The Hyperboloid Burr is a six-piece burr puzzle made from identical hyperboloid pieces. It was designed by Oskar van Deventer with the help of Naoaki Takashima.
A wooden version was made as a limited (sold-out) edition for Naoaki Takashima by the Kanagawa Toy Company in Odawara. While working on the wooden pieces, the manager of Kanagawa Toy found an unexpected 7-piece solution. A 3D printed version is also available.
With Oskar's permission, we have recreated the puzzle in Brass. We learned a few things along the way: Brass is heavier than wood. Brass has lower friction than wood. Brass does not flex nearly so much as wood. All this means our puzzle pieces have been machined to very accurate tolerances.
The six piece version of the puzzle assembles and displays well, but if picked up by a single piece falls apart under its own weight. Each piece is 42mm long, has a diameter of 19mm, and weighs 49g. The assembled seven-piece puzzle has a nice heft to it, weighing in at about three-quarters of a pound. T
The seven piece assembly is completed with a satisfying "click" and holds together well - it's a fidgit desk toy in its own right. It turned out the tolerances for this puzzle were absolutely critical. A mere 0.03mm tighter or looser and the seven piece version of the puzzle either does not assemble or falls apart! The pictures contain a slight spoiler, the six piece assembly is shown but can you find the seven piece assembly. The puzzle ships disassembled.