Lock washer performance worse than no washer at all?

L

lowpitch

Well-known member
I recently got some 3/8" internal tooth lock washers thinking they should help with 1/4" jacks coming loose over time but it seems they actually perform worse when it comes to rotational forces. I use Rean NYS229 and Lumberg KLBM 3 jacks exclusively and both seem to have better grip without lock washers, that is if I tighten them enough it's almost impossible to rotate them by hand after the fact. Is this anybody else's experience or are my washers just shit? Or do these only help with vibrational forces over time, but not if any actual torque is applied? I put these directly between jacks and enclosure on the inside and sand away any residual paint inside the enclosure beforehand, so contact is with the bare aluminum directly.

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Yeah, it's true. The spring force they put on the nut acts as a lubricant for the rotational force that undoes the nut

I just tighten mine up with a regular washer. When I mount my jacks, I do it so the inner housing of the jack rests against a wall of the enclosure so that if they do come loose, tightening it isn't a big deal. Same with the footswitch

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falco_femoralis said:
Yeah, it's true. The spring force they put on the nut acts as a lubricant for the rotational force that undoes the nut

I just tighten mine up with a regular washer. When I mount my jacks, I do it so the inner housing of the jack rests against a wall of the enclosure so that if they do come loose, tightening it isn't a big deal. Same with the footswitch

CRMEuUk.jpeg
Click to expand...
Good solution. I don't mind jacks coming loose for pedals I build for myself, but pedals I actually sell I'd rather turn bullet-proof as much as possible, that was the initial idea behind the lock washers.
 
I don't think toothed washers are optimal for this. They really need soft surfaces, like copper bus bars, and I don't think the excell under vibration.
Honestly, I think the limited thread count on most jacks is the weak link.
Both the nys and klbm don't have a great flush face to lock into/onto either.
Nordlock or a pair of Belleville washers may be better options.
I've experimented with both in pedals and they seem fine but not enough experience to say anything conclusive.
We use nords a lot on our MRIs in vibration prone environments.
But again, the clamping for e of the single thread or so in the nuts used on jacks is minimal.
Also, with Belleville, your drilling tolerance would need to be pretty tight.
 
jwin615 said:
I don't think toothed washers are optimal for this. They really need soft surfaces, like copper bus bars, and I don't think the excell under vibration.
Honestly, I think the limited thread count on most jacks is the weak link.
Both the nys and klbm don't have a great flush face to lock into/onto either.
Nordlock or a pair of Belleville washers may be better options.
I've experimented with both in pedals and they seem fine but not enough experience to say anything conclusive.
We use nords a lot on our MRIs in vibration prone environments.
But again, the clamping for e of the single thread or so in the nuts used on jacks is minimal.
Also, with Belleville, your drilling tolerance would need to be pretty tight.
Click to expand...
I wasn't aware of either of these types of washers. I'll give them a try if I can find some, although your point about the minimal thread count on standard jack nuts being an issue seems very valid. Maybe the answer is moving to PCB-mounted jacks. The same concerns apply but in my mind rotational forces should be less of an issue with these. But then again solder joints cracking might become more of a problem over time.
 
When I don't want a small nut like this to come undone, I put a drop of paint on it.
Having some Scottish genes, I use fingernail polish - more specifically, a color that was on sale...
Very easy to dispense, and close up for the next use.
 
lowpitch said:
Good solution. I don't mind jacks coming loose for pedals I build for myself, but pedals I actually sell I'd rather turn bullet-proof as much as possible, that was the initial idea behind the lock washers.
Click to expand...
All you need to do is conduct a study using your own pedals as a sample. How many of them have you had to retighten a year down the road?

The only thing I've had to retighten are power jacks - both the bigger and smaller type, as they do not have a retaining washer, just a thin nut. So for my commercial builds, I now hot glue the back of the jack in place to prevent the nut from loosening.

If I'm using a small power jack, I locate the small power jack to the top of the back such that one of the faces of the retaining nut sits against the top of the enclosure, effectively becoming a captive nut. Then it receives the final torque with a pair of pliers from the outside

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Lastly, I offer a 1 year warranty on my pedals so that if there ever is an issue, I'm able to correct it and update the pedal to any newer methods I'm able to develop.
 
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