The Normal To 2 Faces command gives the user greater control over the orientation of their model.
Select 2 faces using "Ctrl", then click normal to (or N on the keyboard).
Your 1st selection will be displayed
normal to you & your 2nd selection will be displayed normal to the vertical.
This tool is extremely useful if your assembly has been imported in a strange orientation or when you are struggling to find a certain view out of the standard tools in a drawing.
By Jon Weston-Stanley