Guitar nut files, spare nuts and saddles or bone upgrades for classical guitar?

I’d like to learn how to lower the action on a classical. I know I can get a luthier to do it but with seven guitars here, the action needing slight lowering on four of them, and my inability to leave this jail cell for a while, I think it would be a good DIY skill to pick up, at least starting with the one guitar the warden lets me have in my cell.

There’s a lot of info online about whether and how to do it (although more advice here is always welcome), but since there’s a chance I’ll mess it up while on the learning curve, I’d like to know a few things: 1) Is there a noun for the “action” of a guitar other than literally ‘string height’? I can easily handle the Chinese for ‘lower the string height’, ‘reduce the saddle height’ and so on but can’t figure out whether there’s a noun like ‘action’. 2) Are there good luthier supply lines here locally like an accurate gauge for string height, or will precise rulers so? (I’ve got a stainless one marked down to the half millimeter which I imagine will do.) Do people turn to online suppliers like Stewmac, and are there more affordable or other sources? Any other good online sources you’d recommend for shipping to Taiwan, probably just a blank nut and saddle or two in case I mess up the original; I might also want to change three guitars’ nuts and saddles to unbleached bone, in which case for the nuts I might pick up a set of luthier’s nut files, although that might be a bit pricey so for new nuts so I might just start with trying a saddle. I might mail have to find a way to get a couple guitars to Taiwan_Luthier. BTW, @Taiwan_Luthiers TL, you’re back in Taipei, right? Still at the bottom of the mountain? What would you charge for installing a bone nut to replace a plastic one and ensuring the action’s low but without fret buzz? And for a saddle, which is easier, what would you charge?

I really doubt it, and they would be really overpriced. Get yourself a set of feeler gauges.


Nearly ever guitar shop in Taipei they know the word “Action”. Even though I speak Chinese they still say “Action” in English. And pretty much all the Luthers at guitar shops speak music related English. But yeah learning to do things by yourself is always good IF you have the time. Changing the action is really easy.

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You can lower the action at the saddle yourself, and possibly adjust the truss rod. However you need nut files to lower the nut action.

The key though is don’t force anything. You can damage the guitar if you force the truss rod for example, causing an expensive repair.

You should start with the nut action. You press down the string at the third fret and there should only be barely enough space between the top of the first fret and the bottom of the string for some light to come through. If you overdo this your guitar will sound like a sitar when the string is open.

Then look at the saddle. You want the action at the 12th fret (with a capo on the first fret, distance between the top of the 12th fret and the bottom of the string) to be about 1/16th" at both E strings.

You also want as little neck relief as you can get away with. Tighten the truss rod until there is barely enough space between the top of the 8th fret and the bottom of the string to see light come through (with a capo on the first and the 12th fret). If you start getting buzzing between the 1st and the 8th fret, you have gone too far and need to back off.

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Here is a good guide. As you have multiple guitars you might as well get a guitar action gauge. I use a ruler but up to you.i only have 3 instrument but soon to be 4 or 5 , so may get one. So out of curiosity which instruments do you have ? Any pics ?

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You can probably print out a setup gauge from the internet.

There are ways to get around a nut file but I find it necessary. The key is that the nut slot bottom must be either flat or rounded. If you end up with a V shaped nut slot then the slot will bind the string causing problems and even string breakage. There is a way of using a wound string as a saw to round the slot but it only works on softer materials like plastic. Bone is quite hard, and it isn’t a material that you can DIY too well without the right tools.

Another challenge is making the nut slot the right spacing and not have it look off.

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Thanks for the link, crusher! That was actually one of the first I read before deciding this was probably something I could tackle, and it’s a good guide. And thanks TL for the details on the various adjustments.

Two capos at the same time? Interesting. I’ll need to pic up another capo.

I may also need to widen the low string’s nut slot for an ukulele when I get the next set of linear tuning nylons for it, as the low string may be too thick for the slot. I won’t know till the strings need changing, though, and I’ve only ever changed them once, in 11-1/2 years. It doesn’t ever go out of tune, either. Weird.

Posters above mentioned feeler gauges, but looking at instructions, it seems all I really need to check the height is either a string action gauge or a precise ruler with markings starting at the edge. I’ve got a stainless ruler with 1/2mm increments that starts at the very end, so I’d think that would do the trick; does it look ok to y’all?
I’ve got a bench vise but might need to pick up a new file for the job, along with the right saddle blanks. I was thinking bone, as it’s supposed to transmit the sound to the top better due to its density and harness or something.

I have pics of some of the guitars, but can’t access the Baby Taylor (1st pic below) or CG101A’s (2nd pic) for a few months, so those are stock photos.
Baby Taylor mahogany dreadnaught That might not need adjustment, but I won’t know till I can pull it out of storage and change to nylon ball-ends.

These two were for my wife and I to learn and relearn, respectively, classical guitar about 13-14 years ago, student-grade, decent but with poor sustain (due laminated spruce tops and generous polyurethane finish). I’ll definitely have to lower the action on one. TL already did the other one for me, years and years ago. CG101A w text These are great budget guitars and really durable, good for a student’s first classical, unless you’re loaded.

BTW, the Cross guitar (folding electro-acoustic) seems to have a thin white strip under the saddle (see tiny white dot on left under saddle; that’s the end of the strip), as if it were removable in case you wanted to lower the action at the saddle a little. Ever heard of that before? It’s in the shop but here’s a collage of it and a zoom in on the bridge. I’ve also asked the maker about it but haven’t gotten a reply yet. It’s got a truss rod, with the plate covering access to it presumably being the black bit screwed to the head above the nut. I’ve never messed with truss rods before.
Saddle strip

This is my nicest, a luthier-made concierto (Mexican luthiers grade their guitars by quality, the top two being conservatory and concert-grade) by Sergio Huerta of San Miguel de Allende. It’s got a bone saddle and nut, and I’ll probably lower the action a bit, later. With velvet gloves.

As for truss rods, There’s one in our Baby Taylor BT2 mahogany steel-strung acoustic (which I’ll be restringing with ball-end nylon) and the folding Cross 2.0 (classical version with nylon; my pics, but none in rest.

This is the Yamaha Guitalele my older son plays. It was a bit boxy sounding at first (laminated top) but is a fun size, and Martin actually plays it well and gets a good tone out of it. And he doesn’t mind the sound at all. I’m the only person in the family who’s not tone deaf. :rofl:

I still need to learn about the role of truss rods in adjusting action but have some good online guides to read next. Here are the two on the sofa that my younger son (7) plays, a Mahalo uke with linear tuning like the first four strings on a guitar, and a toy guitar from Celaya, Guanajuato that is surprisingly playable. Here also is a pic of the uke when my 1st son (now 11) started playing it at age three weeks.

Starting young