Joe - When any antler has pith there is absolutley NO need to remove it or use modern methods to stabilize it.-
1) drill a hole in the middle slightly smaller than the tang
2) then boil it until the pith is "soft"
3) While it's still hot jam the tang down into the hole - heating the tang helps - I lock the blade in my vise tang up, heat with a torch and when teh antler is ready jam it on and pund it down tight with a rawhide mallet....
the pith turns to a nice solid glue when cool - it's one method our ancestors from way back when (aka the stone age) used before epoxy was invented and it has held up well on /most originals made this way.....I also use cross pins, but then I wear a belt and suspenders....
Some (often) times the old ways work as good or even better than the modern ones...i.e epoxies generally have a lifetime of less than 50 years and most much shorter, on the other hand many old methods such as described or cutler's resin have held up quite well for millenia.......