There is an interesting but incomplete 2026 book by Alex Davies titled Kobuk the Destroyer and other tales from the wild, unseen world of test engineering. (Kobuk is a problem grizzly bear at the Grizzly & Wolf Discovery Center, who is an expert at defeating products that should be bear-resistant). Google Books has a preview from this book. Alex begins describing it on page 5:
“Implementing an idea hinges on, among other things, proving that whatever ends up in the consumer’s hands will actually work, reliably and safely. That the thing will hold its form and perform its function for years or decades. That when it breaks, it won’t send razor-edged shards flying. That it will blunt the consequences of the inevitable errors of the humans that use it, interact well with its environment, and work in a way that its users expect and desire. Doing all that requires the ability to foresee and forestall the novel modes of failure that arrive with every innovation. That work falls most often not to the inventor, but to the test engineer.
The test engineer gets little attention in a world that lionizes inventors, and that’s a shame – not just because their work involves chicken cannons, flamethrowers, and mischievous grizzly bears, and not just because they rely on the same ingenuity, foresight, and creativity that fits the inventor stereotype. It’s a shame because they are the ultimate fixers, the people who turn inventions into products by earning and rewarding the public’s trust.
This book is about their work as it plays out in myriad times and places, with manifold products and test regimes and industries. It’s about the people and the machines and the laboratories and the standards and the cultural mores, the measurement and mimicry of reality, the passing of judgment, and the occasional shrug of the shoulders in the face of unending complexity. It’s about approximating the inevitable and the near impossible: how pilots will mix up instrument controls and how turbulence might snap plane wings. It’s about avoiding not just the obvious disasters (the levee that crumbles) but the equally catastrophic and stupefying ones (the tsunami that overtops the dam). It’s about creating systems for doing that work – systems that, like the people who make them, are fallible but can deliver success despite their imperfections.
It's about failure and failure and failure and fleeting interregnums of success. It’s about how knowledge is formed, how rules are written and enforced, how good things are made and bad things made good. It’s about accepting – whether due to pain, disaster, or a honey-smeared bear snout – that our best efforts are not always good enough. It’s about how we adapt to that fact by balancing risk against reward, utility against safety, progress against hesitancy.
It's about how we construct our world, because testing forms the backstory and backbone of every thing in our lives.”
And on page 15 he continues:
“THE BEST PATH TO SUCH AN ENLIGHTENMENT IS NOT TO STUDY one product after another – cars, planes, toys, and so on – but to break this work down by the kinds of failure that test engineers regularly confront and plan for. We’ll look at six different concepts, each of which encapsulates ways in which a product can boom or bust.
The first is limits, in which testing determines strength and durability – like whether a bridge can withstand being hit by a container ship, or whether your space bar will give out before your laptop does. The second is fool-proofing, which is about preventing user error, from kids getting into medicine bottles to lawn mowers lopping off toes. When failure does strike – when cars crash and fires start – disintegration testing ensures that the product in question minimizes the damage. Scale comes into play when the focus shifts from one product to many, where ground beef is scanned for disease and vaccines checked for impurities. Our penultimate chapter is about dynamics, which considers how a product will impact the world around it, and vice versa. This is where Formula I cars capture the wind and engineers redirect the Mississippi River to buoy the sinking Louisiana coastline. Finally, we’ll close with intention. This trickiest of all concepts asks not whether a product functions as it’s designed to, but whether it produces the desired result. As new technologies – artificial intelligence chief among them- push everyone into a new frontier, we’ll see how our pioneering test engineers keep up by combining old knowledge with new techniques.”
Chapter titles and their starting pages are:
Introduction – Bear Contact Time 1
Chapter 1 – Limits 17
Chapter 2 – Fool-Proofing 49
Chapter 3 – Disintegration 79
Chapter 4 – Scale 117
Chapter 5 – Dynamics 145
Chapter 6 – Intention 175
Conclusion – The Total Test Environment 197
What is missing from this book? Alex mentions some standards organizations – Underwriters Laboratory (UL), the American National Standards Institute (ANSI), the U. S. Consumer Product Safety Commission (CPSC), and very briefly the Society of Automotive Engineers (now SAE International).
