For projects that will stay indoors, go with standard pocket screws. Kreg Zinc Screws provide rust protection, and are well-suited for indoor projects of all types that won’t be exposed to excessive moisture. Hardwoods like oak, maple, and cherry, on the other hand, are too hard and dense for coarse-thread screws. The aggressive threads tend to tear the wood fibers, which can result in splits in your wood. For these hardwoods, choose Fine Kreg Screws. The threads are less aggressive, but there are more of them to ensure great holding power without splitting Woods like pine and spruce as known as softwoods. They are not very dense, so they need a screw with deep, aggressive threads that will bite into soft fibers. Coarse Kreg Screws work great for these woods, and are also the preferred choice for sheet goods like plywood and MDF.