I will let you know how it goes. I had wanted to make a pulverin using some big junk horns I have. The recent post got me think again about making one. I figured I could make the spout from antler and thread it into the top. I now wish I had bought a larger diameter thread cutting kit but 1/2 inch might work. 5/8 might have been better for this if they make one that size.
After thinking about it if your wood threading box is like mine your threads are about 1/2-6 which is probably to course for antler and with out modification will not cut the threads far enough down so it will fit flush with the top. I would recommend standard taps and dies, 1/2-13 or 5/8-11.
If you start out with a piece of antler big enough to make a screw tip, let's say with 11-13 threads by the time you turn the antler down to 1/2" you will more than likely be in the pith, unless you start with a piece like this, which is solid for about the first 1 to 1 1/4".
Another thing to think about is the size of the hole that will go through the piece. Drilling a 1/4" hole first may weaken the horn, you will only have about 1/8th" around to thread, it dose not flex and may just break off once the threading starts. Because of the size needed you would probably be better off with a good solid piece of horn rather than antler. Unless you start with a I'm not big on saying something can't be done just that sometimes a lot of attempts need to be made before success is attained.
My suggestions, a good solid piece of antler, standard machine taps and dies or a two piece tip with the threaded portion made of a separate piece.
Tim C.
Also how are you going to hold it to shape it, the tip?