I must disagree with the comments about the elk antler being too large. Nothing personal, guys. It is very possible the antler will turn down to the marrow, which is porous. When you reach that stage, stop turning and fill with CA, and continue. Repeat the filling as necessary. Some of the most stricking antler pens I made were from larger elk antlers. And, I must add that the only antler blow outs l've had werer from antler. You can see some elk antler pens in my yahoo photo album at
http://www.tinyuurl.com/38hor .
If you want the all white bone look that maybe resembles ivory, then large elk antler will not work. Go with axis deer antlere. But, the larger elk with its purplish (bloody) color makes for a wonderful pen. I have a customer who buys about 10 antler pens a year and he insists on elk antler. Just my thoughts on elk antler. I have good luck selling all types of antler pens. Antler close to the head contains more bone.
Note: Try mounting the antler pieces between centers and getting them round before drilling. Also, Cut a piece of the antler in half and see how it looks with bone on one side and the porous antler on the other.
Do a good turn daily!
Don