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  #11  
Old 07-30-2014, 12:24 PM
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az_gila az_gila is offline
 
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Quote:
Originally Posted by bhassel View Post
Try Boelube if it's really tight to get the screw into the nutplate.

Bob
That's a good technique every time for the first use of a screw into a new nutplate.
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  #12  
Old 07-30-2014, 07:44 PM
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Washer stacks work and I used that technique sometimes but I also had a supply of 1/4 inch long phillips head #8 screws. I preferred them over the washer stacks.
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  #13  
Old 07-30-2014, 08:19 PM
BobTurner BobTurner is offline
 
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Quote:
Originally Posted by rzbill View Post
Washer stacks work and I used that technique sometimes but I also had a supply of 1/4 inch long phillips head #8 screws. I preferred them over the washer stacks.
This is okay but you should paint all the heads orange so you don't leave them there by mistake. Otoh a stack of washers is hard to miss.
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  #14  
Old 07-30-2014, 08:53 PM
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Quote:
Originally Posted by az_gila View Post
The prevailing torque is the only requirement I found in several Mil Specs I checked. I could find no use limit numbers...
It is a material specification. Just as the surface finish, hole diameter, material, rivet hole dimension, etc.

The product must "meet or exceed" X cycles and retain run on torque....

Similar to the TBO on a Lycoming, if you can get more out of it, that's great!
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  #15  
Old 07-30-2014, 09:18 PM
BillL BillL is offline
 
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By accident I found that the nut plate AND the screw wear in with cycles. I noticed that the hardware store stainless #6, #8 screws wear in pretty quickly. Then using a proper aviation screw the install friction torque jumps significantly.

You might experiment with this to get a better feel for it.
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  #16  
Old 07-30-2014, 10:44 PM
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Quote:
Originally Posted by Toobuilder View Post
It is a material specification. Just as the surface finish, hole diameter, material, rivet hole dimension, etc.

The product must "meet or exceed" X cycles and retain run on torque....

Similar to the TBO on a Lycoming, if you can get more out of it, that's great!
The older MS21047 specs do not seem to have any usage requirements -

http://www.everyspec.com/MS-Specs/MS...47F.034285.pdf

Did they add them when they became SAE specs?

Or are you referring to later, fancier, more expensive nutplates than we typically use?

The MS21047 -

http://aircraftfast.com/thumb.php?im...IF&w=300&h=300
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Half completed RV-10 QB purchased
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Grumman Tiger N12GA - flying
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  #17  
Old 07-31-2014, 04:28 AM
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rzbill rzbill is offline
 
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Quote:
Originally Posted by BobTurner View Post
This is okay but you should paint all the heads orange so you don't leave them there by mistake. Otoh a stack of washers is hard to miss.
Thats true. In my case they were commercial grade. Not sure what finish (possibly black oxide) but they were easily different than cad plated screws.
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Bill Pendergrass
ME/AE '82
RV-7A: Flying since April 15, 2012. 850 hrs
YIO-360-M1B, mags, CS, GRT EX and WS H1s & A/P, Navworx
Unpainted, polished....kinda'... Eyeballin' vinyl really hard.
Yeah. The boss got a Silhouette Cameo 4 Xmas 2019.
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  #18  
Old 07-31-2014, 08:21 PM
jarhead jarhead is offline
 
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I've never seen any reference to nutplate replacement after x cycles, in 20 years of both .civ and .mil helicopter maintenance, on multiple models from every "major" helicopter OEM (except the Russian OEMs). Plenty of references to loss of run-on torque, prevailing torque, and locking ability... but never "replace nutplates after x remove/install cycles".

Nutplates are an "on-condition" item, just like common panel hardware.
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  #19  
Old 07-31-2014, 08:31 PM
paul mosher
 
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I think they are confusing fiber lock nuts with metal nutplates.
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  #20  
Old 08-01-2014, 09:26 AM
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Toobuilder Toobuilder is offline
 
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Yes, they are "on condition"...

Yes, there is a material specification that states the nut plate must meet or exceed xx cycles. Don't confuse this "minimum specification" with a "recommended replacement schedule". If they meet run on torque, they are serviceable.

...but the point remains they do wear out eventually. We replace them by the thousands in depot.
__________________
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
______________
Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
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