Peter – not quite right as in they are 6pt hex, but hi-temp and self locking Link
Taking a different tack, I would speculate that the loads are trivial – otherwise you would simply destroy the clamp. Surely on N-reg you can approve pretty much any credible nut and bolt combination? Does AC43-13B have anything to say?
The relevant text is in AC 20.62E : Eligibility, Quality, and Identification of Aeronautical Replacement Parts
f. Standard Part. Is a part manufactured in complete compliance with an established
U.S. Government or industry-accepted specification, which includes design, manufacturing, and
uniform identification requirements. The specification must include all information necessary to
produce and conform to the part. The specification must be published so that any party may
manufacture the part. Examples include, but are not limited to, National Aerospace Standard
(NAS), Air Force/Navy (AN) Aeronautical Standard, Society of Automotive Engineers (SAE),
Aerospace Standard (AS), Military Standard (MS), etc.
a. Replacement of Parts and Materials. The performance rules for replacement of parts
and materials used in the maintenance, preventive maintenance, and alteration of aircraft that
have (or have had) a U.S. airworthiness certificate, and components thereof, are specified in
§ 43.13 and part 145, § 145.201. These rules require that the installer of a part use methods,
techniques, and practices acceptable to the FAA. Additionally, the installer of a part must
accomplish the work in such a manner and use materials of such quality that the product or
appliance worked on will be at least equal to its original or properly altered condition with
respect to the qualities affecting airworthiness.
Yes the loads must be trivial.
Looking back at the photos I posted, they date from 2002 when the engine came out for a shock load inspection (with just 1hr on the aircraft, a prop strike due to a pothole!) and I took loads of pics to make sure the maintenance co put everything back the same way.
And they show a locknut, 12 corners, like this
I’m sure as long as you use “aircraft quality parts” with equal dimensions you will be fine. I can’t imagine that being a problem on an EASA reg either. It’s not like the bolt holds together the wings or anything. But then, I’m an experimental dude …
One issue with using ANSI (US) bolts is that 10-32 is too small and 1/4" is too big
One curious thing is that the FAA owner produced parts concession (for discussion purposes, I am proposing machining up the bolt out of stainless steel) prohibits doing that with standard parts (AN, MS etc), but these are not standard parts, are they?
I also found this interesting table here
It does make one wonder why one should replace these crappy steel bolts (which after a few hundred hours are so corroded they break when you try to undo them) with more crappy steel bolts!
Peter, just to make sure it’s M6, can you measure the thread pitch? The easiest way is to press the bolt against a sheet of paper, then measure the length of 10 or so consecutive threads imprinted on paper. Normal thread is M6x1, fine is M6x0.75 (which is unlikely at this location).
but these are not standard parts, are they?
Of course they are – they’re standard Metric parts and the standard is ISO .
or high tensile galvanised for the nervous
Don´t forget to apply copper grease when mounting stainless as an antiseize.
Anyway, get a handful of any type and change them each season, no worries about corrosion.
u will find the nuts here
http://www.paoloastori.com/en/
http://www.paoloastori.com/images/pdf/dhn.pdf
DP40 type
and dont use copper grease if it gets very hot use this
BOSTIK NEVER SEEZ PURE NICKEL Special
http://www.neverseezproducts.com/purenickel.htm
good source for bolts
http://arp-bolts.com/kits/ARPkit-detail-b.php?RecordID=2987
