So my luthier pulled the neck off of my new-to-me '68 F-112, then called me up and said, "Harry those mini Schaller tuners are too durn' heavy!"
He asked me to find a set that would be both light-weight and good.
Hello Harry,
First of all, the tuners that were on the guitar are not Mini Schallers; they are the first generation Schaller M-6 and they are indeed heavy.
There are a lot of new nice working open-back tuners on the market, but some of them may require filling the old holes in the headstock, which is now drilled for the Schallers and should have 10 mm holes.
Since you are asking for a set that was both light-weight and good you may want to consider the following:
I weighed an original Schaller M-6 unit from that period and it weighed 43 grams; a complete set would be 516 grams.
I did the same with a Schaller Mini tuner and it weighed 32 grams; a complete set would be 384 grams.
I also weighed the Schaller Mini with a pearloid knob, which brought the total weight of a set down to 312 grams.
Now I also weighed an original 6-on-a-plate Japanese import set and the total weighed 288 grams incl. the 12 bushings.
That means that the lightest option (Schaller Mini w. pearloid knob) would only be 24 grams heavier than the original setup. The difference would be less than the weight of a single mini tuner and you would have high quality tuners with only the old screw holes that need to be filled.
Now the only problem might be finding a set of pearloid knobs for the Schaller Mini's. They are available, but you may need to look hard!
The next option I can think of is buying a set of Gotoh mini-machines, which would be in the same ball-park weight wise and they would be a little easier to find with pearloid knobs; probably also a little cheaper than the Schaller Mini tuners.
Does that help you out?
Edit: I understand that you asked for open-back tuners, but I thought this would be the easiest option. If you would think about going for the open-backed Gotoh tuners, as suggested in the earlier posting, you will have a set of tuners that will weigh about 300 grams including the bushings.
Sincerely,
Hans Moust
www.guitarsgalore.nl