Just about anyone other than a mouth-breathing moron who needs help tying his own shoelaces can be trained to snug lug nuts with an impact wrench without exceeding the torque specs. That's why every professional-quality air wrench has a built-in pressure adjustment valve. Even with an impact set near its maximum power, using the correct "torque stick" for a specific diameter and pitch of lug stud will prevent over-torquing, as long as the proper technique is used. Shops that routinely overtorque lug nuts need a change in management, not necessarily a new work crew. Of course, someone who has not spent a lifetime in the auto repair business might not be aware of the tools and techniques available to professionals at the trade. That's what that "ASE Certified Master Technician" shoulder patch that a lot of us wear is all about. An automotive Master Technician is certified in 8 categories, and he must recertify every 4 years. Keeping 22 certifications current is a bit more of a challenge.
Jerry
