M6 × 1.0
Tap drill
5 mm
5 mm · ≈77%
Major Ø
6
mm · 0.2362"
Pitch
1
mm · 25.4 TPI
Clearance
6.4/6.6/7
close/normal/loose mm
Shop tool · free
Tap drill calculator
Pick a thread and get its recommended tap drill, clearance hole and key dimensions instantly. Every value is generated from the standard formula, not a hand-typed chart.
How the tap drill is worked out
Metric: the recommended drill follows the standard rule tap drill = D − P (major diameter minus pitch), which reproduces the published charts — an M6×1.0 taps at 5.0 mm — and lands at roughly 77% thread engagement.
Unified: the theoretical 75%-thread diameter D − 0.9743/TPI is snapped to the nearest standard fractional, number or letter drill. A 1/4-20 UNC works out to a #7 drill, exactly as the handbook says.
Clearance holes for metric sizes are the ISO 273 fine/medium/coarse values; Unified clearances follow the common shop rule of nominal + 1/64" / 1/32" / 1/16" to the nearest drill.