Utilizes standard XML definitions to automatically generate the geometry. Alternatives to Form A
Accessing detailed engineering data is crucial for precise manufacturing and design, which is why engineering professionals frequently seek out the . DIN 76 is the German Institute for Standardization (Deutsches Institut für Normung) specification that outlines the standardized dimensions for thread run-outs and thread undercuts (also known as relief grooves). Specifically, the "Form A" designation within this standard refers to a specific geometry applied to external threads (such as bolts) to facilitate safer and more precise machining and assembly.
| Thread Size (M) | Pitch (P) | Undercut Width (a) | Undercut Diameter (d₂) | | :--- | :--- | :--- | :--- | | M3 | 0.5 | 0.8 mm | 2.2 mm | | M6 | 1.0 | 1.6 mm | 4.6 mm | | M10 | 1.5 | 2.5 mm | 8.0 mm | | M20 | 2.5 | 4.0 mm | 17.0 mm | din 76a pdf
: Form A is a "normal" length undercut. It ensures the threading tool has enough room to exit cleanly, leaving only full, usable threads behind it.
| Design Need | Recommended Form | | --- | --- | | Normal external thread, no special space constraints | Form A (DIN 76-A) | | Tight space on shaft, acceptable to use special tools | Form B (DIN 76-B, case‑by‑case) | | Internal (blind) thread | Form C (DIN 76-C) | Specifically, the "Form A" designation within this standard
DIN 76A is a German standard for a specific type of threading, known as a "Metric Thread with a 60-degree angle and a flat crest." The standard is published by the Deutsches Institut für Normung (DIN), a German national standards body. DIN 76A defines the dimensions, tolerances, and testing methods for metric threads with a 60-degree angle and a flat crest.
Example for M10 x 1.5 (Pitch = 1.5mm):
| Pitch ( P ) (mm) | Width ( b ) (mm) | |--------------------|--------------------| | 0.2 – 0.5 | 0.5 – 1.0 | | 0.6 – 1.0 | 1.0 – 1.6 | | 1.25 – 1.75 | 1.6 – 2.5 | | 2.0 – 3.0 | 3.0 – 4.0 | | 3.5 – 5.0 | 5.0 – 6.0 |
What (e.g., M8 x 1.25) are you currently designing? | Design Need | Recommended Form | |
: The undercut's width and depth are strictly calculated based on the thread pitch (P) Comparison