[R-390] reply to Chris's loose screws

[Chris]

By conventional wisdom, that split washer should be be under the head of the screw, not the nut as it is held captive and not allowed to turn more than a few degrees by the clamp.  

By more modern knowledge, that split washer does basically nothing to prevent the joint from loosening-  Point in case, how many split lock washers are used on that new car that mysteriously doesn't vibrate apart?  VERY few washers of any kind are used, with exception of electrical grounds.  

For those integrated in the real facts about lock washers, and hardware in general, below is one of many very interesting an enlightening articles out there:

http://www.boltscience.com/pages/vibloose.htm

Regards, 
Chris 

Sent from my outdated iPhone wireless thingy

On Mar 2, 2014, at 5:55 PM, Roger Ruszkowski <flowertime01 at wmconnect.com> wrote:

> 
> Chris, You asked.
> 
> Can anybody tell me WHY they used split lock washers under the nuts on later  units?? 
> 
> A lot of R390's were mounted in mobile vans and got shaken down the road.
> 
> The idea was the tension of the lock washer in the stack would keep the
> bolts from vibrating loose.
> 
> Time after time I would ship racks of stuff from San Diego to Fullerton California (100 miles)
> or cross country to Lynchburg Virginia and back.
> The stuff would work in San Diego, 
> Arrive in many loose pieces.
> Get put back together again.
> Operate through shock and vibration tests just fine.
> Get shipped home to San Diego and arrive in parts again.
> Get put back together and work again.
> 
> When you put things in trucks even air ride and setting on shock mounts
> they fall apart.
> 
> How our autos stay together for ever amazes me every day.
> 
> Roger AI4NI
> 
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