My minority position opinion regarding the use of power tools for attaching machine screws, when threading into a tapped hole, is a practice to be avoided as you loose the control over detecting when you may begin to cross thread a tapped hole (as first clearing the paint in the tapped hole by hand is usually a skipped step).
I use power tools for drilling holes. I use hand tools, properly sized, for installing screws. This takes longer, but the end result is worth the increase in final "fit and finish". SDI has their Installation Troubleshooting Guide for Standard Steel Doors and Frames as seen here:
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