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

[Roger Ruszkowski]

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