Changing tuners on Martin D-28

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Changing tuners on Martin D-28

Post by fruitcake »

I need to change the tuners from Schallers to Grovers for a project I am working on. It's a purely cosmetic thing. (Sorry to all guitar purists). I am not a luthier! I noticed that the new tuners don't lay flush with the headstock when placed in:

Image

Is this normal? Will this cause any issues when tensioning the strings? Is there anything I'm obviously overlooking?
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Re: Changing tuners on Martin D-28

Post by Wonks »

The tuners should sit flush to the headstock. It's not good for them to sit like that as string tension will only want to pull the tuner further off vertical.

Can we assume that the Schallers were also a screw-down type with a nut and washer on the face of the headstock, and a single anti-rotation screw, rather than a push-in bushing and the tuner held on with a couple of screws?

If so, the diameter of the 'collar' on the Grovers that fits into the hole may be slightly larger than that of the Schallers. At the moment you don't appear to have fitted the top washer and screw-down nut that will hold the tuner to the headstock. You may find that tightening this down (gently, don't apply too much force) will make everything sit flat.

If that doesn't happen, then you may need to enlarge the hole size slightly. It may simply be that finish has got into the holes at the edges and is making them smaller.

I'd use some callipers (digital or analog) to measure the hole diameters and tuner collar diameters and see by how much they differ (you can also compare the Schaller and Grover collars to see by how much they vary for reference). If not by much, (it may simply be down to the thickness of the plating used) then some sandpaper stuck to a round dowel with double-sided tape could be used to enlarge the hole slightly. Or you could use a hand reamer.

You only really need to make the hole on the rear of the headstock larger, down to the depth the collar fits in, as the top 'nut' diameter is always significantly less.
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Re: Changing tuners on Martin D-28

Post by fruitcake »

Thanks Wonks, I appreciate your your depth of guitar knowledge!

Yes, both the Schallers and the Grovers are screw_down type with the nut and washer. And the Grovers are slightly larger and a little sandpaper was enough to get them to fit.
If I do tighten down the new tuners (I am doing it gently) they will lay flat. Even so, I wanted to be sure I wasn't adversely affecting the headstock once the strings were tensioned. I though better than to enlarge to holes.
Is the best option to enlarge the holes so the tuners lay flat without the nut and washer? Or, is it fine to keep the holes at a snug fit and let the nut and washer cause the tuner to lay flat?
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Re: Changing tuners on Martin D-28

Post by Wonks »

I'd always go for a lay-flat fit where the hole is just big enough. And don't be afraid to tighten the nuts quite tightly, as they do come loose with vibration. You want the tuners locked down to the headstock for best sustain and to avoid any rattles.
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Re: Changing tuners on Martin D-28

Post by fruitcake »

Thank you kindly!! It can be a little nerve racking fiddling on something I haven't attempted before.
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