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07-30-2014, 12:24 PM
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Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
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Quote:
Originally Posted by bhassel
Try Boelube if it's really tight to get the screw into the nutplate.
Bob
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That's a good technique every time for the first use of a screw into a new nutplate.
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
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07-30-2014, 07:44 PM
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Join Date: Nov 2005
Location: Asheville, NC
Posts: 2,692
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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.
__________________
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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07-30-2014, 08:19 PM
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Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,797
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Quote:
Originally Posted by rzbill
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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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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07-30-2014, 08:53 PM
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Join Date: Jul 2009
Location: Mojave
Posts: 4,652
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Quote:
Originally Posted by az_gila
The prevailing torque is the only requirement I found in several Mil Specs I checked. I could find no use limit numbers...
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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!
__________________
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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07-30-2014, 09:18 PM
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Join Date: Sep 2007
Location: Central IL
Posts: 5,516
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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.
__________________
Bill
RV-7
Lord Kelvin:
“I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.”
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07-30-2014, 10:44 PM
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Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
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Quote:
Originally Posted by Toobuilder
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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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
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
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07-31-2014, 04:28 AM
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Join Date: Nov 2005
Location: Asheville, NC
Posts: 2,692
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Quote:
Originally Posted by BobTurner
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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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.
__________________
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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07-31-2014, 08:21 PM
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Join Date: Jan 2006
Location: PA
Posts: 264
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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.
__________________
Ken
Helicopter mechanic (A&P)
USAFR KC-10 Boom Operator, on final approach to retirement
My RV-9/8/7 dream may be on life support, but it ain't dead yet!
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07-31-2014, 08:31 PM
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fiber
I think they are confusing fiber lock nuts with metal nutplates.
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08-01-2014, 09:26 AM
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Join Date: Jul 2009
Location: Mojave
Posts: 4,652
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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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