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High Quality Metric Fasteners

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Flow

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Hi folks, does anyone know where to get high quality metric fasteners, without buying Diamond or Airbus part numbers!
Something like these serrated M8 washers and M8 flange lock nuts.

image-11_1606685208037.pngimage-12_1606685207868.png
 

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Flow

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Thanks folks, I have been stunned at the pore quality and undersized specs on the thread of some metric fasteners. The nuts in the pictures above seem to be a flange and nylon lock. I ended up buying a $20 Airbus part just to secure the accelerometer for the dynamic balancer to the front oil seal housing because everything else I tried and measured was about 0.04mm under size in an M6 and felt funky in the threads...

Maybe something like this?
The cap screws look like 8.8 would they be a good match?

Any ideas where to get those serrated washers from. They don't look like half of a nord lock do they.
 

Mad MAC

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Hamilton New Zealand
For aviation places in NZ there is
Alpha Aviation will carry metric bolts but they are just DIN spec fasteners with their part numbers, can't guess as to the price.

Otherwise there is Sailplane Services in Dury.


Otherwise:
Unbrako might be a suitable brand (well it was 10 years ago but things change).

I have previously worked in oil & gas and all fasteners were required to be of USA or European manufacture (although only for European projects I think) maybe try one of the O&G associated supply shops in Taranaki (if they still exist).
 

Flow

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Nice one guys, will give Ross a call for sure, forgot that gliders are mostly metric.

This looks to be the conical Belleville friction washers.
1606856473024.png
This looks to be the nyloc flange nuts.
1606856461746.png

I have found them at EDL EDL Fasteners - EDL Fasteners but their Belleville washers are only 6x16mm rather than 8x18mm.
 

Flow

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I wonder if I can swap out the nyloc flange nuts with their 18mm flanges with these moly coated small flange items?
I can get these locally from Alpha Aviation, but not any Belleville washers with 18 or 19mm ODs to match the Nyloc flange nuts from EDL. Theirs are made in China as well. I can only 16mm OD Belleville washers here which will work with theses 8PH135Ms below...

1606865663571.png

It looks like DUC is using them in their hardware kits.
 

Twodeaddogs

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that'sthe profound problem with metric; for all it's supposed equality, essentially, it's as non-standard as Imperial. Airbus parts have a part number like a crazy phone number which does not relate to other metric bolts. The MS/AN/NAS system is wonderful by comparison.
 

Flow

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asn52320bh080n for example! Yes.
1606874534404.png

Found these locking spring disc washer type M.
1606874605548.png
 

David L. Downey

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I am afraid of the Bellville washers being used as standard washers...But that was all I was able to find with the both faces spiral serrations...
and...how do you determine the torque value for these? use the torque values for 5/16 US nuts and add the running torque?
 

BoKu

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I wonder if I can swap out the nyloc flange nuts with their 18mm flanges with these moly coated small flange items?
I can get these locally from Alpha Aviation, but not any Belleville washers with 18 or 19mm ODs to match the Nyloc flange nuts from EDL. Theirs are made in China as well. I can only 16mm OD Belleville washers here which will work with theses 8PH135Ms below...

View attachment 104812

It looks like DUC is using them in their hardware kits.
Just don't expect those thinwall nuts to develop the same clamping force as AN365s. They're great for shear and moderate tensile loads, but they fail in tension by expanding and leapfrogging over the bolt threads.

nut_test2b.jpg

[Off-topic] Edit add: This is from the "Breaking News" thread on VAF where Steve Smith and I tested a variety of hardware used on RV-8 landing gear leg saddles. We found that the NAS679A6 nuts supplied in the kit were marginal on tensile strength. Several RV-8 builders had reported that they had to tighten the nuts every annual or so because they had loosened. Our tests, and subsequent inspection of nuts and bolts in the field, showed that the nuts weren't unscrewing, they were being overstressed in tension and leapfrogging over the bolt threads. Replacing the NAS679A6 nuts with NAS1804-6 pretty much eliminates the problem.
 
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Flow

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There is also the issue that you are more limited to the number of time you can adjust a ground adjustable prop. Back to the Nylocs. Spoke to DUC last night and they said just Nylocs and plain washers is fine.
 

Flow

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Just don't expect those thinwall nuts to develop the same clamping force as AN365s. They're great for shear and moderate tensile loads, but they fail in tension by expanding and leapfrogging over the bolt threads.

View attachment 104840

[Off-topic] Edit add: This is from the "Breaking News" thread on VAF where Steve Smith and I tested a variety of hardware used on RV-8 landing gear leg saddles. We found that the NAS679A6 nuts supplied in the kit were marginal on tensile strength. Several RV-8 builders had reported that they had to tighten the nuts every annual or so because they had loosened. Our tests, and subsequent inspection of nuts and bolts in the field, showed that the nuts weren't unscrewing, they were being overstressed in tension and leapfrogging over the bolt threads. Replacing the NAS679A6 nuts with NAS1804-6 pretty much eliminates the problem.
Very useful info. It looks like the low profile rather than thin walled design is causing the overload.

I went ahead with the PH135Ms on the spacer to prop flange combined with the type M Wurth contact washers as these thin walled nuts are class 11 with higher proof loads than the class 8 (or 80 with stainless) and comply to much tighter tolerances than the commercial 6H tolerances.

Interesting to note that the A4-80 316 stainless nuts' threads are rolled so much better than anything non stainless in the commercial space. Even better than some class 10 nylocs I found locally. They are a much tighter fit on the bolt. So am using these stainless nylocs on the prop hub as it is ground adjustable. Being a carbon fibre hub I am using zinc plated washers between the nuts and the hub to keep the stainless and carbon separated.

I stopped short of using aviation hardware nylocs on the hub as they were $40 each and the stainless quality was plenty good enough.
 

Flow

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I have found a Diamond/Grob part LN9348-M8 for the nylocs.
Looks like the are class 11 as well.

Selbstsichernde Muttern dieser Norm mit Polyring und metrischem ISO-Gewinde nach LN 9163 sind für Verbindungen mit Schrauben einer Nennzugfestigkeit < 1 100 MPa anzuwenden. Diese Muttern sind nicht zur Verwendung in der Struktur vorgesehen. Anwendungsbereich −55 °C bis höchstens 120 °C.

1607032853530.png
 

Flow

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It looks the M8x15 washers are LN 9025-0815

1607074181899.png

After digging through the Pipestral and Tecnam IPCs I can see some of the M8 lock nuts are DIN 985 / ISO 10511. I have managed to track down some increased depth nylocs from Tecnam here but not sure on class as yet.

Does anyone know of a database with translations of these DIN numbers and their various TDS without having to pay 100 odd dollars to view the DIN specification?
 
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mullacharjak

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I have found a Diamond/Grob part LN9348-M8 for the nylocs.
Looks like the are class 11 as well.

Selbstsichernde Muttern dieser Norm mit Polyring und metrischem ISO-Gewinde nach LN 9163 sind für Verbindungen mit Schrauben einer Nennzugfestigkeit < 1 100 MPa anzuwenden. Diese Muttern sind nicht zur Verwendung in der Struktur vorgesehen. Anwendungsbereich −55 °C bis höchstens 120 °C.

View attachment 104886
Do the two dimples/marks on the corners signify the grade of the nut?
 
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