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high re-use locking anchor nuts/nutplates 2
- Thread starter Jpbingley
- Start date
- Thread starter
- #3
It depends. Serrated locking washers reuse is in the range of 5 to 20 times:
Nevertheless, each reuse will entail some additional distortion of the surfaces involved.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
Nevertheless, each reuse will entail some additional distortion of the surfaces involved.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
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1
- #5
Jpbingley,
How are you going to track how many times you have re-used a nut? What will this process cost, and how much money are you going to save?
If you want to keep things simple and safe, your nuts either are not re-usable, or they are infinitely re-usable. Consider asking your safety approval people what kind of latches they like.
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JHG
How are you going to track how many times you have re-used a nut? What will this process cost, and how much money are you going to save?
If you want to keep things simple and safe, your nuts either are not re-usable, or they are infinitely re-usable. Consider asking your safety approval people what kind of latches they like.
--
JHG
LittleInch
Petroleum
Aerospace and you want to nickle and dime this??
At 20 to 50 times I think you need something different to a nut.
Or a new one every time.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
At 20 to 50 times I think you need something different to a nut.
Or a new one every time.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
EdStainless
Materials
You might look at some of the prevailing torque lock thread designs. They are more durable than most but I don't know what the limit is.
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P.E. Metallurgy, consulting work welcomed
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P.E. Metallurgy, consulting work welcomed
I looked for split and beam nuts. They look as if they would operate for a few dozen cycles, but are mostly proprietary and differ enough it's not easy to tell which would work for this application.
The best defense is a correctly designed threaded joint with sufficient elastic deformation that preload won't be lost in use. The main worry in any locking system is, if the fastener preload is insufficient that the locking element will retain the fastener and not leave an obvious clue that the fastener is no longer doing the job, leading, in some cases, to rapid fracture from fatigue.
The best defense is a correctly designed threaded joint with sufficient elastic deformation that preload won't be lost in use. The main worry in any locking system is, if the fastener preload is insufficient that the locking element will retain the fastener and not leave an obvious clue that the fastener is no longer doing the job, leading, in some cases, to rapid fracture from fatigue.
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1
- #14
Jpbingley,
If you follow proper aerospace procedure for installing threaded fasteners, the actual number of installation/removal cycles of a self-locking nutplate (or "anchor nut") is irrelevant. The prevailing torque of an interference type thread locking feature, like the ones used on self-locking nutplates, should be measured at every installation to verify it is within limits that you specify. If the measured prevailing torque is outside your specified limits, the self-locking nutplate (or anchor nut) should be replaced, regardless of how many installation/removal cycles it has.
However, if you simply want to get an idea of how many installation/removal cycles a particular type of self-locking nutplate might be good for, take a look at standard self-locking nutplate designs like MS21060 . You can find the qualification test requirements for this nutplate in MIL-DTL-25027 including installation/removal cycles and prevailing torque limits.
One thing in general to consider with interference type self-locking devices, is that small thread sizes tend to have lower lifecycle capability.
If you follow proper aerospace procedure for installing threaded fasteners, the actual number of installation/removal cycles of a self-locking nutplate (or "anchor nut") is irrelevant. The prevailing torque of an interference type thread locking feature, like the ones used on self-locking nutplates, should be measured at every installation to verify it is within limits that you specify. If the measured prevailing torque is outside your specified limits, the self-locking nutplate (or anchor nut) should be replaced, regardless of how many installation/removal cycles it has.
However, if you simply want to get an idea of how many installation/removal cycles a particular type of self-locking nutplate might be good for, take a look at standard self-locking nutplate designs like MS21060 . You can find the qualification test requirements for this nutplate in MIL-DTL-25027 including installation/removal cycles and prevailing torque limits.
One thing in general to consider with interference type self-locking devices, is that small thread sizes tend to have lower lifecycle capability.
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