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.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.
![]()
DUC FLASH PROPELLER HARDWARE KIT | Aircraft Spruce
DUC FLASH PROPELLER HARDWARE KIT Select the best fit for your Duc Flash Prop, from 130mm to 200mmwww.aircraftspruce.com
Very useful info. It looks like the low profile rather than thin walled design is causing the overload.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.
Do the two dimples/marks on the corners signify the grade of the nut?I have found a Diamond/Grob part LN9348-M8 for the nylocs.
Looks like the are class 11 as well.
DIN LN 9348 - Aerospace - Hexagon nuts, self-locking, with reduced width across flats, for temperatures from -55 °C to +120 °C | Engineering360
Find the most up-to-date version of DIN LN 9348 at Engineering360.standards.globalspec.com
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