Calipers, tolerances and the first factory sample

The first parts off the tools are the moment of truth for a product (sample note).

They come to the workshop in a box with a measurement report from the factory. I measure the critical dimensions again, assemble ten sets, look at the colour under daylight and use the product for a week.

Then the factory gets one page: sign-off, or the list of changes with photos and numbers. Most samples need one round of small changes; very few need two.