There was a thread about this many years ago... IIRC some sort of hydraulic press is used.Jerk_Chicken said:
Marzocchi USA does it for about $75 last I checked... once in a crown's lifetime.
oh yeah, new steerer's run about $35 from 'zoke USA (for aluminum), though RST steel one's fit the pinch bolt crown's and are much cheaper. Jenson had 'em for about $20 a while back.