Crank it down until it strips out, then back it off a quarter turn :)

Other than the James Sweet reply, I can throw in that most drain plugs seem
to torque to about 33 ft-lbs. Even on Hondas, which are notorious for
stripped pan threads, 33 is the spec.

Mike

remember torque of a bolt (or nut) is determined by the stress in the
bolt AND the frictional resistance of the sliding parts.  A clean dry
bolt and nut or housing will need to be torqued much more than a oily
one.  This is one area where a torque wrench can do a disservice.  I
once visited a auto manufacturer who was shearing off bolts on a
suspension component.  They were trying to meet the torque spec but the
bolts would shear before the torque was reached.  They blamed ppor
quality bolts...Turns out the spec called for unlubricated components
whereas they were applying a release agent before assembly.  On the
other hand dry steel on dry aluminum has very high friction so a torque
wrench may reach torque before the bolt is even truly tight.

Before you rely on  a torque wrench  see if the spec mentions bolt
cleanliess and always use common sense...with practice you can feel how
much friction is present and make allowances for that in setting the
torque (with or without a torque wrench).