Adjust Threaded Headset
Refer to Headset Parts for a photo of individual headset components.
Tools needed to adjust a threaded headset are:
preferably a secure work stand
headset wrenches--there are a number of sizes, with 34 mm and 36 mm most common
The procedure to adjust a threaded headset is:
1. Preferably, secure the bike in a work stand.
2. Loosen the locknut--the uppermost nut on the steering tube--by rotating it counterclockwise. It is not necessary to loosen the stem. You can use a large adjustable wrench if you don't have a headset wrench that fits it.
3. With a thin headset wrench, loosen or tighten the top bearing cone, aka adjustable cup. Clockwise tightens. Counterclockwise loosens. Find the adjustment that allows the fork to rotate freely without catching, but that holds the fork steering tube securely in the bike's head tube with absolutely no play.
4. While holding the top bearing cone, securely with the headset wrench, tighten the locknut down--very tightly--onto the adjustable cup.
5. Test the headset adjustment. Don't be dismayed if it is out of adjustment. It is hard to snug the locknut down without moving the adjustable cup. Keep trying until you get it right. Don't quit--it will work.