Dario,
Antler is hard and takes sharp tools. It is not difficult to turn, just take light cuts at first and you will learn how much you can take off. Each piece is a little different.
Soak CA (thin) into the porous bone marrow part when it starts to appear. I do not use a CA slurry with sanding dust like we do with some woods. Don't like that look, but you may give it a try. You may like it.
Sand as usual and finish with MM. I usually buff with white diamond, apply my CA finish and MM again and buff.
For slightly curved pieces I mount between centers. Turn on the lathe and you can see by the "shadows" if you will have enough to make a pen. Moving the centes will show more or less pen. Find the optimum amount of antler "cylinder", then rough the antler round. Now it is drillable. Since rounding this way first, I have not miss-drilled any blanks. Trying to drill withoug rounding was very frustrating to me. I drill out the side on the exit end LOTS.
If you want some really nice enamel or bond, get hold of some axis antler. The bone marrow vein is tiny and is often drilled out. Each piece of antler will be a little different and I have not figured out a way to know what is inside.
A nice touch is to drill off center and leave a little of the "bark" of the antler's surface showing. It is a very nice touch.
Good luck with the antler.
Do a good turn daily!
Don
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