Dovetail Joint So Tight It Creates Localized Vacuum, Scientists Report

A hand-cut dovetail joint produced by retired cabinetmaker Einar Lindqvist has been measured by researchers at MIT as achieving a fit so precise that it created a localized vacuum between the mating surfaces, rendering the joint effectively permanent without the use of adhesive. 'The clearance between pin and tail is less than 0.002 millimeters,' said Dr. Jennifer Alcott of MIT's Department of Mechanical Engineering, who examined the joint under an electron microscope at Lindqvist's invitation. 'At this tolerance, atmospheric pressure alone holds the joint together with approximately 14.7 pounds per square inch of force. It's a friction fit at the molecular level.' Lindqvist, 74, produced the joint during a demonstration at a woodworking show in Minneapolis using a dozuki saw, two chisels, and what he described as 'fifty years of muscle memory and good eyesight, though the eyesight is debatable at this point.' 'I cut dovetails the way I was taught in 1972,' Lindqvist said. 'Saw to the line, pare to the line, tap together once. If you need a mallet for a second tap, you cut it wrong. If you can pull it apart, you cut it wrong. A proper dovetail should be inseparable, like a marriage but with better tolerances.' Attempts to disassemble the joint for further analysis resulted in the surrounding wood failing before the joint itself yielded — a phenomenon Dr. Alcott described as 'the joinery equivalent of an immovable object.' 'The wood broke. The dovetail didn't,' Alcott confirmed. 'From an engineering standpoint, the joint is stronger than the material. I'm not sure what to do with that information.' Lindqvist expressed mild disappointment that the wood broke, noting that 'the cherry was decent stock' and that 'the joint would have held if the tree had tried harder.'