(in the UK) turns out to be a perfect environment for this type of project. They already had a CNC router which can cut the plywood pieces, and there are other members who were willing to help train [Vincent] on the equipment. He found a design on Thingiverse which fit the bill, except for the actual measurements. He needed metric units to match the sheet stock available to him. Once converted he put together a stool that didn’t work at all. The thickness of the plywood just didn’t mesh with the tolerances of the joints. After wandering around to different suppliers in town, digital calipers in hand, he came up with a range of actual thicknesses and adjusted his joint design accordingly.