The new ISO 14405-1:2025 is here! An update from ISO-GPS World!
Fans of geometrical tolerancing – and those who are about to become fans (or have to 😉) – can look forward to exciting news.
One of the most important standards following ISO 8015, ISO 14405-1 — the central standard for the dimensional tolerancing of linear sizes — has just been released, replacing the 2017 edition.
First things first: We won’t leave you alone with these changes – promised!
What’s New?
New syntax rules:
The order of size specification modifiers has been updated. “Portion” modifications now precede the size specification – no longer follow it. The same applies to the “CT” (common tolerance) indication. This means that in many cases the changes will be instantly noticeable when looking at new technical drawings.
Stacked tolerances:
Now clearly defined and, in certain cases, even necessary – for example, when the upper and lower tolerance limits include different modifiers (e.g. GX and GG).
Filter modifiers:
Like according to ISO 1101, it is now permitted to include indications for filter modifiers (ISO 16610-XX). You may be wondering how this could be useful in the practical application of geometrical tolerancing?
Imagine a requirement for a diameter with the envelope requirement applied, combined with a tolerance of T = 0.015 mm. What happens in terms of conformity evaluation (see also ISO 14253-1) if this feature is allowed to have a surface roughness of, for example, Rz 8? Exactly — we run into a verification challenge (especially in borderline cases of conformity and non-conformity). For this, one does not even need to consider any potentially applicable 16% rules (see also ISO 21920-1 and ISO 1302) to end up in a conflict within a customer–supplier relationship.
That’s why you’ve come to the right place: on our platform, we help you deepen your understanding of real-world geometrical tolerancing applications through every available ISO-GPS practice example.
Other Changes:
- Harmonized indication rules for pattern specifications according to ISO 5458 (e.g., 2×A / 5×B).
- Clarified (stricter) rules for indicating SCS, e.g. ensuring compatibility with MBD/PMI (machine-readability) environments.
Our Service for You:
From now on, every new ISO-GPS application example on www.gps-practice.com will consider these changes.
Knowing that the many new rules may raise questions — and perhaps even cause some uncertainty — among users of the ISO GPS standards system, we have prepared a special overview of the new syntax rules for you. This exclusive resource is now available to all registered users on our platform.
Simply visit our ISO-GPS Practice Example Shop and look under the “Übersichten / Overviews” category to download your free copy of the brand-new ISO 14405-1:2025 rules!
Conclusion:
New rules, new possibilities – and we’ll help you master both.
Experience is the foundation for success.
Marcus Grella, GRE-TEC, training.engineering.practice