Drill and tap calculator
Get drilling RPM, penetration rate and drill-point allowance, then look up the right tap drill for the thread you need.
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What it covers
- Drilling RPM and feed per revolution with spindle limit
- Drill-point allowance from point angle
- Tap drill sizes for UNC, UNF and metric coarse/fine
- Cutting-only time, with pecks and rapids clearly excluded
Common questions
- What tap drill do I use for 1/4-20?
- A #7 drill (0.201 in) gives roughly 75% thread. Open the tap drill chart for every size.
- How is drill point length calculated?
- Point length = (D ÷ 2) ÷ tan(point angle ÷ 2). A 118° point is about 0.3 × D.