Hello, I was wondering about what would make a better face gluing surface,
running a board through a planer or through a drum sander?
I have seen many suggest using a planer first and then finish the
board with a 120-180 grit drum sander for face glue-ups. My questions are:
Wouldn't a 180 grit sanding be too coarse for gluing and why sand an
already planted surface, which is supposed to be as smooth as one can go?

Would appreciate any feedback and comment!
Thank you and Best wishes,
YS