These were the days when the British had their own screws (from a continental European perspective). People buying a Landrover on the continent also needed to buy a set of suitable wrenches.
I guess the same holds for America. Not sure whether American screws would be the same as British ones or whether they would differ like the volume of a gallon.
With global manufacturing these days, Japanese cars everywhere, German cars in America, how many screw standards are still in use? When did it change, if it did?
That may be true but it's not relevant to this accident. It was a British made plane using British standard screws. The mechanic just used the wrong size bolt from the same standard. It's not like he was trying to find a metric equivalent to an imperial size or vice versa.
According to the wiki, one of the recommendations from investigating body was that aircraft maintenance crews wear corrective lenses. Reading between the lines, it suggests that the tech didn’t either see the proper screw size or didn’t want to cross-reference with documentation because they couldn’t see the text.
If you want to delve into that particular rathole, I recommend Carroll Smith's Nuts, Bolts, Fasteners and Plumbing Handbook. More than you ever need to know about the subject.
My memory is fuzzy (used to do sheet metal repair for L3 and Boeing), but I'm pretty sure the FAA requires nearly everything to be "American". This means pilots must speak English and all aircraft hardware is of the AN (army-navy) or NAS (National Aerospace Standard) standard.
Hardware is always in English units (inches). In this case, the #8 screw (5/32") was used in place of a #10 (3/16") screw. Side by side, the size difference is obvious. Trying to judge the screw size by looking at the hole is not so obvious and a #8 screw will sort of cross-thread into a #10 hole because aircraft female threads are "interference fit" by (at least) about .001" so screws and bolts won't vibrate loose. I've made the mistake before but if you are paying attention, you'll know you got the wrong screw just by how sloppy it goes into the hole. That and #8 screws are only used on mostly non-critical stuff. If you were to take every screw,rivet, and bolt on a plane, 90% would probably be 3/16" in diameter.
My brother in law works in aerospace, he worked on a project which involved a mars mission - the catastrophic error was that part of the software worked in metric and part of it worked in imperial measures. Each independantly worked in factory testing, but together the imperial readings threw the metric system (it was just a number) - or vice versa - no one caught the error
There is still plenty of scope for tears. I had a Shimano internal hub gearing system on a bike. It had a bolt and nut with a thread that was unusually tight. More threads per mm.
It was very easy to strip and I did it numerous times. Every second time I ordered new ones the wrong ones came and I’d strip them too.
Internal hub gearing is amazing, but comes with intense pain.
The metric standard distinguishes 3 thread pitches: regular, fine, and superfine. So even if you say it's the same standard, not everything of the same size matches.
I also have Shimano internal hub. It's claimed spare parts are impossible to get. Of course just a screw might be different. When it broke it was replaced as a whole, luckily on warranty.
Airplanes operated for passenger transport are on a very controlled maintenance program. Almost all parts are numbered and tracked, including their age, flight hours and cycles (basically number of flights). You cannot replace even a bolt with another that isn't according to the same manufacturer spec and tracked in the same manner.
So some screws could be the same spec, but in general you don't just pick one out of a bucket and screw it in.
Even non-US aircraft use a lot of imperial fasteners (and pipes). This is mainly due to inertia. Since both maintenance shops and suppliers are already equipped.
I guess the same holds for America. Not sure whether American screws would be the same as British ones or whether they would differ like the volume of a gallon.
With global manufacturing these days, Japanese cars everywhere, German cars in America, how many screw standards are still in use? When did it change, if it did?