I have some parts in an assembly (Flanges/pipe elbows, etc).  Is there a way to rotate them to a "snapped" position using 'free drag' or 'about entity'?

The problem I'm having, for example, trying to rotate something 90 deg.  It takes me forever to get it to rotate like I want using 'By delta x, y and z' even though I'm referencing the delta x, y, and z, coordinate icon (UCS), it still rotates the wrong direction (I'm sure it's doing exactly what I ask, and I'm simply inputing the wrong info).

Not sure if this makes since..