Why we moved away from drill-specific adapter plates

When we started developing Copilot 1, the plan for mounting it to cordless drills seemed fairly straightforward: design a dedicated adapter plate for each drill model, using the existing screws in the rear housing to secure it.

Each plate would match the shape and screw pattern of a particular drill, giving Copilot a neat, secure mounting point. As we added support for more drills, we would simply add more adapter plates to the range.

That was the idea, anyway.

Not long after the first Copilots shipped, we discovered that a drill’s model number didn’t always tell the whole story.

Same model, different mounting points

We found that drills carrying the same model code could have slightly different rear housings and screw patterns, depending on when they were manufactured. We encountered this with the Milwaukee M12 FPD2, for example, where differences between earlier and later versions meant that an adapter designed for one wouldn’t necessarily fit the other.

For someone using the drill, these changes might go completely unnoticed. But when you’re making an adapter that needs to line up precisely with existing screw holes, even a small change matters.

Suddenly, it wasn’t enough to make one adapter for each model. We potentially needed different adapters for different versions of that model, and customers would need to identify not just which drill they owned, but which revision—or when it was manufactured.

That’s quite a lot of homework just to choose an accessory.

Even covering a small slice of the cordless drill market would mean maintaining an ever-growing collection of adapter plates. Each new model or housing revision could add another variation to design, test, stock and help customers identify.

Why injection moulding changed the equation

For Copilot 1, this was inconvenient, but potentially manageable. Its plastic components were 3D printed, which gave us the flexibility to revise a design and produce small batches without investing in a dedicated mould for every variation.

For Copilot 2, however, we wanted to move to injection-moulded ABS/PC plastic as part of improving the product’s durability, consistency and overall finish.

That changed the economics considerably.

An individual injection-moulding tool can cost us around US$4,000, and getting a part ready for production can take months of sampling, testing and refinement. That’s a worthwhile investment for a component used across a large number of products. It’s much harder to justify for an adapter that only fits one particular version of one drill.

Multiply that across hundreds of potential adapter designs, with more appearing as manufacturers update their tools, and the model-specific approach becomes impractical.

The problem wasn’t just the tooling bill, either. We would still have to manage all those variations, keep the right ones available and make sure customers received the correct plate.

We realised we needed to change the mounting system—not just keep adding to the catalogue.

Designing an adapter around the differences

This became an important part of the Copilot 2 redesign: moving away from fixed, model-specific plates towards an adjustable adapter that could accommodate different rear-housing screw positions.

Rather than making a new plate every time the spacing changed, we could accommodate those differences within the adjustment range of the same adapter design.

That doesn’t mean it fits every drill. Suitable rear-housing screws, their spacing and the surrounding housing shape still matter. But it gives us a much more practical way to support a wider range of drills without needing a separate mould for each one.

It’s one of those changes that might not seem particularly exciting at first glance, but makes a substantial difference to the finished product.

The goal was never to build the world’s largest collection of drill adapter plates. It was to make Copilot easier to fit and use—and that meant designing around the differences between drills, rather than trying to make a separate part for every one of them.