Bosch Tap and Drill Bit Combo Sets are an easy way to ensure drilling the proper hole size before cutting internal threads. Plug taps are ideal for cutting right-hand internal threads; they are the most widely used type of tap, with three to five threads chamfered for general-purpose applications. The included drill bit is matched to the tap for the proper hole size. The bit is designed with split points to reduce bit walking for clean, accurate starts. The bit’s speed helix design promotes fast drilling. The plug tap is recommended when there is sufficient room on a blind hole and tapping to the bottom of a hole is not critical. Made from heat-treated carbon steel, it is a rust- and tarnish-resistant tool. The rolled threads are more accurate and cleaner than machined threads. They are tooled to the most exacting specifications to ensure that bolts anchor securely. Laser-etched marking ensures size identification and won't wear off. They feature a precise flute design to ensure fast and easy chip clearance.