Sizing mechanical rings requires a different approach than purchasing plain bands. A standard ring sizing and fit guide measures the inner circumference of a uniform metal loop. However, secret compartment and spinner rings feature thicker shanks and top-heavy bezels that alter how the piece rests against the finger.
When buying a wide-band spinner (6mm or wider), order a half-size up. The wider surface area creates friction against the skin, making your usual size feel uncomfortably tight. For top-heavy secret compartment rings, stick strictly to your exact ring size or consider a snug fit. If the band is loose, the weight of the hinged locket pulls the face downward, leaving the ornament facing your palm throughout the day.
Measure your knuckle as well as your finger base. Because moving jewelry cannot be resized easily by traditional bench jewelers without destroying the internal mechanisms, an inaccurate initial measurement results in a permanent return or costly replacement.
