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.
For more info, see the section on calcium absorption. High calcium foods include dark leafy greens, cheese, low-fat milk and yogurt, bok choy, fortified tofu, okra, broccoli, green beans, almonds, and fish canned with their bones. The daily value (DV) for calcium is 1000mg.
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.