Metric bolt source

Well, I usually buy my aircraft hardware from ACS.

The first bolt picture is standard AN stuff, though you’ll have to translate those metric measurements into US for any ordering.
The 2nd sample is unknown to me (I’m sure someone here will know, ready to learn 😉), but an X usually denotes non-corrosion resistant steel.

Looks like standard AN bolts. Aircraft Spruce got tons

Dan wrote:

The 2nd sample is unknown to me

To me as well, but it’s still a standard AN bolt, K P is the manufacturer markings. (or could be some Chinese copy )

There’s nothing “aircraft grade” about them though, unless you include traceability paperwork (whatever that is worth). Structurally it’s like a metric 8.8 bolt that you find everywhere.

There’s nothing “aircraft grade” about them

…

Hex head aircraft bolts are made of high-strength type 4037 or 8740 alloy steel (type 8740 is most commonly used). The bolts are center-less ground and threaded after heat treatment. Minimum tensile strength 125,000 PSI. Cadmium plated per specification QQ-P-416A, Type II, Class 3

The American & British aviation hardware systems are well documented and supply quality products with traceability, Metric is another game entirely.

Metric hardware is simply industrial standard hardware that the aircraft manufacturer has decided is good enough for the application. This gives the aircraft manufacturer the opportunity to but something from a reputable industrial supplier and then add a considerable margin to sell it with a form 1.

It is interesting that Airbus has never used any metric hardware because for them it is far more important to have a reliable source of hardware that is available worldwide and they have bigger fish to fry than buying a few bolts from RS and jacking up the price with a form one.

It my view the European manufacturers who use metric hardware have been shortsighted as the hardware issue is an impediment to penetration of the worlds biggest aircraft market.

Are there many European aircraft manufacturers who stand a chance of selling to the USA?
And would the sales be big enough to cast aside the metric system which is used in Europe for just about all measurements?
The market is big but also contains the majority of manufacturers of ga aircraft and engines.(Not totally sure about the engines these days.)
Tecnam for instance are a big fish in the small pond (Europe) would they not be tiny in the big fish pond (USA).

@Snoopy
I forgot, but ACS has a European branch, though the stuff is more expensive there, quite some savings on shipping from ACS.eu.
The other good thing about the European store is the possibility for free pick-up at EDTG Bremgarten (how’s that for a mission ), and same part numbers as ACS US.

PS
I usually buy my engine oil from them, and shipping DHL to my German address is affordable.

An ‘x’ is frequently used for AN bolts in lieu of the 6-point asterisk

Dan wrote:

Hex head aircraft bolts are made of high-strength type 4037 or 8740 alloy steel (type 8740 is most commonly used). The bolts are center-less ground and threaded after heat treatment. Minimum tensile strength 125,000 PSI. Cadmium plated per specification QQ-P-416A, Type II, Class 3

A metric 8.8 bolt is stronger grade steel and better tolerances. Better all over actually, except the practicalities of using them in an aircraft.

My point was that without traceability paperwork, they are NOT “aircraft grade”, they are just bolts. At Aircraft Spruce you can hook off traceability for an extra fee.