mechBgon, big thanks for the picture. I can see what the problem is now, here's a pic of the parts I have for comparison:
Part on left is the NoThreadset top cap, see how shallow the boss is. Part on right is the Gripnut, the boss matches the two 1 1/8" parts in your picture. You can see how big the 'air gap' is, possibly the first time I've used an orange for a technical purpose :O) But seems I have two options now, a) new forks and use the NoThreadset, or b) new Chris King Headset
