I’m a big fan of what Chris Thorpe is doing with The Flexiscale Company; scanning real life rare steam trains and their trucks, and creating scale models of demand through Shapeways.

We has the measure of hearing him talk about it today at Monkigras, and a couple of things in particular stuck with me; a small, yet significant making point, and a more philosophical point.

The small thing first.

Chris talked about something I hadn’t quite clocked about 3D printing before; the ability to reconstruct a 3D scan in any size. This is important because for years people have worried about the ‘tooling costs’ when making things. Sure, you can stamp out thousands of something if you have the right tool, but you’ve got to make sure the tool size is precisely right in the first place.

But with 3D printing, you can print a hundred different sizes, and apart from the cost of the materials, it’s all going to be the same price. No retooling. So you can make one of something work out how it feels in your hands, and decide if it’s right.

That reminds me now of something else Chris said, when holding a 3d printout of a train; “I now know how data feels”.

Now, the philosophical point. Chris showed this:


It’s a part of a train that they 3D printed in stainless steel, on a one-to-one scale, to replace a failing piece. It’s not a new piece, because it has all the same scrapes and scratches in it as the old one. Exactly the same.

Which hurts my head a little, because I start wondering whether it’s ‘the same’ piece in the deepest sense. Because the scratches and scrapes, the places on the part where things happened to it, as still there.

So the action that caused each scratch is still there, represented; it’s not disappeared as it would if you just replaced it with a new piece. If all of the history and patina that surrounds a part is still there, all of that history trapped inside it, is it still actually the same part of the train?

It’s a more modern version of The Ship of Theseus; the ancient Greek question on whether if a ship had all the wooden boards replaced over time, it remained the same boat.

I prefer the Terry Pratchett version, from a book called The Fifth Elephant;

“This, milord, is my family’s axe. We have owned it for almost nine hundred years, see. Of course, sometimes it needed a new blade. And sometimes it has required a new handle, new designs on the metalwork, a little refreshing of the ornamentation . . . but is this not the nine-hundred-year-old axe of my family? And because it has changed gently over time, it is still a pretty good axe, y’know. ”

Except this time, it’s replacing a part with an absolutely identical part, which has been through the same traumas and bashes which have been captured upon it’s surface. The history of the old part has ‘designed’ the new part.

So, actually, is it the same part? I’ll leave you that to ponder.