Different types of screwed joints place different demands on power tools. That's why it's important to make allowances for joint stiffness to achieve the proper torque in fastening applications.
"Fitting screws into steel without interlining components is one example of a hard joint with rapid tightening," torque-tool manufacturer Mountz Inc. explains in an educational article on its website. "For this application, the power tool needs to have a quick clutch that interrupts the torque at the preset level.
"Another example is a soft joint with gaskets and washers, or a long screw, [which] requires a screwdriver with a strong motor to attain short tightening times."
For joints with self-locking elements in the thread or clamped nuts, Mountz recommends a screwdriver with a shut-off clutch.
In the article, San Jose, Calif-based Mountz offers several examples to help manufacturers select the right power tool for the application. For more, read "Selecting the Power Tool to Suit the Joint."