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  #1  
Old 11-24-2016, 02:33 AM
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CubedRoot CubedRoot is offline
 
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Default HS-411PP bolt torque and washer on which side?

I am getting ready to finish up my rear spar, and I am at the point of bolting on the HS-411PP center bearing. I pulled the bolt, washer and nylock nut that the plans call for from my parts shelves, but I could not find for sure which side the washer is supposed to go on.

Does the washer go on the bolt-head side? or does it go on the nut side (between the nut and the HS-603PP spar).

Here is the details section of the plans, and it kinda looks like the washer is underneath the nut:


Secondly,
I am not sure what how much torque this bolt should get. The plans say to refer to section 5.20 of the book for the chart, which I did. It's below:



But I am not sure I am doing this correctly and wanted to get a confirmation from you all before I go past finger tight on these bolts.

This is an AN3 bolt, and an AN365 nut. However, its a nylon locking nut, but it has the designation AN365-1032. If I were to go by that chart, I should be torquing this thing down to 20 to 25 in/lbs right (looking at the first row, third column labeled "standard nuts")? The "self locking nut" section of that chart is for the MS210 nuts, which I think are the metal locking nuts.

Thanks!
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  #2  
Old 11-24-2016, 06:45 AM
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N941WR N941WR is online now
 
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Default

The washer goes on the side you turn. In most cases this is under the nut.

Don't forget to apply some torque seal once you torque it. In a couple of years, that will be the only way you will know if it is torqued or not.

Yes, 25 in-lbs is correct for an AN3 nut.

(I stamped the drill size and torque value on the cool bolt size plate that came with the kit.)
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  #3  
Old 11-24-2016, 09:46 AM
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sprucemoose sprucemoose is offline
 
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Default

Bill is correct.

Also- a lock nut requires a certain amount of torque just to overcome the resistance of the locking feature. This torque must be added to the torque value in the chart to achieve the proper torque. You can measure this resistance using a beam-type torque wrench.

If you are used to tightening nuts and bolts by feel, you'll be surprised how little 25 in-lbs really is. It is quite easy to over torque the small AN3 bolts if you are not careful. Some mechanics recommend only using the smaller 1/4" drive wrenches for this reason.
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  #4  
Old 11-24-2016, 12:45 PM
Aero_Octaveus Aero_Octaveus is offline
 
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Default Torque

For me, when I torque, I typically use the middle of the range. 22 or 23 in-lbs as every torque wrench has a bit of variance. This is my way making sure it's not too high, not too low. YMMV

When I started building...I found trying to figure out torque values a bit frustrating. Nothing is really clear, Especially when you are working with nylon lock nuts (As I thought they were self locking nuts....but they aren't)

Basically once you figure out the thread pitch and diameter for a given screw/bolt, and you know the designation of your nut...things start falling into place.

The real nail-biter for me lately is torquing bolts with nut plates as some nutplates have a fair amount of resistance to them.
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Last edited by Aero_Octaveus : 11-24-2016 at 12:55 PM.
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  #5  
Old 11-24-2016, 12:55 PM
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CubedRoot CubedRoot is offline
 
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Default

The chart is saying this AN365 is a "standard nut", but it has the nylon locking insert in the tail of the nut.

Do I need to measure how much torque the nylon applies and then add that to the torque specs? Or does the chart already take that in to account, given that it states AN365 as a standard nut?

I also looked at the specs of my Craftsman digi-click torque wrench, and it only goes down to 5 Ft/lbs, so I will need to pick up a decent 1/4" torque wrench. This is the one I have now: https://www.craftsman.com/products/c...ch-5-80-ft-lbs

It's been a great torque wrench, but looks like its a bit to much for these small bolts.
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  #6  
Old 11-24-2016, 01:00 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Default

Quote:
Originally Posted by CubedRoot View Post
This is an AN3 bolt, and an AN365 nut. However, its a nylon locking nut, but it has the designation AN365-1032. If I were to go by that chart, I should be torquing this thing down to 20 to 25 in/lbs right (looking at the first row, third column labeled "standard nuts")? The "self locking nut" section of that chart is for the MS210 nuts, which I think are the metal locking nuts.
There is a revision that will be published in the future that will change the "self locking" column to "metal self locking" (An AN365 nut is also self locking, just not all metal).

The page you got the chart from also discusses adding "prevailing" torque (as mentioned in other posts hear). The value listed in the chart is the value without the prevailing torque added.

The text from the page in Section 5 with the chart says -
When tightening fasteners with self-locking nuts the chart values must be modified. Due to the friction of the locking device
noticeable torque is required just to turn the nut onto the threads and does nothing to actually tighten the parts together and stretch
the bolt (clamp load). This is called friction drag (or prevailing) torque. The friction drag torque must be determined and then added
to the standard torque from the table. Run the nut down to where it nearly contacts the washer or bearing surface and check the
friction drag torque required to turn the nut. (At least one thread should protrude from the nut). Add the friction drag torque to the
standard torque. This sum is referred to as the final (or total) torque, which should register on the indicator or setting for a snap-over
type torque wrench


Common definition -
Prevailing torque is the amount of torque needed to run a nut down a thread on nuts that are designed to resist self-loosening under vibratory forces. These types of nuts are known as locknuts or prevailing torque nuts, as opposed to free-spinning nuts.

A nutplate should also be considered a self locking nut which requires compensation for prevailing torque.
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Last edited by rvbuilder2002 : 11-24-2016 at 01:03 PM.
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  #7  
Old 11-24-2016, 01:05 PM
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jcaplins jcaplins is offline
 
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Default Park Tools

I've found the Park tools beam torque wrench to be invaluable during my build.


search amazon for these: "Park Tool TW-1 Torque Wrench (1/4- Inch Drive, 0-60 inch Lbs)", or head to your local bike shop and see if they have them.
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  #8  
Old 11-24-2016, 01:09 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Quote:
Originally Posted by jcaplins View Post
I've found the Park tools beam torque wrench to be invaluable during my build.


search amazon for these: "Park Tool TW-1 Torque Wrench (1/4- Inch Drive, 0-60 inch Lbs)", or head to your local bike shop and see if they have them.
Very good choice..... just be sure to read the instructions carefully for any beam type torque wrench. Improper usage will result in an incorrect reading.
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  #9  
Old 11-24-2016, 01:20 PM
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CubedRoot CubedRoot is offline
 
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Thanks Jeff! Found it on Amazon for about $37 bucks, and it has tons of great reviews. Here is a link to it in case anyone else wants one:

http://amzn.to/2glPCTB

Looks like this will also let me measure how much torque it takes to turn the nylon lock nut on the threads, and then add that value to my desired torque.

Scott,
Are there any gotchas to using a beam torque wrench?
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  #10  
Old 11-24-2016, 01:34 PM
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RV7A Flyer RV7A Flyer is offline
 
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Default

Quote:
Originally Posted by CubedRoot View Post
This is an AN3 bolt, and an AN365 nut. However, its a nylon locking nut, but it has the designation AN365-1032. If I were to go by that chart, I should be torquing this thing down to 20 to 25 in/lbs right (looking at the first row, third column labeled "standard nuts")? The "self locking nut" section of that chart is for the MS210 nuts, which I think are the metal locking nuts.

Thanks!
Go here

www.gen-aircraft-hardware.com

and order the "blue book". It has the specs on every piece of AN (now MS) hardware you'll ever need.

AN365 nuts are, by definition/spec, nylon self-locking nuts. (New spec: MS21044).

21042, 21043 and 21044 are various kinds of all-metal locking nuts.

But get the book...you'll be glad you have it in your set of shop manuals.
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