Jerry,
Antler stinks. As in smells very poorly!!!
Turn like a hard plastic, very sharp tools. If you have a dust collector, the smell can go "away from you" and life is better.
Cutting the antler can be a challenge - whitetail deer did not cooperate when they decided to have the rack "curvy" instead of straight. Look for areas that are about 3/4 to 1 inch in diameter and relatively straight - measure with the tubes you are going to use, see where it will fit. Cut on bandsaw, if you have one.
Remember that antler "bark" (the outside part) is desirable in the finished pen, so if you can incorporate it while turning, do so.
I'm sure you'll get lots more info from those who have turned more of it than I have, but this is a start.[
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