Post to Post Spacing
Schaller, Gotoh and Grover tuners have a post to post spacing of 29/32",
they will not work with earlier Gibson's we are often trying to replace.
When dealing with vintage instruments it is highly advisable to seek a retrofitting replacement so that no changes are made... if possible. This is not possible for for all Vintage Mandolins however as shaft (tuner to tuner) spacing has changed. In some cases there are absolutely no new replacements available that I would deem an acceptable match. When that is the case the best choice is to contact Vintage Mandolin dealers in hopes of finding an original set. But that task alone can be daunting as they are often difficult to locate, expense and of course they too are as old as what you are replacing and may show a good bit of wear.
On these early style Gibson mandolin tuners the round gear sat above the worm gear and tuning shaft (see picture), this was later reversed. After decades of tension and good ole wear and tear the strings tension can often "tilt" the string post towards the fingerboard thereby slightly separating the round and worm gear. Poor coupling of these two gears can make tuning difficult.
When the design was later reversed string tension on the tuning post actually drew the round and worm gear together.
Replacing the Tuners Buttons- On some tuners it is possible to replace just the plastic tuning knob should it crack or break. Some tuners suffer from what is often referred to as "shrunken heads", this condition is the result of the celluloid buttons shrinking to half of their original size. Replacement options are limited (but growing).
