TDC of Arizona, Inc. instructors are GDTP certified by ASME in accordance with the qualifications of ASME Y14.5.2 in the Senior Level

Meet Our Instructors

All TDC instructors are certified ASME Senior Level Geometric Dimensioning and Tolerancing Professionals (GDTP), and have taught hundreds of workshops within the USA and abroad.

Michael A. Sandford


Michael A. Sandford began use of GD&T as a mechanical engineer with a major aerospace company in 1983. He has been instrumental in the creation and technical review of design documentation for over 31 years.

Mr. Sandford has extensive experience in the design, fabrication, assembly, and test of a wide variety of mechanical components, such as optical items, structural components, test equipment and fixturing, motors, bearings, etc. Using GD&T for the design of mechanical hardware has enabled Mr. Sandford to design, assemble, and test hundreds of parts successfully. He is familiar with the many fabrication processes of mechanical components including forgings, castings, weldments, injection molded plastic parts, diamond-turned optical items, and sheet metal parts, as well as standard machine shop processes. He is well acquainted with machine shop practices and inspection techniques.

Mr. Sandford has a BS in Mechanical Engineering from New Mexico State University and a MS in Engineering Mechanics from the University of Arizona. He holds several patents for various mechanical devices and he is a member of the American Society of Mechanical Engineers (ASME), the Society of Allied Weight Engineers (SAWE), the American Institute of Aeronautics and Astronautics (AIAA), the Society of Automotive Engineers (SAE),  and is a certified ASME Senior Level Geometric Dimensioning and Tolerancing Professional (GDTP S-0356).

Mr. Sandford is the owner of TDC and serves as the main instructor for the various GD&T training programs. He has instructed thousands of students over the past thirteen years in the proper use of GD&T in accordance with the ANSI Y14.5M-1982, ASME Y14.5M-1994, and the recently released ASME Y14.5-2009 standard.

George O. Pruitt


George O. Pruitt, a popular and respected leader in the field of GD&T training, founded Technical Documentation Consultants, Inc. (TDC) in 1984.

He began by teaching GD&T courses at Cerro Coso Community College in Ridgecrest, California. He also supervised the Geometric Dimensioning and Tolerancing Office at Naval Weapons Center, China Lake, California, where he promoted the proper application and interpretation of GD&T to government and contract personnel.

Mr. Pruitt's extensive background in product design, manufacturing, tool and gage design, and quality control allowed him to tie GD&T concepts together from engineering to production and inspection. He recognized that GD&T must be properly applied throughout the entire production team to be effectively used within a company. His strong belief in formal GD&T training led to the creation of TDC. Over the years, Mr. Pruitt has trained thousands of students in hundreds of companies.

Although Mr. Pruitt is retired and is no longer a full-time instructor, he continues to act as an advisor and technical consultant to TDC of Arizona.