Review on 🧩 Wood Trick Wooden 3-D Puzzles for Adults - Engaging and Challenging Brain Teasers by Justin Herman

My 12 year old son is smarter than a bunch of PhDs I think. He built it almost single-handedly in two assembly sessions. The kit is well constructed and the instructions are clear. We didn't put enough time and effort into polishing and waxing the gears and moving parts, we ended up partially disassembling the crank and wheel assembly to allow it to spin freely. Even in this case, turning the handle is difficult, moderate string tension blocks the entire mechanism. The crank wobbles a lot. If it persists, this model will produce sound, but it's not really a musical instrument. I will try to build Nerdy Gurdy. Search for it on Thingyverse.