But he does not mention either what was the American Society for Testing and Materials (now ASTM International) or the International Standards Organization (ISO). Standards produced by these organizations define a wide variety of products. And typically, a product standard cross-references a constellation of other standards.
If you look for the strongest standard steel bolts or cap screws at stores like Home Depot or Lowes, you will find them in a drawer labeled Grade 8. As shown above, typically they will have a bronze color from zinc plating, and the head will have six lines in a hexagonal pattern to identify them, along with a manufacturer mark (in this case SJ). The standard for them is SAE J429: Mechanical and Material Requirements for Externally Threaded Fasteners (most recently dated 2014-05-06). You can read a pdf file of the 1999 version here. That standard defines a very specific recipe for making Grade 8 fasteners – their composition, processes and the resultant properties. The description summary says:
“This SAE Standard covers the mechanical and material requirements for inch-series steel bolts, screws, studs, screws for sems, and U-bolts in sizes to 1-1/2 in. inclusive.
The term ‘stud’ as referred to herein applies to a cylindrical rod of moderate length threaded on either one or both ends or throughout its entire length. It does not apply to headed, collared, or similar products which are more closely characterized by requirements shown herein for bolts.
The mechanical properties included in Table 1 were compiled at an ambient temperature of approximately 20 °C (68 °F). These properties are valid within a temperature range which depends upon the material grade used and thermal and mechanical processing. Other properties such as fatigue behavior, corrosion resistance, impact properties, etc., are beyond the scope of this document and responsibility for ensuring the acceptability of the product for applications where conditions warrant consideration of these other properties shall be borne by the end user.”
J429 cross references the following six other SAE standards:
SAE J403: Chemical Compositions of SAE Carbon Steels.
SAE J404: Chemical Composition of SAE Alloy Steels.
SAE J409: Product Analysis – Permissible Variations from Specified Chemical Analysis of a Heat or Cast of Steel.
SAE J123: Surface Discontinuities on Bolts, Screws, and Studs.
SAE J417: Hardness Tests and Hardness Number Conversions.
SAE J121: Decarburization in Hardened and Tempered Unified Threaded Fasteners.
J429 defines a very specific recipe for making Grade 8 bolts. The chemical composition should allow heat treatment by quenching to produce a minimum of ninety percent martensite (monitored via the as-quenched hardness). Then the fasteners are tempered at a minimum of 800 oF. Threads are formed by rolling.
Grade 8 has a minimum yield strength of 130,000 psi, and a minimum tensile strength of 150,000 psi. Elongation is a minimum of 12%, and reduction in area is a minimum of 35%. And the Rockwell hardness range is 33 HRC to 39 HRC. (39 HRC converts to a maximum tensile strength of 177,000 psi).
The next lower bolt grade (also quenched and tempered) is Grade 5, which is denoted by a head with three lines in a triangular pattern. Grade 5 has a minimum yield strength of 92,000 psi, and a minimum tensile strength of 120,000 psi. Elongation is a minimum of 14%, and reduction in area is a minimum of 35%. Rockwell hardness range is 25 HRC to 34 HRC. (34 HRC converts to a maximum tensile strength of 152,000 psi).
Back on November 4, 2017 I blogged about Ten years of experience, or one year’s experience ten times? In that post I discussed SAE Standard J1401 – Road Vehicle – Hydraulic Brake Hose Assembles for Use with Nonpetroleum-Base Hydraulic Fluids. It included incorporating marker yarns (to identify the hose manufacturer) along with the reinforcing braid. And using marker yarns was spread to other types of hoses.
The grizzly bear image came from Wikimedia Commons.
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