used to be a thing "everybody did" but maybe they all did it badly...in any case you hardly ever find any shop who will lathe-cut (or die-cut) more threading on a garden-variety steel steerer.Some folks who used to cut threads will now only cut off the old and splice on a section of new steerer, which CAN be a plus (sometimes) if you want a much longer steerer than you have or swap from threaded to threadless (vice-versa). But if you just want what you want, and that's a few threads cut...go fish!