Very nice Tim ! Where do you guys get the odd pices to make the threaded collar and screw in tip. Are they always made out of horn or antler? I like to try to make one of these style of horns but not sure where to get the odd pieces to "play" with. I have imitation ivory (ivory macarta) and such that is used for knife handles can that be used?
I buy just the solid tips if I can ( looking for a good source now) Sometimes they are large enough to get a tip and a collar out of but most of the time it takes two tips, which may get two sets from, a collar and the screw tip. I have quite a few raw horns so at times I will just cut the pieces off a whole horn, the straighter the better. On Philly style horns you will probably not find horn and antler mixed, more likely both pieces will be horn. I would also stick with natural materials.
The collar is not threaded on this style of horn, in some other styles they are, the collar in this case serves to strengthen the threaded area.
This may help you see it better:
http://americanlongrifles.org/forum/index.php?topic=13901.msg130825#msg130825 Tim C.