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.
Tofu is a great natural source of calcium. Chard is a good calcium souce, but it should be cooked to neutralize the oxalic acid it contains, which can affect calcium absorption. If someone is lactose intolerant, he may need to take a daily calcium supplement.Spinach can be used to make healthy, green smoothies.Some dairy products are fortified with vitamin D to boost calcium absorption. A sandwich made with Swiss cheese, a good source of calcium. Dairy products are a good source of calcium.Bananas contain calcium. A six-ounce serving of yogurt has 300 milligrams of calcium.Many nuts contain calcium. Milk is a good source of calcium. Spinach is one of the better-known vegetables with calcium. sandwich made with Swiss cheese, a good source of calcium. Dairy products are a good source of calcium. Bananas contain calcium. A six-ounce serving of yogurt has 300 milligrams of calcium. Many nuts contain calcium. Milk is a good source of calcium. Spinach is one of the better-known vegetables with calcium.