rcs7: below are the text of a pm from Mike Turner in answer to the same question I asked, and a link to a short thread mentioning stabilizing. Maybe it's more important for knife handles as they are thinner? I don't know. Evidently it's a good idea to seal the horn/antler to keep it from expanding and contracting. I'd like to hear from someone who has used it as you did (and as I intend) as a handle with a hole drilled in the end and epoxy (?) to adhere it?
Hi Gary,
Well here is a some up of stabilizing, this is from K & G's website who does the stabilizing.
STABILIZING
We do custom stabilizing. We are the original custom stabilizers for the knife making industry. We custom stabilize wood, stag, ivory, horn, bone, oosic etc. Why Stabilize? Stabilizing helps items become dimensionally stable and helps minimize or totally eliminate shrinking, cracking, expanding, warping and will not absorb water. Stabilizing items help them to become impervious to oils, raised grain when sanded and will take a very high polish.
Here is there website K & G
Now whether you need to depends on you. I just used a piece of elk antler on a knife that was supplied by the young man I helped build 2 knives he did not want to pay to have it stabilized. It was nothing but trouble it kept shrinking and expanding and warped.
Now using antler as a fire set handle material you may or may not have a problem, but keep in mind that it will shrink and do all kinds of things which may cause problems with the way you attach it.
Mike Turner http://www.iforgeiron.com/forum/f14/completed-knives-8035/