothed (both internal and external) are designed for electrical conductivity, not for locking purposes. Typically found on ground screws, though can be used on any type of terminals that have screws or nuts.
abstamaria
Well-known member
Jose, there is a joke that Lotuses shed parts while standing on the driveway. So beginning 1977, when I bought and resolved to restore a 1969 Lotus Elan, I decided to learn as much as I could about nuts and bolts. I must have read half a dozen books on the subject, but the best was Carroll Smith's "Prepare to Win," in which he talks about fasteners, rivets, keeping things together, etc. Very readable, humorous, and highly recommended.
On our topic, he said "lock washers don't [lock]." As suggested above, Smith says throw those lock washers away, use a flat washer, and torque correctly. Use locknuts, safety wire, or Loctite to keep things fastened. That's exactly what I did. Smith has written other books, all of which I recommend too. Smith was chief mechanic with Carroll Shelby's 60s racing team, including I believe Le Mans.
The exception would be the toothed washers that nehog mentions above for the reason he states. For keeping the nut or bolt on, however, use Locktite or similar.
Andy
On our topic, he said "lock washers don't [lock]." As suggested above, Smith says throw those lock washers away, use a flat washer, and torque correctly. Use locknuts, safety wire, or Loctite to keep things fastened. That's exactly what I did. Smith has written other books, all of which I recommend too. Smith was chief mechanic with Carroll Shelby's 60s racing team, including I believe Le Mans.
The exception would be the toothed washers that nehog mentions above for the reason he states. For keeping the nut or bolt on, however, use Locktite or similar.
Andy
You also overlooked the wave lock washer used on a lot of German products. They simply push against and hopefully from the added spring pressure they apply, prevent a nut from backing off.
Are we talking about products from Wolfsberg and Stuttgart or did anyone else use these?
Are we talking about products from Wolfsberg and Stuttgart or did anyone else use these?
A lot depends on how critical a failure would be.
There are tons of machines held together with “split” lock washers.
They seem to work fine in most applications.
But they don’t even use anything on lug nuts.
Go figure.
Switch to high vibration locations and you will see cross drilled bolts and maybe castellated nuts with clips. ( I grew up learning to call them “hair pins.” But I doubt many guys know what a hair pin is now days.)
More often cotter keys. But they cannot be reused.
Think wheel bearings on a spindle.
Go into aircraft and even dead end bolts have their heads cross drilled and safety wired.
There is a real science to it.
There are tons of machines held together with “split” lock washers.
They seem to work fine in most applications.
But they don’t even use anything on lug nuts.
Go figure.
Switch to high vibration locations and you will see cross drilled bolts and maybe castellated nuts with clips. ( I grew up learning to call them “hair pins.” But I doubt many guys know what a hair pin is now days.)
More often cotter keys. But they cannot be reused.
Think wheel bearings on a spindle.
Go into aircraft and even dead end bolts have their heads cross drilled and safety wired.
There is a real science to it.
They are also used on flywheel bolts.
Alan Douglas
Well-known member
As I remember reading somewhere, if a split lock washer does anything, the joint has already failed.
Probably way overkill for most people / applications, but we'we got a few customers spec'ing in these things. They get very pricey when you get into the high nickel stuff.
http://www.nord-lock.com/
http://www.nord-lock.com/
abstamaria
Well-known member
Tooth lock washers
but why is that, Nehog? Why would toothed washers improve electrical conductivity?
Andy
but why is that, Nehog? Why would toothed washers improve electrical conductivity?
Andy
nehog
Well-known member
Re: Tooth lock washers
They 'dig' past surface paint, dirt, and oxidation (especially important when dealing with aluminum).
They 'dig' past surface paint, dirt, and oxidation (especially important when dealing with aluminum).
http://www.boltscience.com/pages/helicalspringwashers.htm
the page seems to be missing the beginning, but you get the point from the chart. Most newer cars don't use split lockwashers- they've gone to flange head bolts and nuts.
the page seems to be missing the beginning, but you get the point from the chart. Most newer cars don't use split lockwashers- they've gone to flange head bolts and nuts.