Backdrilling, or "match-drilling" 4

[Sparweb]

I'm so used to it that I take it for granted. It's the very common technique for laying out holes in one part and joining it to another one, NOT by laying out holes on it, but by alignment of the two parts, clamping, then drilling through the existing pilot holes from one into the other. This makes well-matched holes in both parts, eliminating misalignment as long as it's done correctly. I could say more about the process but I'm not here to teach it, I'm just getting across what I'm talking about so that my question lands in proper context.

Does anyone know of an industry standard for this process?
-or-
Does anyone know a reputable source that describes the procedure in a manner meant to teach it to personnel, designers, shop workers, inspectors, etc.?

I've checked with the usual suspects (AC 43.13, MIL-specs and MIL handbooks I frequently use, NAS618, etc.) It isn't described in the installation manual for Hi-Loks/HiTigue, despite being pretty important in the hole alignment for those transition-fit fasteners. I had also assumed it would be described in structural repair manuals for various aircraft, but no luck, there, either.
I'm going to get back my copy of Machinery's Handbook (on loan) tomorrow to see if I can find it in there.
For an industry so focused on defining a process for everything we do, I don't believe this should have slipped under the radar - it must be somewhere I haven't thought of looking, yet.

 

[Andy Weiss]

I'm so used to it that I take it for granted. It's the very common technique for laying out holes in one part and joining it to another one, NOT by laying out holes on it, but by alignment of the two parts, clamping, then drilling through the existing pilot holes from one into the other. This makes well-matched holes in both parts, eliminating misalignment as long as it's done correctly. I could say more about the process but I'm not here to teach it, I'm just getting across what I'm talking about so that my question lands in proper context.

Does anyone know of an industry standard for this process?
-or-
Does anyone know a reputable source that describes the procedure in a manner meant to teach it to personnel, designers, shop workers, inspectors, etc.?

I've checked with the usual suspects (AC 43.13, MIL-specs and MIL handbooks I frequently use, NAS618, etc.) It isn't described in the installation manual for Hi-Loks/HiTigue, despite being pretty important in the hole alignment for those transition-fit fasteners. I had also assumed it would be described in structural repair manuals for various aircraft, but no luck, there, either.
I'm going to get back my copy of Machinery's Handbook (on loan) tomorrow to see if I can find it in there.
For an industry so focused on defining a process for everything we do, I don't believe this should have slipped under the radar - it must be somewhere I haven't thought of looking, yet.

You know any A&P's? Ask them.

 

[Sparweb]

You know any A&P's? Ask them.

Yes, but none of them teach this stuff from a book or technical manual. They teach it in the shop: here's the tool, use it this way. That's how I was taught, too.

It's just us bookish engineers that go looking for some kind of written technical standard. For stuff everybody either knows or figures out for themselves...