It's assumed that just because modern machines use lasers and other electronic technologies, they're far more precise and accurate than mechanical contraptions from many years ago. But as Dirty Jobs' Mike Rowe discovered at a tannery, that's not always the case.

To accurately measure the surface area of a hide with a completely irregular shape—presumably so they can accurately price them—the staff at the tannery use an almost medieval-looking piece of machinery called a Mechanical Surface Integrator. As the hide is fed through the machine, it turns a set of gears and ratchets wherever it makes contact with a series of teeth. And once it passes all the way through, a final measurement is displayed on a dial that's shockingly consistent no matter how the piece is fed through. Amazing. [YouTube via BoingBoing]