Hey. As an A&P for a commercial 121/135 air carrier, the FAA requires us to sign EVERYTHING off for return to service using a reference, even if it’s a small, seemingly insignificant common sense item like tightening a screw or changing a light bulb. It’s gotten, in many ways, outrageously ridiculous. No longer is a general reference to 43.13 acceptable, nor is a “description of work performed” good enough. Manufacturers manuals references make the feds the happiest and adjustments are made from there.
If there is any connection to any type of air carrier or commercial aviation, I can see why Grant is seeking a reference for his testing data. Even beyond that, these days the CYA factor helps a guy sleep at night and keeps the attorneys looking for something else to do where airplanes are not involved.
As far as the punch test goes, I’ve never been a fan. Maule tester maybe, obviously it is deemed OK on wing struts and seems to work in that context.
Beyond that, I’ve punched tubing with a most definitely UNcalibrated force (hammer) and punch and have seen tubing thick enough to resist the punch hits but for other reasons that tube was replaced anyway and revealed through the punch test, though it “passed”, it was clearly rotten or mostly so and was glad it was ultimately earmarked for replacement.
My small contribution, fwiw.
Cheers,Oz