Yes, but it's not an easy job. There's a fair bit of metal to be removed, and that's hard work with a tapping die. Fork threads are normally cut on a lathe, but once the fork is built that's not really an option. Also, it's critical that the die is straight when it starts to cut the thread, otherwise the thread will go off-centre and weaken one side of the fork. It's not a job I'd want to do myself, but you may find someone out there who has the tools, skill and brute force to be able to do it.
Surely easier to melt out the steerer and braze in a new one, then repaint the fork, than it would be to lathe turn threads on the steerer with it still attached to the crown.
Yes, but it's not an easy job. There's a fair bit of metal to be removed, and that's hard work with a tapping die. Fork threads are normally cut on a lathe, but once the fork is built that's not really an option. Also, it's critical that the die is straight when it starts to cut the thread, otherwise the thread will go off-centre and weaken one side of the fork. It's not a job I'd want to do myself, but you may find someone out there who has the tools, skill and brute force to be able to do it.