Use scrap wood to form plugs. Snappy Plug Cutters are tapered so they form a tight fit. For best results, always bore to the maximum depth of the cutter. Once you drill the plug, simply pop it out with a screwdriver then insert the chamfered end in the hole and tap with a hammer. Trim remaining plugs flush to the surface. Recommended drill speed is 800 - 1,000 RPM. This set includes one each: 1/4", 3/8", and 1/2" plug cutters with 1/4" hex quick-change shanks. Made in USA.