Episode 68 — Engineering Expert


expertJames Trevelyan speaks with us about the skills and talents of expert engineers, and how those of us who have not yet achieved “expert” status can improve our ability to complete engineering projects on time and within budget.

  • Brian feels he is becoming less of an expert as time goes along; there just seems to be so much to know!
  • Our guest is James Trevelyan, a professor of Mechatronics Engineering at The University of Western Australia.
  • Some of our listeners may remember Dr. Trevelyan from Episode 19. (Yes, Jeff said Episode 17 during the podcast, but he was wrong!)
  • Dr. Trevelyan has recently published a book, The Making of an Expert Engineer.
  • Our guest mentions the book by Louis Bucciarelli, Designing Engineers, as one of the few sources of information about what engineers actually do on the job.
  • Engineering provides great opportunities for making the world a better place… and for spending other people’s money!
  • Research indicates that engineers have trouble delivering reliable and predictable results.
  • Carmen quotes the singer Meatloaf, noting that “Two Out of Three Ain’t Bad.”
  • James mentions the accomplishments of C.Y. O’Connor, an engineer who oversaw the construction of a water pipeline across uncharted regions of Australia in the late 19th century.
  • Our guest feels the skills needed to drive projects to completion have been largely lost as experienced engineers retire.
  • While Jeff longs to take engineering students out onto the factory floor, James indicates that some students aren’t particularly keen about participating in plant trips.
  • Engineers spend a lot of time teaching others, even if on an informal basis.
  • Peer instruction has proven effective in helping college students learn new material.
  • James mentions our prior interview with Dave Goldberg, in Episode 65.
  • Once again, we mention the Grinter report (pdf), which changed the course of engineering education in the United States.
  • ABET (Accreditation Board for Engineering and Technology, Inc.) is the organization that accredits most engineering programs in the United States.
  • James has spoken with corporate leaders who actively work to dismiss engineering employees, seeing the engineers as unable to produce predictable results.
  • Engineers have a reputation for being unable to communicate with those in other professions.
  • Listeners who are curious about accrual accounting are directed to Episode 34, Accounting for Engineers.
  • Expert engineers accurately forecast what can be done, then deliver on their promises.
  • An ability to avoid problems is often the mark of an expert engineer, and is more highly valued than the ability to solve problems.
  • “Prudent engineers build on past practice as much as they can.”
  • Engineers rely a lot on unwritten (implicit) knowledge.
  • Michael Polanyi was a philosopher who suggested that “we know more than we can tell.”
  • Explicit knowledge can be written down, and easily transferred; this type of knowledge forms the basis for much of what is taught in universities.
  • Expert engineers do not rely solely on their own knowledge, but know how to build on the knowledge and abilities of others.
  • Supplements to James’ book are available online, including a classification of engineering knowledge (pdf).
  • University grades don’t have much relation to engineering performance, at least as evaluated by supervisors.
  • Young engineers with an ability to obtain assistance from seasoned engineers are more likely to experience career success than are those who find themselves unable to garner expert support.
  • James hopes that senior engineers will begin cataloging concepts and ideas that younger engineers need to learn and understand.
  • One important skill that has been lost among the current generation of engineers is the art of writing of technical specifications.
  • While prior guest Dave Goldberg champions Noticing, Listening, and Questioning (NLQ), our current guest dedicates a chapter of his book to similar observational activities, which he designates the “three neglected skills:” listening, seeing, and reading.
  • We debated the relative merits of programming languages in Episode 64; James tells us that programming among engineers is most frequently performed with Excel (and its accompanying Visual Basic language).
  • James can be reached via his website: JamesPTrevelyan.com.

Thanks to Ruth Hartnup for the photo titled “Expert Ethan.” Podcast theme music by Paul Stevenson.

Episode 67 — Pragmatic


wrenchElectrical engineer John Chidgey joins us in this episode of The Engineering Commons to talk about ladder logic, podcasting, and an engineer’s role in making the world a better place.

