I used to think torque wrenches were overkill for panel screws

Been turning wrenches on GA stuff for about 8 years now and I always figured my arm was good enough for the little stuff. Then last month we had a Cessna 172 come in with a cracked glare shield panel near the fastener holes. The old A&P I work with showed me how overtorquing had stressed the plastic over time, a tiny bit each time. He busted out the inch-pound wrench and we did the whole panel at 12 in-lbs, and it sat perfectly flat with zero stress marks. Now I use the torque driver on every interior panel and trim screw, no exceptions. Anyone else notice how much better panels fit when you actually follow the numbers?

3 comments

3 Comments

finley_flores286d ago

Had a Piper overhead panel do the same thing last summer. Took the screws out, let it sit for three days, and it flattened right out. Put it back at 16 in-lbs and it has been perfect since. Pretty sure that panel was a few clicks away from cracking altogether. Torque wrenches are cheap compared to replacing interior parts.

wadea5317d ago

Tiny bit each time" is exactly right. I think the other angle here is that modern interior plastics are way thinner than the old stuff from the 80s. I had a Piper Archer where the overhead panel was almost warped from years of gorilla tightening. Once we torqued it to spec and let it sit for a week, the panel actually relaxed back almost flat. Makes you wonder how many panels got replaced or bondo'd up over the years that were just wrecked by an overzealous screwdriver. Ever had any luck with a warped panel settling back down after you backed the tension off?

faithg2617d ago

That 172 glare shield story hits hard, I've seen the exact same stress cracking on the same plane.