Is torquing bolts by feel really that bad? I had a guy argue with me about it yesterday.

I was working on a Cessna 172 cowling yesterday and this older mechanic kept telling me to just snug the bolts by feel instead of grabbing the torque wrench. He said he's been doing it for 25 years and never had one come loose. But I was taught you ALWAYS torque to spec, especially on anything flight critical. He laughed and said the spec is just a guide for new guys. Now I'm second guessing myself. Which side is actually right in the real world? Has anyone actually seen a bolt fail from not being torqued right on a small GA plane?

2 comments

2 Comments

terry_hayes1812h ago

That old mechanic is probably right for most stuff on a 172... people act like a cowling bolt is holding the wing on. I've seen guys torque a little 10-32 screw to 15 inch-pounds and still have it vibrate loose because the hole was wallowed out. The real issue is lock washers, proper thread engagement, and not stripping the nutplate. A bolt that's "torqued to spec" but has a caked-up lock washer or bad threads is worse than one that's just snugged correctly by feel. I'd rather have a guy who knows what a bolt feels like when it's tight versus a guy who blindly trusts a wrench on a dirty fastener.

robinl9011h ago

Respectfully, I see it a little different. A torque wrench is a tool for consistency not guesswork, and on critical fasteners like engine mounts or control cables you need that repeatable number no matter how good your feel is. The real answer is cleaning up the threads and using fresh hardware so both methods actually work as designed.