Try using bone points. I have made barbed points from the leg bone from cows that the dogs drug back to the house. DO NOT USE A BONE WITH THE MARROW STILL IN IT !!! When you cut that sucker open, the smell will gag a maggot! Use one that has dried out. Also, I cut the ends off and then saw it lengthwise with a hack saw. I then put it in a big pot and boil it for 20 minutes or so. That way, when I am grinding on it and I inhale some dust, it doesn't have live critters on it. I use hand tools, work outside, watch the wind, wear a dust mask and still end up with bone dust in my nose. Bill