CertifiedExpert on Instagram: "This metal demonstration shows an incredible concept called “zero tolerance” engineering. The metal piece is precision-machined along a line so perfectly that when it’s split by hand and pressed back together, the edges appear to disappear. It’s not magic or self-healing — the secret lies in extreme manufacturing precision and sometimes slightly malleable metal or hidden magnets that help the halves align flawlessly. “Zero tolerance” here means the gap between the