I am rebuilding a bike and have the LBS installed the a new top/bottom headset race and also the fork crown. I keep the original lock nut and the adjustable race because of their special threading tpi (an old English Raleigh).

The problem is when I turn the handlebar I can feel it gets stuck/not smooth at one spot. I know this isn't due to overtightening on the adjustable race because the fork can still be wiggle a bit after I tighten the lock nut (kinda too loose actually). I have brand new ball bearings in there so it can't be them. Nothing is touching or pushing against the bottom race when turning. Also checked the steer tube and it seems straight to me. I have no clue and can't figure it out what's the issue here. Please help!