I recently had a old racing frame powder coated and before hand i got a friend to take off the forks for me. when i got the frame back i realised that they had coated the steering tube as well which meant the little metal ring would not fit into place. I have sanded down the steering tube and attempted to put the forks back exactly how they came off however the top bearing cup does not seem to go tighten enough for the locknut's thread to be engaged. can anyone hlpe me with this problem any infomation about headsets would be great as well thank you

By "little metal ring", I presume you mean the crown race. Be sure it is installed down all the way and firmly against it's seat. If you left it too high, that would effectively shorten the steerer and could be the cause of your problem.

If you aren't conversant enough with headset installation, I recommend you visit a bike shop with the proper tools.

i have the crown race as far down as it will go so thats not it any other ideas?
thanks anyway

Did you install a different headset? If so the stack height may be more than the original and that would explain the problem too.

Also check that the headset cups are fully seated into the frame. Look for any gap between the cups and the end of the headtube. Unless you changed the headset to a taller one, the thickness of the paint cannot account for enough change in height to cause your problem.

Is it possible that you installed the ball retainers upside down? That could cost you a few millimeters, besides not working right when you finish.

If you've mistaken the way the bearing cages are supposed to go in so they are upside down then that can increase the stack height and prevent you having the room to get the top nut on.

It also helps if we are all talking about the same part. There's a lot of "little metal rings"in a headset. Go to https://www.parktool.com/repair/readhowto.asp?id=127 for a description of removing and installing and adjusting threaded headsets and the correct name of the metal ring that is giving you trouble. This is just one self help item that you can find at www.parktool.com/repair . For other things hover your mouse over the part you need help with and click. That's where the info on headsets came from.

Oh, and often the upper and lower race press in collars are not the same length or the actual cups are of different depth. If you tried to push them in to the wrong position this may be why it isn't fitting the head tube correctly. The cups may not be fully seated in one case or the other parts you're fitting into them may not be seating correctly due to the cups being reversed in the head tube.

BCRider, I am pretty sure that i have the bearing cups in the correct place as before i put them back on i tried different variations with bearings in them and only one order to worked properly. Just how far down does the locknut need to be?
Thanks
Charlie

you need to go look at the websites described to be sure you have the parts in the correct sequence/position.....

The locknut on a threaded steerer only needs to be on about three complete turns. Ideally, the top of the steerer should be just below the top of the locknut by 1 mm or so when the locknut is fully seated and tightened.

Thank you everyone for your suggestions. my best bet would probable get some professional help

Did you also sand the powder coat off the edges of the head tube before installing the bearing cups? Between those two spots if the coating is a bit thick that could be all it would take to ruin things. Same with the powder coating thickness down at the base of the steer tube where it meets the crown. All three of these spots would need to be trimmed of powder or at least the coating would need to be thinned well enough that it is no thicker than regular paint on those spots.