this is a Viennese style doublebass tuner,made in the traditional way by forging and filing,almost no machines involved.
This tuner is a copy of an old extant model.
Istalled on a Preyer double bass
this is a german model,mixed with british style, Baker
here with handmade screws of wrought iron
milling of the teeth
You can see some pictures of the casting process and also of the making of a rieger copy in the page projects