Extra washers under head or under nut?

alpinelakespilot2000 · #1 07-10-2006, 11:25 AM

If extra washers are necessary because a bolt/washer call-out is SLIGHTLY too long, should the extra washer(s) be put under the nut or under the head of the bolt? Is there a standard practice? I know that AC43.13 specifies not to use more than 1/8" of washers total, but if you do need to add a washer, is it OK to add it either location depending on ease of installation? Thanks.

Jekyll · #2 07-10-2006, 11:30 AM

Mox nix.

Governed by interferance with other structure.

Jekyll

alpinelakespilot2000 · #3 07-10-2006, 11:33 AM

Thanks Jekyll for the quick reply. Need to use it right now.

pierre smith · #4 07-10-2006, 12:26 PM

Preferably under the nut since you're not supposed to turn the bolt if you can help it. Turning the bolt can scratch it and this is where a stress riser/crack could develop. The washer will act as a scratch deterrent when you tighten the nut,
Regards,

alpinelakespilot2000 · #5 07-10-2006, 06:07 PM

Yes, obviously a washer goes under the nut. I'm talking about when an extra washer is required because the bolt is slightly too long (and when the next shorter bolt would be too short).

Since the shoulder of the bolt is too long, I can put the washer on either end of the bolt and still have only shoulder (and no threads) going through the material. That's why I need the extra washer in the first place.

Also know that tightening the nut is better than the head. However, when the head must be turned (there are a number of places where it has to be), it is OK to do so, but a washer should be under the head in that case.

Have I missed anything?

lrfrey · #6 07-11-2006, 07:00 AM

Nope, and three washers max or get a different bolt.

Larry