Apr. 1, 2015. TDK Corporation has announced that its Hong Kong-based HDD head manufacturing wholly owned subsidiary, SAE Magnetics (H.K.) Ltd.
You use a wrench to screw, or unscrew a bolt. A screwdriver is for screws. Either way you turn it left. Some bolts have reverse threads and would turn the other way to unbolt.
Also, if you are replacing the drain, unscrew the nut holding the rubber gasket against the sink. Next, try to unscrew the drain flange from the T-connector. If this does not work (as it often does not) take a reciprocating saw (with a metal cutting blade) and cut the drain assembly in half just above the nut.