tuners for 70s Martin D12-20 12-string

[Tony Lewis Skypilot Guitar Repair]

Thoughts: From the wear marks and the ruler in your photo, it looks like 1″ long posts will engage in the headstock. The Stewmac tuners should work OK. The pull of the string on the post shouldn’t pull any more on that post then on a long post on an un-slotted long peg head so depth of post into headstock for support shouldn’t be a concern. But if you measure the width and are concerned there may be another route to take. I don’t know this but perhaps the golden age tuner pegs are interchangeable between them? There are short and long peg choices for the three peg “prewar” model. It gives the lengths of the long or short pegs. I’m wondering if the longer pegs (they are .60 longer than the 12 string pegs) from the prewar model can interchange with the 12 string model. They look similar. They are the same diameter. Yes, the longer peg is about a 16th shorter but hopefully will still engage in the peg head (you can measure length of true engagement on guitar). From the wear marks and from the ruler in your photo, it looks like the length should work. If the length works, you could call Stewmac and I’m sure they’d see if they interchange.

Note that the string hole is higher on the longer peg then on the 12 string peg and higher then the Martin peg. You can fill the hole and re-drill the hole to center. Also, if there haven’t been extra holes drilled in the headstock and the new tuner mounting holes don’t align with the stock hole pattern on the headstock, you can fill the holes on the tuners and re-drill them to fit instead of peppering the headstock with more holes. You can use the same method to fill the peg holes. You can find an article on easily filling the holes by typing “Golden Age Tuner Hole Relocation” in the “archives” search engine.

[Tony Lewis Skypilot Guitar Repair]

Can only load three pics so here are pics of tuning peg sets for comparison. Looks like you can interchange pegs…..

[Dan Erlewine]

I think Tony is right and that it should work.

[Tony Lewis Skypilot Guitar Repair]

Hi Dan, I may have inquired but can’t remember: Do you think it may be a good idea to have blank options (no mounting holes) of Golden Age Tuner’s? That way the repair person could drill holes to suit the differing patterns of different guitars? In my brief, rookie repair career, almost all older acoustics have had peppered headstocks from tuner change outs.

[Matt Miller New Noise Guitar Repair]

I didn’t see the replies… never got an email alert like I thought I would. ¯\_(ツ)_/¯
Thanks for your input everyone.
I ordered the StewMac GoldenAge tuners. They fit perfectly, even the mounting screw holes matched up! My customer loved ’em!