it's not wood (but you can write with it)
Thanks to the George (Texatdurango) for posting his guide to making a fountain pen section in the library at the IAP website.
It took me two attempts to make one that allowed the nib feed housing to screw in correctly -- it seems I had a concentricity problem, drilling the holes from opposite ends allowed a tiny error which was just enough to prevent the feed housing from mating.
For the second one I adjusted the order of the steps -- drilling all the holes for the nib/feed unit from the same end and tapping the threads, then turning it around the cut the threads to mate with the barrel and drilling out to receive the cartridge converter.
Success! The barrel and cap were easy in comparison.
In retrospect, putting the cap screwthreads so far back from the end of the barrel wasn't a wise decision, as it forced the cap to be unnaturally long. (It posts, but is unwieldy.) On the positive side -- the pen is very comfortable and well balanced without the cap posted, and the Bock #5 nib writes smoothly (I loaded it with Noodler's Polar Blue.)