Tap drill chart for ISO metric coarse and fine threads (drill = major diameter − pitch).
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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Tap drills — ≈77%
Drill Ø = nominal − pitch, the standard metric chart value (≈77% thread). The sub-line shows the closest inch drill and the thread % it gives. Cut taps only. Tap a row to copy the drill size in mm.