How I learned about "Facts Not Opinions" and the remarkable Sir David Kirkaldy

In 2009 doing some random google research I came across a quote "Facts not opinions".

It completely took me down a rabbit hole to discover an incredible story that as an engineer really resonated with me.

I've always held that some of the best engineers I've met, and my favorite whiskey are from Scotland.

And here is proof.

Sir David Kirkaldy does not only fall in the category of "best engineer", but is a true pioneer.

We owe this guy so much, his contribution to engineering extends to an incomprehensible amount.

Let's start with a bit of cosmic history: 

It starts with Iron, the second most abundant metal on the earth's crust, and the stuff that makes our blood red.

Humankind has been using iron for over 3000 years.

First making small trinkets like nails and coins.

To work with Iron, we need a smelter. Anyone that has played Minecraft would be able to tell you so.

Before the 1700, we were using charcoal made from wood in our smelters, so the process was slow and expensive, since wood and charcoal were used for other stuff as well, like building houses and cooking food.

It was in the early 1700s that we started using coal in furnaces, which made producing iron in large quantities more affordable.

This is when we really began using iron as a base for construction materials!

By the mid-1800s we are making all sorts of stuff like railroads, bridges, buildings, Eiffel towers, etc...

Everybody was using it, perhaps bit too much without good quality control.

The problem is, iron by itself, is very ductile. In order to strengthen it, and improve its qualities, like corrosion resistance, one has to mix other elements in like Carbon, Nickle, and other stuff. This is how we make iron based alloys and steels.

There must have been issues with the quality of the iron and the different recipes or alloys. There are many documented failures and disasters, from collapsing structures, sinking ships, to exploding steam locomotives.

That is where our pioneer hero comes in.

David Kirkaldy designed and manufactured all on his own a tensile testing machine.

Pretty much the same machine we see in material labs today.

You can read Kirkaldy's explanation of his machine from his original patent:

Kirkaldy Machine gb186302970a.pdf

Download PDF • 552KB

When metallurgists test materials, they take a sample and intentionally break it.

The reason this is to measure how much it elongated/deformed and the force it took to break.

They've spent years charting, filling tables, and creating beautiful graphs called: Stress Strain Curves.

This curve explains how a material behaves when you pull on it.

Strain can be thought as "elongation", its the deformation from pulling divided by the original length. It's basically the percent of deformation.

Stress is the force per area, and for the ELASTIC REGION, which means exactly that. That the material can return to its original dimension like a rubber band, the relationship between stress and strain is known as Hooke's Law:

σ = E • ε

σ: is the stress (force/area)

E = Young's Modulus (term coined by Thomas Young in 1773)

ε = strain (deformation/original length)

Sir David Kirkaldy, was an inventor, an avid tester of materials and a meticulous (perhaps obsessive) cataloguer of facts. He tested hundreds and hundreds of materials, taking notes and making data tables.

With his machine he started determining the ultimate strength for lots of materials, I suspect anything he could fit in his machine.

So like I mentioned at the very beginning of this post, in 2009 I learned of Sir David and his machine and his building, and the inscription he installed at the main entrance of his test works reads:

"Facts not opinions" -Sir David Kirkaldy

Facts are collected through systematic measurement, observation and verification.

Opinions mostly suck, that is my opinion.

See what I mean!

Opinions are based on personal beliefs and are subjective.

This is why as an engineer, when doing engineering work, I look at the picture of Sir David's doorway which I keep on my desk and remind myself to rely on facts.

For 16 years I longed to visit Sir David's machine and I finally was able to visit. You must book your visit in advance, since the place is maintained and run by exemplary volunteers. You can get the details and plan your visit by following this link:

https://www.testingworks.org.uk/

The building houses not only the legendary machine Kirkaldy built, but other machines that are commonly found on material testing labs. Impact testers, hardness measurement machines, concrete tensile tester, chain link tester, and an awesome collection of artifacts.

This is a picture from his patent, I have filled in some colors so you can recognize its parts with a little more ease.

The main body of the machine is cast as a single piece, some 47 feet long, and manufactured in Leeds which is 300+ kilometers away.

Imagine transporting this, and then fitting it in the building.

This machine is a static professors dream!

Basically the water piston or ram, pushes the carriage, which pulls on the specimen.

The specimen is held by some jaws, which are connected to a horizontal lever arm.

The horizontal lever arm, is connected to the steelyard, which is basically another set of lever arms.

The first feat of this great machine was building it to be robust enough so it could crush or pull specimens with a force of 1,000,000 pounds!!  (454 metric tons).

The second feat was measuring the force exerted by the ram required to break the specimens.

This is where the "steelyard" comes in.

I have to confess, I did not know what a steelyard or heard this term until I was there at the Kirkaldy test works.

I had to look it up, and it's basically the most basic type of scale that uses levers!

Below is a picture of the graduations on the main steelyard beam.

Visiting this place and getting to see this machine in action was a bucket list item for me.

The volunteers ran the tensile tester and tested a piece of wrought iron.

I've sped the test up quite a bit, so you get to see the moment the bar breaks.

The specimen was about 20 inches long, 4 inches wide and 1/8 inches thick.

It took about 20 minutes for the whole procedure.

After this remarkable trip, I was doing research on Kirkaldy and his machine and had another incredible find.

There is a man, Mr. Fletcher, who is both artist and hero. He creates detailed 3D models of historical sites in London using photogrammetry.

And would you believe, he has created a full model of the entire Kirkaldy Testing Works!!!!

We need to be eternally grateful for this man's work.

Mr. Fletcher, on my next visit I will buy you a pint.

This is best viewed on a computer.

And this is the end of what I wanted to share.

If you are an engineer or love metallurgy or history and happen to be in London please visit, please this magnificent place and learn about Sir David Kirkaldy material testing and Facts not Opinions.