Sometimes the 'mating' can be different from what it was when you initially took it apart because on some lenses there is an ability to set the focus at different points of the helical turn and match this new turn with the proper point on the focus ring.

Actually, you probably did not have to remove the helicoid; you maybe could have simply unscrewed the front and rear element sets. On some 28s that is so. But I usually do remove the helicoid because this gives me an opportunity to remove all the black gunk with lighter fluid and a brush, then re-lubricate with a tiny bit of Vaseline petroleum jelly. Most lenses have too darn much of this lubricant and ONLY NIkon was sparing in its application. That's why the focus on its lenses rarely stiffen with age. - David Lyga