Interchangeable parts

L’exactitude est la politesse des rois

IN THE LATE 18^TH CENTURY, in a small workshop in France, a gunsmith named Honoré Blanc was about to change the world. But hardly anyone noticed.

Blanc was a craftsman, but unlike the others. He saw a paradox: the better the artisan, the more unique the product. A great craftsman produces work that is singular, unrepeatable, irreplaceable. But to Blanc, this created a bottleneck.

Every musket, every flintlock rifle, was a one-of-a-kind creation. If something broke, it had to be sent back to a gunsmith, who would painstakingly refit the damaged part – an expensive, unpredictable process. For a soldier on the battlefield, that uncertainty could be deadly.

Blanc had a simple but different idea. What if all musket parts were identical?

If every trigger, barrel, and lockplate were precisely the same, then a broken musket wouldn’t need a skilled gunsmith to repair it. A soldier could swap in a replacement part, without custom adjustments.

Blanc began making musket components using precise templates and jigs, ensuring that each piece was exactly the same as the next. Then, in 1785, he staged a quiet but extraordinary demonstration for a group of military officials. He took apart a dozen muskets, mixed up the pieces, and, in front of their eyes, reassembled them at random – each part fitting perfectly into another.

The officials were stunned.

If this system could be scaled, they realised, it would revolutionise warfare. Weapons could be mass-produced, repaired instantly and deployed at unprecedented scale. The implications were huge.

One of the witnesses to this quiet act of revolution was Thomas Jefferson, then the American ambassador to France. He saw what Blanc was doing and was so impressed that he wrote home to the United States, calling Blanc’s method a “revolution in the art of manufacturing”.

But then… nothing happened.

The French military, bound by tradition, ignored Blanc’s breakthrough. The guilds—powerful associations of skilled craftsmen- rejected the idea outright. The very people who stood to gain the most from interchangeable parts were also the most threatened by them. His idea faded into obscurity.

And yet, on the other side of the Atlantic, a struggling inventor named Eli Whitney took that same idea and made history.

The Power of Interchangeability

Whitney, best known for inventing the cotton gin, was facing financial ruin when the U.S. government approached him with a proposal. The military needed 10,000 muskets, and fast. Whitney made a bold claim that he could build them using a revolutionary new process – one based on interchangeable parts.

However there was a minor stumbling block – Whitney didn’t actually know, technically, how to do it. What did he however understand was just as important: sometimes, the idea of an innovation is as powerful as the reality. And so, in 1801, he staged a demonstration, one suspiciously like Blanc had performed years earlier in France. He laid out musket components, picked them up at random, and snapped them together seamlessly.

The officials watching were astonished. Here was the future of manufacturing. They awarded him a massive government contract on the spot.

While it would take years for Whitney to perfect the process, the idea had took hold rapidly. Interchangeable parts became the foundation for mass production – the reason why sewing machines, bicycles and eventually cars could be built at scale.

Plus ça change, plus c’est la même chose

Fast forward two centuries and the relevance of interchangeability to construction remains a point of debate. Many projects remain bespoke by default rather than bespoke by choice. Concepts of mass-customisation attract negative stigma. Competing product providers advance their own uniqueness to secure competitive advantage.

And yet, when reviewed technically, many manufacturers share more in common than they typically acknowledge. In developing a kit of parts for MHCLG, we were able to establish how many systems share consistent principles, supply chains and even details.

Just like in the time of Honoré Blanc, alignment of components is less a technological problem and more a cultural one but one that significantly hinders sector wide progress.

As companies individually develop solutions to gain competitive advantage, this collectively creates market fragmentation, which in turn increases costs and presents a heightened risk to clients. While rational at a company level, the drive for individual survival ironically creates suboptimal outcomes for the sector – a market failure that requires coordinated action to overcome.

Instead, the opportunity to digitise, harmonise and rationalise solutions to support interchangeability offers several strategic advantages:

• Reduced Client Risk: Incorporating interchangeability into kits of parts, through standardisation of geometry and performance criteria, would play a vital role in reducing client risk and creating aggregated demand that supports a steady pipeline.
• Protection Against Manufacturer Insolvency: Like replacement parts on the battlefield, interchangeability would provide a safeguard against the risk of supply chain insolvency by facilitating swift product replacement.
• Open Supply Chain Benefits: Interchangeability  could underpin an open access supply chain with multiple suppliers for similar components, minimising risk while delivering economies of scale across the industry.
• Focused Innovation: Interchangeability could support innovation to focus on materials and resource efficiencies within a set of interoperability rules, enabling unique selling points and fostering sensible competition in areas where differentiation provides genuine value.

Just as the French guild system resisted interchangeable musket parts, the fragmented supply chain of today’s construction industry continues to develop custom solutions and proprietary systems that nudge forward industry advancement incrementally but not to the extent it could.

Those however who recognise where standardisation creates efficiency – and where differentiation truly matters – are the ones who are really shaping the industry’s future.

And for that, they deserve a salute ….with both barrels.