I made this pen earlier this year and it threaded nicely and worked well up until I put it into a box and mailed it to it's new owner.
I haven't heard any negative comments from the new owner, I'll try contacting him and getting his opinion on how the threads are holding up. Hopefully they are holding up well.
I also made the bloody red jasper and although it has plastic threads on the section, the cap is threaded to match and I have this pen in my desktop rotation and have not noticed any thread degradation yet. It is used probably a few times a week.