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.
  Another one of the most beneficial 3 food sources of calcium is fish. Sardines, tuna and salmon are considered to be rich in calcium and provide many health benefits. 1-2 cups or 5-6 ounces of these fish, with or without bones, are enough to provide up to 300 mg of calcium.You can also buy canned salmon and enjoy a healthy meal full of nutrients.   The last of our 3 food sources of calcium is calcium fortified orange juice.-2 cups or 5-6 ounces of these fish, with or without bones, are enough to provide up to 300 mg of calcium. You can also buy canned salmon and enjoy a healthy meal full of nutrients.   The last of our 3 food sources of calcium is calcium fortified orange juice.