Forks are used to tune musical instruments as well as for medical and sound therapy purposes.

Sound therapy is a simple concept. Some practitioners suggest that specific vibrations applied to the body can ease tension, improve sleep, and calm the nervous system. All you need is a tuning fork.

[Willem Koopman aka Secretbatcave] was looking at a master clock he has in his collection which was quite a noisy device, but wanted to use the matching solenoid slave clock mechanism he had to hand.