Pro tip: stop using your impact gun to tighten lug nuts

I had a moment about 2 years ago at a shop in Phoenix where a customer's wheel stud snapped clean off while I was torquing down a Toyota Camry. Turned out I had been zipping lug nuts on with my Milwaukee impact for years, thinking it was fine. The shop foreman walked over and showed me how the impact can over-torque them way past spec, especially on aluminum wheels. He handed me a torque wrench and said to use it for final tightening every time. I still use the impact to run them down, but now I finish by hand with a click-type torque wrench set to 80 ft-lbs. Has anyone else had a stud snap on them from impact over-tightening?

2 comments

2 Comments

robert_roberts14d ago

Hold on though, you said you've been using torque sticks, right? Do you actually test those things against a torque wrench once in a while? I've seen some guys at my shop buy cheap torque sticks from Harbor Freight and they were off by like 30 percent after a few months of use. The heat and banging around in the tool box can mess with them. So if your torque stick is saying 80 ft-lbs but really it's slamming on 110, you might just be getting lucky so far. I'm genuinely curious if you've ever thrown a torque wrench on after the stick just to see where it lands.

carr.brian14d ago

I've been zipping them on with an impact for like 15 years on all kinds of cars and I've never had a stud snap. I don't know, maybe I'm just lucky or maybe the torque sticks actually do something. Seems like one of those things where people get real religious about it but in the real world it's fine most of the time.