Tuning Forks
From Atlantic Roleplay Wiki
Title: Tuning Forks
Author: Gregory Ironhand
A tuning fork, by definition, is a pronged device which produces a single, pure note of fixed pitch. This can be used for tuning musical instruments, training voices, or as a standard. A tuning fork that produces "rich overtones" is not a tuning form. It is a musical instrument.
Iron tuning forms normally produce a reasonable pitch without overtones for a short period without maintenance. However, using colored ingots seems to be best. They require less maintenance, and can be very precise for many years without so much as a wipe of oil cloth.