It is possible but now without caveats, apparently. There's some discussion on it here, starting at the bottom of the page. A good shop might do it, if the steerer is solid enough...
Edit: the threading would be done on the outside so the internal diameter would not change. Potential problems are the steerer becoming thin and weakened at the threading. And of course eternal regret, as there is no way back. Nitto stuff is nice but that one quill stem that is just right can be hard to find. With a-head stuff I only ever hear people complaining about looks...
Edit2: just looked up affinity's web page. Can't you just order a threaded fork from them? Might not even be that much more expensive than having the threading done, right?
It is possible but now without caveats, apparently. There's some discussion on it here, starting at the bottom of the page. A good shop might do it, if the steerer is solid enough...
Edit: the threading would be done on the outside so the internal diameter would not change. Potential problems are the steerer becoming thin and weakened at the threading. And of course eternal regret, as there is no way back. Nitto stuff is nice but that one quill stem that is just right can be hard to find. With a-head stuff I only ever hear people complaining about looks...
Edit2: just looked up affinity's web page. Can't you just order a threaded fork from them? Might not even be that much more expensive than having the threading done, right?