It looks pretty good to me. You need a clip and a centerband on the cap would look good..I like a bit of metal, or a lot. If you chuck that nib section, you can use a parting tool and reduce the collar above the threads. This will allow the nib to screw in all the way. From what I gather what you are saying, the threads don't go all the way to the shoulder of the nib section, so you have to either extend the threads or reduce the material size in the unthreaded portion. Removing material is the fastest way. You can also remove the first couple threads inside the pen, it will do the same thing.