Feeler Gauges for Setting Nut Slots

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PSmill
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Joined: Sun Sep 09, 2018 12:23 pm
Location: British Columbia, Canada

Feeler Gauges for Setting Nut Slots

Post by PSmill »

Just reviewing this process last week before cutting a new nut, and found the info varying quite a bit, curious for other views? To cut nut slots I start by setting feeler gauges for the height of the 1st fret + 0.018", that seems pretty safe to avoid cutting too deep, and then I lower each string by removing 0.002-0.003 at a time, which can take 2 or 3 iterations. Stewmac suggests starting with fret height + 0.030" (seems really high), and Bill Core says fret height + 0.010 (seems pretty low and risking cutting too deep).

I have been aiming for the action at the 1st fret to be about 0.015 (treble) rising to 0.020 (bass). One source puts Taylor spec. at 0.015 to 0.025 (seems high). I recall Diane saying she could get as low as 0.009".

The nut I just finished the high E is at 0.010", the middle strings in the 0.016" range, and 0.020 for the bass strings. I'm pretty happy with that. No problem for an F barre chord, and no buzzing ever with a heavy pick attack.

Any suggestion to make this process quicker and/or more reliable? Thanks.
tippie53
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Re: Feeler Gauges for Setting Nut Slots

Post by tippie53 »

I have a .009 feeler gauge and I ground a .007 notch in it. the gauge rides the frist 2 frets. I want the .007 notch to go into the fret slot and the should stops..
To make this simple for you , save a .009 string use that as your gauge . with the string under tension if you pluck it that should just clear the string. You can play with the process to get yourself dialed in. I think your on the right track.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
JLT
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Re: Feeler Gauges for Setting Nut Slots

Post by JLT »

I have no real opinion on values for string height, although the ones you gave seem workable as starting points. But this write-up might give you some insight into how to use the feeler-gauge method using a continuity tester:

http://dragonwing.biz/nutcase.htm
tippie53
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Re: Feeler Gauges for Setting Nut Slots

Post by tippie53 »

as a machinist and tool maker there are many ways to maeasure this but in essence
the top if the frets should me about the bottom of the nut slot in a natural or non stressed neck. The most accurate method is this

take the .009 string and you can keep working the slot till you hit that. then you know you have that much till it buzzes.
My issue with feeler gauges is few truly know how to use them. My preference is to use wire pin gauges. you have more accuracy.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
tippie53
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Re: Feeler Gauges for Setting Nut Slots

Post by tippie53 »

https://www.mscdirect.com/product/detai ... lsrc=aw.ds

here is the link for a .006 pin gauge
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
PSmill
Posts: 111
Joined: Sun Sep 09, 2018 12:23 pm
Location: British Columbia, Canada

Re: Feeler Gauges for Setting Nut Slots

Post by PSmill »

Thanks for the link! 0.006" with a 0.0002" tolerance, looks like I'll have add a decimal place to my specs. :)

I'll try the 0.009" string method, although if I understand this is just a measuring tool in this case, and doesn't act as a stop when cutting the slot. Sorry I can't visualize your 0.009" gauge with 0.007" notch method.

Thanks.
tippie53
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Re: Feeler Gauges for Setting Nut Slots

Post by tippie53 »

to help visualize this better
when you make the nut slot. The string when fretted on 3rd fret creates a line you can see from 2nd fret and nut slot. This shows the clearance off the string in relationship to the fret plane. I use my notch gauge and I can see just a tad of clearance off the fret.

As you learn this skill , here is a great exercise for you .
Make a nut , use wood , plastic anything as this is just so you can learn where you can go and the stopping point.

so use a disposable nut. create the slot. Keep going to the point of buzzing. By using the string cut off you know that point. So how much more can you go without buzzing may vary on each guitar. So to get that point as low as possible for that soft touch you can do this and develop your eye to see for your self. Once you do this a few times you will be able to visualize this .

So think of this. The notch on the end of the feeler gauge will allow the end to travel into the slot , but that notch hits the front of the nut. I will get a picture of this on my next set up and we will make a video
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
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