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.
Our diet gives us calcium. 1  The foods highest in calcium include: 2  dairy products such as eggs, milk, butter and cheese â this is where most of our calcium comes from. 3  green vegetables such as broccoli, spinach and beans. 4  nuts. 5  whole grain foods such as bread, rice and cereals.