Tuner Question

Mandobart

I have an Altamira M20D I bought a few years back right here from Michael. I still love this guitar! My question is about replacement tuning machines.

Nothing wrong with my current OEM tuners. But I'm wondering about interchangeability. In the mandolin world, tuners come 4 on a plate and roller size and spacing have been standardized for decades, so that if I want to replace the worm under tuners on my F5 I know that any mfrs tuners for the same application will fit, though the bushings may not.

On a 6 string slothead GJ guitar is it similar? Are the different mfrs tuners interchangeable? Thanks!

ChrisMartin

Many older GJ guitars have a spacing of 36.5mm between axes, I have a couple of DiMauros like that, one has the common yellow button Delaruelle tuners, the other has what look like covered Selmer style without any markings on the covers. The Delaruelles on my Patenotte are also that size. As far as I can find nobody makes tuners to fit that spacing now, the standard for 3 on a plate is 35mm between centers. No problem for me as I have several old broken sets of Delaruelles I keep for spares but if they do need replacing you have two choices.

I first came across this years ago on an old Favino and and I emailed Jean-Pierre to ask if he knew what tuners his father had used and did he know of any tuners that would fit. After a long wait he eventually replied (I did have the courtesy to write in French) and his recommendation was to get a luthier to plug the holes with dowel and redrill to the 35mm spacing. I got impatient while I was waiting for his reply and bought a set of six Rubners that were separate; not on a plate, so capable of fitting any hole spacing. Either solution will work.

The critical thing with replacing tuners is that the hole size itself can vary anywhere between 6 to 10mm and allowing for years of a metal shaft turning in wood the wear will make for some odd size and shape holes. If the holes are not too oval and you know what size they are; and you are fitting Schaller Deluxe tuners that have the bushings that require a 10mm hole, you could try using a center drill, a 10mm drill with a 6mm pilot that will keep the drill concentric; not every hardware store keeps those but it is not hard to make on a lathe. But the safer bet is to use (or make) a drill jig, I would guess you can get something from a specialist supplier like StewMac or make your own. This will ensure not only the spacing is correct but that the holes are true and in line; any slight deviation will cause the tuners to bind up and feel stiff if not locked solid.

By the way, all of that only applies if you want to apply some sort of engineering principles; many of the early luthiers so revered on here I suspect took a more casual approach. From what I have seen the holes were rarely drilled true and concentric anyway, and appeared to have been whittled and fettled by hand or whatever it took to get those pesky little tuners in there. Of course more modern methods mean everything is far more uniform today.

constantine

Hi Mandobart - I have a great set of Schaller tuners in classified. Some drilling for post width may be required. They are a nice upgrade from the Altamira Deluxe tuners. Thanks - Dean