Go to a hardware store and get the size bit you need that is made for metal. Most cast iron isn't really hard unless it is white cast iron. If the hole is over 3/16, pre-drill it with a small bit first. It might be a good idea to use some cutting oil to.
Other foods that are high in calcium include: 1  Spinach. 2  Kale. 3  Okra. Collards. 4  Soybeans. White beans.  Some fish, like sardines, salmon, perch, and rainbow 1  trout. Foods that are calcium-fortified, such as some orange juice, oatmeal, and breakfast  cereal.
Goat's milk and cow's milk both are rich in calcium. Two other good sources of calcium are mozzarella cheese and blackstrap molasses. Other good sources of calcium are oats, wheat durum, pistachios, hazelnuts, Brazil nuts, cheddar cheese, cheese cream, eggs, caviar, pollock, low fat cream, pollock, and perch.alcium Rich Fruits and Vegetables. Everybody knows that milk and milk products are a good source of calcium. But, there are also many calcium rich fruits and vegetables which make an excellent source of this mineral.