Grind pork into a large mixing bowl using coarse blade of meat grinder. Add ground beef, 1/2 cup water, salt, pepper, sage, garlic salt, and garlic; mix well.
Rinse pork casings thoroughly with warm water; drain. Tie one end of each casing securely with cotton string. Stuff sausage mixture into casings according to basic directions for stuffing sausage. Twist and tie casings into 8-inch links. Refrigerate 24 hours to blend flavors. (Sausage links may be cooked immediately, refrigerated 3 to 4 days, or frozen for later use.)
Place 4 to 5 sausage links in a large skillet; pierce each link with a needle 3 to 4 times. Add water to skillet to depth of 1/2- inch. Cover and simmer over low heat 50 minutes or until lightly browned, turning occasionally. Slice and serve warm or use in other sausage recipes.