  • An open invitation to discuss general engineering issues got Jeff started in the world of podcasting.
  • Carmen, Brian, and Adam became trapped involved as co-hosts on this podcast when Chris Gammell left the show.
  • Our guest for this episode is electrical engineer John Chidgey, who has worked in several engineering domains, including RF hardware, systems engineering, and the oil & gas industry. He also produces a weekly podcast, Pragmatic, and authors the Tech Distortion website.
  • Carmen and John are fans of making coffee with the Aeropress.
  • Citizens band (CB) radio served to interest John in electrical engineering.
  • John notes that there is a general trend toward standardization, as the costs of customization are too high for many companies.
  • For a while, at least, John had a job that may (or may not have) required a security clearance.
  • Our guest moved into the controls industry around 2003, installing programmable logic controllers (PLCs) for industrial clients.
  • Many PLCs can be programmed using ladder logic, which originally was nothing more than a schematic for wiring together electromechanical relays.
  • John has had some bad experiences programming PLCs with software implementing function block diagrams.
  • “Where there is a choice, there is a problem.”
  • After testing out several other podcast concepts, John launched the Pragmatic podcast to cover engineering topics in a practical and actionable manner.
  • John mentions the Hypercritical blog, written by John Siracusa.
  • Carmen is excited to read the recent OS X 10.10 Yosemite review that John Siracusa wrote for Ars Technica.
  • “Engineering is all about tradeoffs.”
  • In additional to covering technical topics, John’s podcast sometimes covers non-technical issues like weather forecasting and coffee.
  • John reveals that he loves using whiteboards.
  • A live chat room has recently been added as a feature of the Pragmatic podcast. Jeff doesn’t think he could handle the additional cognitive load while recording interviews.
  • We’ve gone meta with a podcast about podcasting!
  • John occasionally gets requests for career advice, although many times engineers write in to simply point out technical errors.
  • According to our guest, engineers can change the world by providing reliable services and infrastructure that will improve people’s lives.
  • John can be found on Twitter as @JohnChidgey and @PragmaticShow. His podcast is Pragmatic, and his website is Tech Distortion.

Thanks to Daniel Oines for the untitled photo of a crescent wrench. Podcast theme music by Paul Stevenson.

Episode 66 — Nuts and Bolts


NutsAndBoltsWe discuss some of the considerations that go into choosing a threaded fastener in this episode of The Engineering Commons podcast. It can be more complicated than you might think!

  • Carmen has a tendency to make up words every now and then; this leads to quizzical reactions from his co-workers.
  • For many years, Jeff has used the Machinery’s Handbook as his reference for most issues related to threads and threaded fasteners.
  • We let slip a million-dollar idea; a blank book that lights up with content when turned on. How many years until this becomes a reality?
  • The primary reason for using a threaded fastener is to allow for the assembly and disassembly of components.
  • If disassembly is not required, one might be better off by welding, soldering, brazing, riveting, swaging, or casting components together.
  • Common threaded fasteners include bolts, screws, nuts, and studs.
  • Despite the differing definitions about what constitutes a screw and what constitutes a bolt, we go with a distinction in usage: a bolt needs a nut, while a screw does not.
  • When selecting a screw or bolt, one usually starts by looking at the strength needed in two places; the fastener itself, and the threaded connection.
  • Plain washers are used to distribute forces that might deform or mar one of the clamped components.
  • The cylindrical portion of a bolt that extends from the underside of the head to its point or end is called a “shank.”
  • Lead is the linear advance of threaded fastener as it makes one complete rotation about its longitudinal axis. Pitch is the spacing between adjacent threads on a threaded fastener.
  • RightTighty, Lefty Loosy” is a mnemonic device for remembering which way to turn a threaded fastener so as to tighten or loosen the connection.
  • Measuring the diametric distance across the tops (or “crests”) of an external thread reveals the “nominal” or “major” diameter of that thread.
  • A notation of “M10 x 1.5″ designates a thread that has a major diameter of 10 mm, and a lead of 1.5 mm.
  • While metric fasteners identify the lead directly, English threads give the inverse of the lead. Thus, the notation “1/4-20″ indicates a thread having a major diameter of 0.25 inches, and 20 threads per inch (a lead of 0.05 inches).
  • In the United States, the primary thread reference is the Unified Thread Standard.
  • Most of the world uses the ISO standards for thread forms and sizes.
  • When selecting a threaded fastener, it’s good practice to use a coarse pitch unless you have a good reason for not doing so. Fine pitch threads are normally reserved for those cases when vibration might tend to loosen the threaded connection.
  • In the American system, sizes below 1/4 inch are identified by numbers that decrease as the nominal diameter decreases.
  • External threads may be machined or rolled; internal threads on machined parts are typically drilled and tapped.
  • A rule of thumb is that the axial thread engagement should be at least 1x the nominal diameter for steel, 1.5x the nominal diameter for cast iron, brass or bronze, and 2x the nominal diameter for aluminum or zinc.
  • A “blind” tapped hole allows for an internal thread that doesn’t go all the way through a component.
  • Many different head types are available in threaded fasteners.
  • A countersink is a cone shaped hole, while a counterbore is a flat-bottomed hole.
  • Establishing the proper preload is an important part of designing a threaded connection.
  • The bolting process can be modeled as going through the stages of rundown, alignment, elastic clamping, and post-yield.
  • Much of the torque applied during bolt tightening goes to underhead and thread friction, rather than bolt preload.
  • One means for determining proper bolt torque is the turn-of-the-nut method.
  • Jeff’s father taught him the criss-cross method for tightening bolts in a circular pattern.

Thanks to Scott Robinson for use of the photo titled “Jetty Bolts.” Podcast theme music by Paul Stevenson.

Practical insights for the engineering crowd