"anorton" wrote in message
m...

"dpb" wrote in message
...
On 6/7/2013 1:39 PM, wrote:
...

Some simply consider split ring washers to be the work of the devil.

I found this looking for a more extensive set of videos of bolts
loosening, and the test rig used.

http://www.boltscience.com/pages/jun...ringwasher.htm
...

I didn't watch the rest; I notice they didn't say anything about the
torque applied on the test. Didn't appear to me it was more than just
"snugged down" rather than really torqued, but who's to know--they
cleverly didn't the applicator so can't even judge by looking the amount
of effort or size of ratchet, etc. While it may have been optical
delusion, looked to me like the bolt turned as well which wouldn't
indicate being very tight.

I don't have any scientific evidence but 50+ yr practical use on farm
indicates to me they serve a useful purpose.

--

I was impressed by this test at first, but then I realized looking at the
graph ( http://www.boltscience.com/pages/hel...ingwashers.htm ) that
the major difference occurs only after the bolt is already too loose. The
plots diverge only after the bolt has already lost half its preload. They
really need to concentrate on the very first part of the curve where the
bolt starts to loosen. If you look closely, there is some indication one
curve is much steeper than the other at the start, but it is impossible to
tell which it is. Maybe they need to dial back the shaking a bit to be
able to measure that part of the curve better.

(following up to my own post)
What would be best would be to create a set of curves like this at several
vibration amplitudes and see if there is some level of vibration where the
lockwasher prevents any loosening, but the plain nut does not.