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Are lock washers graded?


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This photo is of a Lock ring washer from a GM car, and has a knurled pattern on the outer edge. Many if not most of the lock washers on this car have this pattern as have other GM cars (Buick’s) that I have stripped for parts. 
 

Is this a higher grade washer than a washer wIth a smooth outer perimeter that I would get at the hardware store?  Is there a source for these washers?0F9CC6F6-15AB-4F9D-87E7-94A0D35EACF9.thumb.jpeg.b8029ab97e43d0d5d9d02704d0f380c0.jpeg

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Having sold fasteners for 25 years, I don't recall any grading on standard lockwashers. There are some specialty types used in industry, but it's highly unlikely that you would ever see that type hardware in a hardware or big box store. You'll see different shades of plating on some hardware, but color in itself, is not indicative of grading.The little marks you see are most likely from the manufacturing process. Split lockwashers are designed to compress with slight tension and should only be used once.

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There are plain and plated lock washers for grade 2 bolts and hardened lock washers intended for grade 5 and grade 8 bolts and cap screws.  The hardened ones may have clear or yellow zinc coatings, but are frequently yellow. 

 

That said, there is a lot of data that says lock washers will not prevent a bolt from loosening and may even make it worse.  See boltscience.com. To really lock the bolt to the nut or threaded part, use Loctite, either the blue or red variety depending on whether you will want to remove the bolt without heat.  A Nyloc nut or two nuts locked together also works.

Edited by Gary_Ash (see edit history)
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Just to add a note. Most stores will carry grade 2, grade 5 and grade 8 bolts and nuts. Again, plating color is not always indicative of grade. Low carbon fasteners, such as grade 2 are usually in raw steel but they can be found plated. The standard low carbon lockwasher can be found plain, plated or black. Grading on American fasteners, and unfortunately, I don't believe any are made in this country anymore, is as follows: Grade 2 will have no head marks or 1 raised or indented dash mark, Grade 5 will have 3 raised or indented dash marks and Grade 8 will have 6. At least that's how it was a time back. Most Grade 5 and Grade 8 will be black, but can also be found in zinc and yellow zinc plating. Fasteners for sale in hardware stores are usually colored to help distinguish grade but mostly for protection and appearance. You may find Grade 8 lockwashers along with the grade 8 bolts but there is no real advantage to using them on standard or grade 5 fasteners. Stainless fasteners are graded by their ferrous content, like 304 for standard bolts, which may have a slight magnetic attraction and may rust if filed with a steel file. 304 SS is a little harder than Grade 2 but less than Grade 5 in strength. This is the stainless most commonly found in hardware stores. 18-8 or 316 have less ferrous content so they're more rust resistant and are a little harder than the 304 SS. You should never use standard stainless bolts in a strength application. You always have the option of using star type lockwasher which will do a good job too, but they are not available in stainless, that I know of.

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On 10/12/2020 at 6:23 PM, Gary_Ash said:

There are plain and plated lock washers for grade 2 bolts and hardened lock washers intended for grade 5 and grade 8 bolts and cap screws.  The hardened ones may have clear or yellow zinc coatings, but are frequently yellow. 

 

That said, there is a lot of data that says lock washers will not prevent a bolt from loosening and may even make it worse.  See boltscience.com. To really lock the bolt to the nut or threaded part, use Loctite, either the blue or red variety depending on whether you will want to remove the bolt without heat.  A Nyloc nut or two nuts locked together also works.

Now you tell me after I spent thirty minutes looking for a couple of washers in my spare parts bin today! Lol. Zeke

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On 10/12/2020 at 5:23 PM, Gary_Ash said:

  That said, there is a lot of data that says lock washers will not prevent a bolt from loosening and may even make it worse.  See boltscience.com. 

... 

two nuts locked together also works.

 

Yes, Gary is right. In severe, or safety applications, I use double nuts, and this is often a better way of removing studs, as well. Tighten one nut against the other and turn the lower/ closer to the base nut to remove a stud.

Edited by Marty Roth (see edit history)
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On 10/12/2020 at 6:23 PM, Gary_Ash said:

 

That said, there is a lot of data that says lock washers will not prevent a bolt from loosening and may even make it worse.  See boltscience.com. To really lock the bolt to the nut or threaded part, use Loctite, either the blue or red variety depending on whether you will want to remove the bolt without heat.  A Nyloc nut or two nuts locked together also works.

Adding to what Gary stated.....You do not find lock washers in the aviation industry. They use a lot of polymer-insert nuts (Nyloc), pal nuts (thin stamped nuts used as a “double nut”) and safety wire. 


In our old car hobby, and in keeping with original looks, I also use Loctite with a lock washer in areas of concern. Although not necessarily recommended for fasteners, I use Loctite Retaining Compound in some applications as it acts more like a Nyloc nut - lots of drag rather than just high breakaway torque.

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On 10/25/2020 at 6:23 PM, David Houston said:

This is a bit "out of left field" but there are some really cool lock washers which work in a slightly different way. They are from NORD-LOCK and you can find them on Amazon and places. They almost work too well sometimes and are pretty hard to get OFF once you get them on. 

Interesting: https://www.nord-lock.com/nord-lock/products/washers/

 

 

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