E-Z Knife 1/4-20 Threaded Insert Kit - Stainless SteelE Z Knife Threaded Insert Kit provides an easy solution for adding machine threads to hardwoods like Oak, Cherry and Maple. It can also be used for softwoods, but it is not recommended for plywood. A proprietary external thread give the insert superior holding power. Features: For hardwood or softwood Not recommended for plywood Easy solution for putting strong, machine threads in wood Ideal for cabinetry, furniture, display cases anywhere a threaded