SPRING 2024

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THE DISTRIBUTOR’S LINK
Laurence Claus
Laurence Claus is the President of NNi Training and Consulting, Inc. He has 25 years of
experience with a medium sized automotive fastener manufacturer, holding positions
including Vice President of Engineering, General Manager, Director of Quality, Director
of New Business Development and Applications Engineer. In 2012 he formed NNi
offering technical and business training courses as well as technical consulting, expert
witness and consultation work. He can be reached at 847-867-7363 or by email:
Lclaus@NNiTraining.com. You can learn more about NNi at www.NNiTraining.com.
HOW FASTENERS ARE MADE - PART 2
HOT HEADING AND SCREW MACHINING
I recently taught a class to a group of engineers
on Geometric Dimensioning and Tolerancing (GDT).
This topic is easily one of the most misunderstood
and problematic topics that fastener manufacturers
and suppliers wrestle with. When I teach this class, I
inevitably comment to participants that we should not be
too surprised that our customers make GDT demands of
us that are often challenging and sometimes impossible,
simply because they do not know any better. They do
not know how fasteners are made and, thus, ask for
requirements that are difficult or impossible for us to
fulfill.
Sadly, our customers are not the only ones guilty
of not knowing about how fasteners are made. It is
quite easy for distributors that only work with finished
parts to not really understand the processes employed
to make them. This is unfortunate since even a basic
understanding of how fasteners are manufactured will
make those selling and interfacing with customers about
fastener products that much more knowledgeable and
helpful.
Most fasteners are formed using a process called
Cold Heading. Part 1 of this series explained why
cold heading is the favored process for fastener
manufacturing. Although cold Heading has a number
of important advantages, the speed, minimal waste,
and ability to form net or near net shape blanks really
TECHNICAL ARTICLE
sets it apart from all other processes used to form
fasteners. As remarkable a process as cold heading is,
what happens when you desire a part larger or longer
than the largest cold heading machines can produce, or
a part made from an exotic material that is difficult to
form at room temperature, or when only a few parts are
needed? In these instances, cold forming may not be the
best answer.
For this reason, discussion on this topic of how
fasteners are made would be incomplete without
looking at the other two common methods of producing
traditional threaded fasteners, hot or warm heading and
screw machining. Part 2 of this series will do just that
and look at the basics of Warm and Hot Heading and
Screw Machining.
Warm And Hot Heading
Everyone knows from some personal experience
that warming certain materials up makes them easier
to work with. Consider a hot glue gun, the glue stick
at room temperature is soft and can be easily bent in
different directions, but ineffective at gluing anything.
It is not until heat is added that the glue becomes soft
enough to function as glue. In a like manner, heat allows
the metals used to make fasteners more formable, and,
thus, becomes a valuable tool in our arsenal pf forming
methods.
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