Standard NPT pipe tap drill chart with threads per inch for each size.
Reference aid — verify before you cut. Thread data per ASME B1.1 (Unified), ASME B1.8 (Stub Acme) and ISO 965 (metric M profile); charts cite their source in each tool. Formulas and data are checked against published standards, but errors and edge cases are possible — always confirm critical dimensions against the controlling standard or a calibrated gage before machining. No warranty; use at your own risk. Tap the star on a tool to favorite it.
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NPT tap drills
Tapered pipe thread (NPT / NPTF). Tap drill is the cut-tap chart size, no reaming — for a tapered reamer finish, drill one size under and ream. Thread it only hand-tight plus 1–2 turns. Tap a row to copy the drill Ø.