The number of silver coins required make 1 oz of silver is determined by the size of the coins in question, and the composition of the metal used to manufacture them. For example, it takes 14 dimes issued between 1875 and 1964 to make 1 oz of silver.
Dimes issued between 1875 and 1964 weigh 2.50 grams and are comprised 90 percent of silver and 10 percent of copper. The peace dollar manufactured between 1921 and 1935 is made 90 percent, or .7735 oz, of silver. It would require two of these peace dollars to equal over one ounce of silver. The majority of silver coins are not made 100 percent of silver, so estimations will vary from coin to coin.