# lock-washers: toothed, plain split, bellville, nordlock?



## mizlplix (May 1, 2011)

no. no data.

"Star" washers are usually for medium holding applications, as they deform easily under extreme pressure. - fenders, trim, Etc.

"Split" washers are for most general applications, they do not deform until you get to Crazy tight torques.-chassis, suspension, Etc.

Most "heavy duty" applications use a plain old flat hard washer and depend on bolt stretch and bolt head friction for their clamping power.-Engine main caps, heads and rod caps.

Both Star and Split type washers scar the parent metal to a degree when holding. The third does not. If Locktite is used with the hard flat washer, it will hold well.

Yes, I ponyed up for Nordlocks because my car is stiffly sprung and prone to vibration loosening of everything. I also do not like washers that dig
into soft metals. The 5/16" size was about $.41/ea.

Miz


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## Tesseract (Sep 27, 2008)

I also don't have any documentation; that's easy enough to find on the internet, so, have at it... 

In my *experience*, however, I have learned to not use Loctite on electrical connections because it has a tendency to flow out from the threads and get in between the flat surfaces of the things to be joined. This can result in a high resistance connection with the usual dire consequences at EV amperage levels.

I have also come to prefer Belleville lock washers for joining electrical connections, both because they seem to require a consistent amount of torque to flatten out, and the light serrations don't dig out specks of metal but still grip well when torqued down. Together these two qualities make it a lot easier to achieve a good connection consistently.

My second favorite lock washer for electrical applications is internal tooth star. Least favorites are split ring and external tooth star, because both kick out specks of metal when tightened down. This is mostly a problem for connections inside of a box (ie - like a controller), though, and for larger bolt sizes the split ring lock washer is the de facto standard, though I'm not really sure why (perhaps it takes the most torque to deform?).


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## dtbaker (Jan 5, 2008)

interesting input guys, thanks for your insight. the cell terminal bolts worry me because the terminal itself is soft, and not very deep. Certainly not able to stretch a M8 steel bolt at 15 in-# of torque. lock washer of some type is absolutely needed The connections with thicker braided bus bars, or typical lugs, have very few threads engaged if you use the stock hardware.... which was why I went to using allen screw studs to be certain I had full engagement with all available threads to the bottom of the blind hole.

In this application I'm not worried about specks of metal, the prep process of flattening the terminal tops for maximum contact creates a whole LOT, although I do try to get most off when I put a dab of noalox on before the busbars. I was liking the star washers in this case BECAUSE they dig in with more points of contact than a split washer... figuring these connections should be 'permanent' as possible. 

So, thanks for input!


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## major (Apr 4, 2008)

dtbaker said:


> .... which was why I went to using allen screw studs....


Are those studs plated?


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## dtbaker (Jan 5, 2008)

major said:


> Are those studs plated?


I used Stainless...


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## onegreenev (May 18, 2012)

Here you go. I am a fan of the nordlock washer but there is another company building the same thing for a little less but still works the same.


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## major (Apr 4, 2008)

dtbaker said:


> I used Stainless...


Kool  I had a bunch of M8 plated studs fail on me due to hydrogen embrittlement. Although I don't care for stainless hardware personally, you shouldn't have that problem


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## GizmoEV (Nov 28, 2009)

FWIW, I went with brass bolts and bronze split washers on my TS pack and haven't had any problems with them over the past 2.5 years and 13k miles or so.


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## EVfun (Mar 14, 2010)

Belleville washers are traditional for electrical connections, but traditional electrical connections aren't high current in an automobile. They are supposed to be very consistent in terms of the torque needed to flatten, to the point where they can be used in stacks, facing the same way and/or opposite directions, to set spring distance and tension. 

That said, I used the longest button head stainless steel cap screws that would fit (to use as much of the terminal treads as possible) with a standard split lock washer and stainless flat washer. The washers and lock washers where the ones that came with my Thunder Sky cells. I haven't had any problems, no loose or hot connections. The little cap screws where available for a reasonable price and allen wrenches can be covered in shrink wrap except for a little 1/4 worth sticking out to engage the head. 

Button head cap screws: 6mm 8mm


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## holmesontech (Oct 24, 2012)

Have you contact a spring/washer manufacturer and asked your question or explained your situation? Many companies can make custom parts to meet your needs. I've had a lot of success with doing this.


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## mizlplix (May 1, 2011)

As a side note:

I recently installed a Mini BMS on my CALB 130AHA cells. Those Nordlocks were a little difficult to remove. They took a lot of torque to remove, then when they did turn, they slid a little and came loose with a pop. They were noticably harder than anything I had used, ever.

I torqued them when installing, and torqued them when re-installing. I used them on everything in the traction power circuit.(controller, contactor, motor, fuse, switches-ETC)

I am confident they will stay tight. They are a class act and worth the extra $45 IMHO/

Miz


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## Tyn245GL (Oct 12, 2009)

mizlplix said:


> As a side note:
> 
> I recently installed a Mini BMS on my CALB 130AHA cells. Those Nordlocks were a little difficult to remove. They took a lot of torque to remove, then when they did turn, they slid a little and came loose with a pop. They were noticably harder than anything I had used, ever.
> 
> ...


Miz, where did you position the BMS cell board ring connectors? - Are the ring connectors between the bottom of the NordLock washer and the bussbar, or did you add an additional washer? The top of the NordLock washer must be directly under the bolt head of course.

Tyn


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