IIGDT World International Institute of
Geometric Dimensioning & Tolerancing
GD&T Chart per ASME Y14.5M-1994 History
In 1984, Dr. Hetland was contracted to train a core group of upper-level management representing design, metrology, manufacturing and tooling. The Company's training objective was to provide geometric dimensioning & tolerancing (GD&T) users with higher competencies and with emphasis placed on harmonization of GD&T across all departments to achieve highest production efficiency. This initiative was brought forth by acknowledging the criticality of doing projects right the first time.

“On-site” training was facilitated in a dedicated room of average size, with a unique whiteboard that encompassed the perimeter of the room. The training was highly interactive due to the involvement of many participants with different reference experiences of GD&T based on their past training, personal utilization, various competency levels and spanning multiple departments.

Dr. Hetland's training involved specific discussion covering the 13 geometric symbols (per ANSI Y14.5M-1982), their optimum place of utilization and their restrictions. Many participants raised questions in need of clarification of meaning, application and relationship of each symbol, resulting in whiteboard examples showing each of their symbols and derived boundaries.

The training concluded with participants performing a 360-degree gradual recap of facts and reinforcements of Dr. Hetland's examples, showing amazement by the magnitude of information covered in a few short days and acknowledged their unprecedented comprehension of the symbols and progressive graphical representation of derived boundaries. Most rewarding to Dr. Hetland was when many of the participants turned to him and said, “I finally get it.

That evening Dr. Hetland realized there was merit in a reference tool that captured the “whiteboard” information and that such a tool could also benefit other companies seeking similar solutions. Hence, the original GD&T Chart was created.

Today, Dr. Hetland has shown thousands of new and experienced users the power of optimum utilization and integration of GD&T, resulting in higher precision in interpretation and application of GD&T across all disciplines. Paradigm shifts have occurred from a moderate consideration of GD&T to becoming the highest value-add priority. Companies around the world today use the GD&T chart for sanity checks, quick reference, student reinforcement and problem solving.

Dr. Hetland continues his pursuit of higher precision and global simplification, which has resulted in taking the now 14 geometric symbols down to 3. Imagine!

These proven symbols are now the only ones needed to design, tool, manufacture and measure components and assemblies while complementing the highest of quality systems. These strategic breakthrough findings are fully covered in Dr. Hetland's newly launched series of public and onsite courses. See the Seminar section of the IIGDT website for course details.

Charts may be purchased online, click here.