Irwin tap and drill bit combo pack for cutting machine screw threads. Includes a high carbon steel plug tap for general-purpose threading and a high-speed steel (HSS) drill bit sized for the correct tap drill hole. Having the matched set ensures proper thread fit every time.

• Tap size: 5/16"-18 NC
• Drill bit: Letter F (17/64")
• High carbon steel plug tap for general-purpose threading
• High-speed steel (HSS) drill bit for fast, precise drilling
• Matched set delivers the correct tap drill diameter
• Use cutting oil on steel; tap dry or with kerosene on aluminum and cast iron

Tip: Drill the pilot hole with the matched HSS bit, then back the tap out a quarter turn every full turn to break the chip and prevent the tap from binding or snapping.