Screws | Canadian Tire- zinc screws in treated wood ,Hillman Flat Head Zinc Wood Screw Set, 1-1/2-in, 300-pc. #161-7506-2. (9) 4.4 out of 5 stars. 9 reviews. In-stock. FEATURES. Hillman Flat Head Zinc Wood Screw Set is typically used for interior applications. Robertson (square) drive reduces "cam out". Convenient screw top jar for storage.What Are Galvanized Screws Used For? | HunkerTreated wood, which is prized for its resistance to fungal decay and insect attacks, is created by forcing chemical preservatives into boards through a vacuum and pressure process. The problem is that the same preservatives that extend the life of lumber, attack and destroy the integrity of traditional steel screws.