I for one would be really worried about lost trichomes on the blades and sides of the coffee grinder, so I wouldn't bother with it. Also, with a coffee grinder, you're going to be grinding your bud too fine.. it's going to make for a shitty smoke, i.e. burning too fast, excess inhalation, etc.

I'm with opiuser: either I just toss in a nug, or I don't break the nug into more than about three or four pieces. Even if I'm rolling, I break it up by hand, and I break it up just small enough that the size of the pieces doesn't affect the shape and quality of the joint/blunt.

Peace