The Flying Bolt.

So the airframe mechanic rings through to fastening parts to get a set of window bolts.
"We don't have any AR17767 bolts" says the fastener specialist.
"What about AQ77567s" Says the mechanic.
"We got 'em, but you can't use 'em"
"Why not?"
"They're the wrong bolt, different part number."
"Don't give me shit about part numbers. They are the same length, same pitch, same socket"
"Mate, you can't use them. They are the wrong bolt. I know fasteners and you shouldn't use these on that aircraft."
"How many effing planes have you worked on eh?. I have been an airframe mechanic for 27 years. Don't tell me about bolting a window into a plane, just give the the effing bolts."

So the bolts fail at 35,000 feet and the pilot is half out of the window.
What went wrong?
The airframe mechanic only thought about putting the window in the hole. The bolt guy only thought about the bolt. The properties of a tensile fastening bolt are agnostic about what is being held together. It comes down to tensile strength, temperature characteristics, hardness etc.
It does not matter what the bolt is being used to hold together, that is totally irrelevant.
The window can only go into that aircraft. Not into a caravan or glass house. The bolt on the other hand can be used for any application that does net exceed the specs for the bolt.

The airframe mechanic came to the fastener specialist with a solution, not a problem.
The problem was finding a bolt to secure the window. Not securing the window per se.

He should have said "I have a problem and need to do xyz", can you give me a solution. Not, "I have a problem and need to do xyz and I want you to do abc"

He got what he asked for, but not what he wanted.

Don't go to specialists with a solution, give them the problem.