Started taking apart and removing my old front fork tonight, and wanted to mock up the new one so I could cut it and go get the star nut installed at the LBS this weekend. I'm having trouble getting some of the pieces of my headset to fit over the steerer tube. They are 1 1/8" threadless, and my micrometer says both steerer tubes' diameters are within .01mm of each other.

For starters I can't get this piece that goes between the fork and head tube to seat all the way down. Does it require it to be pressed on with some kind of special tool? I did have to tap it off of the old fork with a hammer and screwdriver:



Also I can't seem to get the top ring of the headset to slip down over the tube.



I did manage to get the o-ring past the top edge of the tube and get the top edge of the ring flush with the top of the tube. But I can't seem to get it to go any farther, at least not with my bare hands. Any tips or tricks?