I'm replacing the old school threaded steel fork and headset on a '70s Raleigh with a NOS steel Tange threaded fork and a Shimano 105 headset with sealed cartridge bearings. I chose the Shimano 105 primarily because it had the right stack height. I wandered down to the LBS to have the fork milled and the crown race mounted. They told me that since I was using a headset with cartridge bearings rather than loose bearings, that it was unnecessay to have the fork milled and crown faced. I just needed to have the crown race pressed on and I am ready to go. Being a skeptic by nature I thought I would get a second opinion from the doctors here. Are they correct?
Madone, De Rosa, Langster, some old Brit track iron
Any bearing needs to be mounted squarely, sealed or not. In theory they are not correct in their reasoning, but practically, I have found the Shimano cartridge headsets to be forgiving of misalignment. If the headset runs smoothly without sideplay, go ride.