Tap Drill Size
Compute tap drill diameter D before tapping (≈ d − P) from nominal d and pitch P.
Inputs
Formula
D ≈ d − P
Ductile materials may use slightly smaller to keep thread height.
Fundamentals
Compute tap drill diameter D before tapping (≈ d − P) from nominal d and pitch P.
This tool computes Tap Drill Size from the formula: D ≈ d − P
History
Manufacturing evolved with machine tools and CNC; cutting-parameter calculation is central to process planning.
Engineering applications
Used for cutting parameters, tooling and forming process design.
Glossary
| Nominal d | Input parameter |
| Pitch P | Input parameter |
| Tap drill D | Output result |
How to use
- Fill in Nominal d, Pitch P in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Tap drill D in the results area.
Formula · Worked Example · Knowledge
Formula
核心计算关系：D ≈ d − P
输入变量：
- Nominal d
d— mm - Pitch P
P— mm
输出结果：
- Tap drill D
D— mm
假设/适用：Cutting params (v, f, a_p) must stay within tool/workpiece recommended windows.
Worked Example
根据公式 D ≈ d − P，取 Nominal d = 10 mm；Pitch P = 1.5 mm。
代入计算得：Tap drill D = 8.5 mm。
Key Points
- Cutting params (v, f, a_p) must stay within tool/workpiece recommended windows.
- MRR scales with feed speed, depth and width; sets required spindle power.
- Feed f = f_z·z·n; match per-tooth feed with spindle speed.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Nominal d (mm) | d | mm | 10 |
| Pitch P (mm) | P | mm | 1.5 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Tap drill D | D | mm |
Applications
- Cutting parameters and speed
- Gear measurement (3-wire/base tangent)
- Blanking and deep-drawing process
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: D ≈ d − P
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Cutting parameters and speed