A man sits by a work bench with a metal frame on it.

An Airtight Case: Custom Fabrication for a Medical History Treasure

Robert Clary is a machinist in the Mechanical Instrumentation Design and Fabrication Branch, part of the Division of Scientific Equipment and Instrumentation Services (DSEIS) in the Office of Research Facilities (ORF) at the National Institutes of Health (NIH), which provides custom instrumentation, equipment design, fabrication, and modification services.

Circulating Now: Tell us about your typical work in the Mechanical Instrumentation Design and Fabrication shop.

Robert Clary: Many of the projects that I work on here at NIH are of the quick fix type.  Usually some problem has developed with a researcher’s device that I am asked to remedy.  Other times, I am asked to design and fabricate a novel idea or design.  Those are certainly the most rewarding projects.  A few times in my career, I have been fortunate enough to help out with some very high profile projects such as the Marshall Nirenberg Charts.

A man fits a heavy sheet of glass over a metal frame.
Robert Clary of NIH Fabrication modified the commercially available frame, set up and constructed necessary components for the argon system, and trained NLM staff on the argon transfer process.

CN: How do you feel about being a part of the team that worked to preserve the Marshall Nirenberg Charts, the Rosetta stone of modern science, according to some?

RC: It is quite an honor to be asked to help preserve something as important as the Marshall Nirenberg Charts.  Humanity’s road to scientific literacy certainly has its share of milestones.  When those milestones have accompanying documentation, preservation of those documents will ensure future generations have access to the physical artifacts that have shaped their world.  A well-documented and preserved history of science is essential to predicting and forming future research pathways.

CN: What was challenging about about creating anoxic (oxygen-free) microenvironments for these cherished documents?

RC: I would have to say one thing—viewing windows!  The simplest chamber design would be a six sided box of say, stainless steel.  That would make the design and fabrication relatively simple.  It also has the added benefit of preventing high energy photons from entering the chamber.  The reality is that these protected documents still need to be ‘visibly displayed’ to the public.  So viewing windows are a requirement.  The crux of the problem becomes how to bond glass to metal without leaks, and remain leak free for many years, decades, or even centuries.

A chart in its oxygen-free case.
The enclosure is constructed from aluminum, glass, and o-rings. Argon levels will be monitored to establish a long term maintenance schedule.

In addition, the best designs should consider all of the following potential causes of damage:

  • Chemical: Any chemical compounds that will cause changes to the document/ink
  • Electromagnetic: Stray voltages
  • Photoelectric: High energy photons(UV)
  • Thermal: Too much heat, too many thermal cycles, or extreme thermal cycles.
  • Vibrational: Any motion whatsoever
  • Physical/Mechanical: Document must be protected from accidental as well as intended physical harm
  • Pressure: Variations in pressure can have similar affects as thermal and vibrational influences.
  • Display orientation in earth’s gravity: Documents must be displayed in a way that their own weight doesn’t cause damage

CN: This isn’t the first unique historical document you’ve worked to protect, tell us about one of your other projects.

RC: Charters of Freedom – In the 1950’s, NIST (US Dept. of Commerce, National Institute of Standards and Technology) was tasked with encasing the United States Declaration of Independence, Constitution, and Bill of Rights.  By the early 90’s, it was apparent that those original encasements were not going to protect the documents in the way that the designers intended.  So NIST was asked to re-encase these documents in the mid 1990’s.  I joined the project around 1996-1997.  One of the most impressive things about the entire project was how well everyone worked together.  The Archivists, Conservators, Scientist, Technicians, and Managers all had a very clear goal in front of them.  That goal was to build the best encasements possible.  Once the project was begun, I found myself trying to help very smart people do very difficult things.  It was decided that the encasements would be actively monitored for H2O and O2 content.  Two independent systems would be used for this purpose, a traditional electronic sensor package and a separate system based on absorption spectroscopy.  Most of my time on the project was spent on the absorption spectroscopy system.  It was a fascinating time and conditions were perfect.  ie; large project, eager staff, clear goal, ample funds.

To be involved in something like the Charters of Freedom project is a very high honor.  It is awe inspiring to witness a large scale project through to completion.  However, It is a slightly uneasy feeling when you deliver a product that is expected to last hundreds of years.  I can only hope that my small contribution to the project made a difference.

CN: How did you start on your path to becoming a machinist. 

RC: The year was 1987.  I was a high school freshman.  My older brother was a senior at the same school.  He had decided to take the new Diesel Mechanics class that was going to be offered that year at a brand new classroom, still under construction at the Carroll County Vocational Technical School in Westminster, MD.  However, just prior to the start of the school year, an unfocused bulldozer operator knocked down a large section of wall.  This delayed the start of the Diesel Mechanics program by about 4 weeks.  All of the students were informed that they could pick any other class offered at the Vocational Technical School until the construction was complete.  My brother chose the Machine Shop class.  However, by the time the repairs to the Diesel Mechanics classroom were complete, he had become enthralled and opted to stay in the machine shop program.  At that time in my life, I simply wanted to do what he was doing.  So, 2 years later, I enrolled in the very same program.

In 1990, I was offered a co-op position in the machine shop at the National Institute of Standards and Technology.  The rest, as they say, is history.  We are both still machinists.  Although he did one-up me by becoming a Tool and Die Maker, a much more specialized version of a machinist.

Read more about Conservation at the National Library of Medicine and about Marshall Nirenberg and the work to preserve his Genetic Code Charts.


  1. Thanks. I hope my fellow ergonomist have a chance to read this article. The best designers, I’ve found, carry this stuff in their heads as they work. Testing,testing and of course testing.

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