: Specifically for bolts, screws, and similar parts with an external metric thread. Dimensions
DIN 76-1 is a standard published by the Deutsches Institut für Normung (German Institute for Standardization). It specifies the dimensions and design of thread run-outs, thread undercuts, and thread ends for ISO metric screw threads. Thread Run-out vs. Thread Undercut
: Covers the overarching specifications for metric coarse and fine threads.
Here is the summarizing the key content of DIN 76-1 as found in the standard (not the PDF file itself, but the data you would extract from it): din 76a pdf
: Manages dimensions specifically engineered for pipe threads conforming to international ISO 228-1 frameworks.
You can find the PDF here:
refers to a specific type of thread undercut for fasteners, defined under the broader : Specifically for bolts, screws, and similar parts
| 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) |
2.5), engineers rely on the dimensional tables inside the to ensure the exact radius and width match the requirements of their mechanical drawings. Why the DIN 76A Standard is Critical
, typically used when the distance to the bearing face must be minimized. It requires special tooling due to its narrower width. : The standard design for internal threads (blind tapped holes). : A "short" design for internal threads , used when space at the bottom of a hole is limited. Technical Specifications Thread Run-out vs
A properly machined undercut distributes stress more evenly, reducing the risk of fatigue failure at the sharp transition zone.
) : For Form A, the width is typically around .
unless space or functional constraints demand a shorter undercut. Form A works with standard cutting tools, keeping manufacturing costs predictable.