take a picture and post this anomoly
bike frames are usually one of the following headtube sizes:
1 1/8"
1 1/4" (rare)
1"
these can be either threaded or threadless (I think 1 1/4 was all threadless?), depending on the combination of headset and steertube.
If you have a 1" steertube, you can get a 1" threadless headset and a 1" threadless fork to accomodate your needs here