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Washer stacking
Posted: Mon Oct 24, 2016 4:27 pm
by bagarre
Not to revive an old argument or beat a dead horse but,
I just had to share what I found on 95D's gear leg. I got a chuckle.
It wont be like this when it goes back together.
washers.jpg
Re: Washer stacking
Posted: Mon Oct 24, 2016 4:38 pm
by johneeb
All those washers and the near bolt does not have at least 1 1/2 threads showing!
Re: Washer stacking
Posted: Mon Oct 24, 2016 4:46 pm
by bagarre
johneeb wrote:All those washers and the near bolt does not have at least 1 1/2 threads showing!
LOL. I had already started to take that bolt off when I though to take a photo for posterity.
Re: Washer stacking
Posted: Mon Oct 24, 2016 4:55 pm
by c170b53
Oooh...backing plates.....
Re: Washer stacking
Posted: Mon Oct 24, 2016 5:03 pm
by bagarre
c170b53 wrote:Oooh...backing plates.....
To be accompanied by the polished wheel pants I have
Re: Washer stacking
Posted: Thu Oct 27, 2016 11:10 am
by MoonlightVFR
Puzzling, why stack washers?
If the bolt was too long what bolt should be installed?
Was someone trying to adjust caster or camber?
Regards
Re: Washer stacking
Posted: Thu Oct 27, 2016 11:52 am
by Bruce Fenstermacher
MoonlightVFR wrote:Puzzling, why stack washers?
If the bolt was too long what bolt should be installed?
Was someone trying to adjust caster or camber?
Regards
Answering the questions in reverse:
3. Yes, likely they were adjusting camber or caster or perhaps just replacing an axle.
2. Best practices specify a shorter bolt should have been installed.
1. Because bolt lengths are standard but those items dimensions the bolts are being used with rarely fit precisely within a standard grip length, washers are installed so nuts do not bottom out on the end of the thread before the bolt is properly tightened. Best practices, which mechanics are obliged to follow by the FARS unless other wise allowed, says that only so many washers should be stacked and only so much thread should protrude through the nut yet there is also a minumum threads showing through the nut standard.
As manufacturers do not have to follow best practices, over the years, specially in older aircraft, you can find situations where one can not acquire a bolt whose grip length is such that one can meet all the best practices of stacked washers and threads showing. Back then, they used common sense, when stacking washers and how many threads protruded through the nut, something not found in abundance today where everything has to be spelled out in a book or manual with no room for common sense.
David's examples show someone who did not follow best practice nor did they get as close as they could have.