Start with the drawing
The nominal diameter, pitch, thread direction, starts, tolerance class, engagement length, surface treatment, and acceptance requirements belong in the specification.
INDUNECT / KNOWLEDGE / RF-001DERIVED REFERENCE
Metric threads.
Geometry, not copied tables.
Enter the thread designation inputs and generate basic 60° profile geometry, lead, and a workshop tap-drill starting estimate. Tolerance-class limits remain outside this page and must come from an authorized standard.
FORMULA DERIVEDINPUTS VISIBLESTANDARD BOUNDARY STATED
01REFERENCE SCOPE
WHAT THIS PAGE DOES
Useful dimensions from a transparent calculation.
This is an original calculation aid, not a reproduction of an ISO or DIN table. It distinguishes basic profile geometry from tolerance limits, manufacturing allowances, plating allowances, and inspection acceptance criteria.
INPUT / METRIC THREAD
Generate one reference row.
Boundary
No preferred pitch series, tolerance classes, limit deviations, gauge dimensions, bolt dimensions, or nut dimensions are reproduced here.
GENERATED DESIGNATIONM10 × 1.5
RF-001- Fundamental triangle
- 1.299 mm H = √3·P / 2
- Thread lead
- 1.500 mm/rev L = P·z
- Basic pitch diameter
- 9.026 mm d₂ = D₂ = d − 3H/4
- Basic internal minor diameter
- 8.376 mm D₁ = d − 5H/4
- Basic external minor diameter
- 8.160 mm d₃ = d − 17H/12
- Tap-drill starting estimate
- 8.500 mm D drill ≈ d − P · workshop rule only
02ILLUSTRATIVE ROWS
INDEPENDENTLY CALCULATED EXAMPLES
A small reference—not a standards extract.
The pitches below are four familiar workshop examples selected to demonstrate the formulas. The calculated columns are generated from the displayed diameter and pitch. Confirm the required thread designation in the governing drawing or authorized standard.
| Example | d | P | Lead | d − P estimate | Basic d₂ / D₂ | Basic D₁ |
|---|---|---|---|---|---|---|
| M6 × 1 | 6 mm | 1 mm | 1 mm/rev | 5 mm | 5.350 mm | 4.917 mm |
| M8 × 1.25 | 8 mm | 1.250 mm | 1.250 mm/rev | 6.750 mm | 7.188 mm | 6.647 mm |
| M10 × 1.5 | 10 mm | 1.500 mm | 1.500 mm/rev | 8.500 mm | 9.026 mm | 8.376 mm |
| M12 × 1.75 | 12 mm | 1.750 mm | 1.750 mm/rev | 10.250 mm | 10.863 mm | 10.106 mm |
03METHOD & LIMITS
USE WITH ENGINEERING JUDGEMENT
Basic geometry is not a manufacturing limit.
Use authorized tolerance data
Basic diameters are theoretical profile values. Actual maximum and minimum sizes require the applicable ISO 965 tolerance document or another governing specification.
Choose the drill for the process
The d − P result is a practical starting rule. Material, tap style, desired thread percentage, forming versus cutting, coating, runout, and toolmaker guidance can require a different drill.
Verify the machine cycle
Use CM-002 to plan synchronized feed and drilling motion, then verify the exact SINUMERIK interface and machine-builder documentation before running NC code.
04SOURCE BOUNDARY
OFFICIAL CONTEXT
Standards referenced, not reproduced.
ISO 68-1:2023 defines the basic and design profiles for ISO general-purpose metric screw threads. ISO 724:2023 covers the basic dimensions associated with metric fastening screw threads. This Indunect page provides original wording, independently evaluated geometry, and a limited set of illustrative calculations; it does not replace either publication.
Reference identity and publication status reviewed 26 July 2026. Always confirm the current applicable edition and project requirements.