Din 76-a | Pdf

When designing mechanical components, engineers often focus heavily on the thread tolerance, pitch, and diameter. However, one critical aspect that is frequently overlooked is the thread runout (or thread undercut). This is where DIN 76-A comes into play.

If you are looking for the DIN 76-A PDF to reference the exact dimensions for your technical drawings, this post breaks down what the standard covers and why it is essential for manufacturing quality.

DIN 76-1 is a German (DIN) standard that defines the dimensions and types of thread run-outs (the transition area between a full thread and a plain shaft) and thread undercuts (relief grooves) for metric ISO threads as specified in DIN 13 (e.g., M series threads). din 76-a pdf

The goal is to ensure that a threaded part can be manufactured (e.g., by turning or grinding) and assembled without interference, while maintaining predictable strength and fit.

Note: The "A" you mentioned likely refers to an older version (e.g., DIN 76-A) or a specific form. The current unified standard is DIN 76-1. (DIN 76-2 covers fine pitch threads.) Note: The "A" you mentioned likely refers to

| Thread size (M) | Pitch P (mm) | Undercut width a (mm) | Undercut depth t (mm) | |----------------|--------------|------------------------|------------------------| | M3 | 0.5 | 0.8 | 0.15 | | M4 | 0.7 | 1.0 | 0.20 | | M5 | 0.8 | 1.2 | 0.25 | | M6 | 1.0 | 1.5 | 0.30 | | M8 | 1.25 | 1.8 | 0.35 | | M10 | 1.5 | 2.0 | 0.40 | | M12 | 1.75 | 2.5 | 0.50 | | M16 | 2.0 | 3.0 | 0.60 |

Values are for illustration only. For precise engineering, download the official standard. | Thread size (M) | Pitch P (mm)

The standard defines two main forms:

Ignoring DIN 76-A can lead to three major problems: