Shimming a nut

[greekorican]

I attempted cutting my first nut today and after two hours I ****ed up. I carved too deep into the g string slot, and now it buzzes. I have another blank, but I'm wondering if I can salvage this. I'm thinking if I can shim the nut up a tiny bit, i would save myself the trouble of going back and redoing everything. I just can't think of anything small enough to shim it with, except maybe a piece of cardboard. What do you recommend?

[ErebusBass]

You could use a sliver of a business card, or a 3x5 note card.

[greekorican]

Should I put it underneath the entire nut, or just on the treble side? The E string works perfectly, shimming it would mean I would have to file it a bit more.

I'm kinda thinking of just starting over. I was just taking off a little at a time and checking it with the strings on. I also took some measurements with a feeler guage on another bass i have, measuring the height from the fretboard. I guess I should have measured from the first fret. I thought I should take off just a little bit more, and then all of the sudden it buzzed like crazy. I also compared it to another bass I have. I measured .035 above the fretboard with a feeler guage, but at .035 on this bass caused it to buzz. Is there some kind of rule or ballpark estimate I can use to get close to the correct height?

[mongo2]

Originally Posted by greekorican

I attempted cutting my first nut today and after two hours I ****ed up. I carved too deep into the g string slot, and now it buzzes. I have another blank, but I'm wondering if I can salvage this. I'm thinking if I can shim the nut up a tiny bit, i would save myself the trouble of going back and redoing everything. I just can't think of anything small enough to shim it with, except maybe a piece of cardboard. What do you recommend?

I've used baking soda, superglue, and judicious masking to completely or partially fill individual nut slots for recutting.

[LightGroove]

what mongo said...superglue and baking soda...a little goes a looong way and take your time...works really well

[202dy]

Originally Posted by greekorican

Should I put it underneath the entire nut, or just on the treble side? The E string works perfectly, shimming it would mean I would have to file it a bit more.

I'm kinda thinking of just starting over. I was just taking off a little at a time and checking it with the strings on. I also took some measurements with a feeler guage on another bass i have, measuring the height from the fretboard. I guess I should have measured from the first fret. I thought I should take off just a little bit more, and then all of the sudden it buzzed like crazy. I also compared it to another bass I have. I measured .035 above the fretboard with a feeler guage, but at .035 on this bass caused it to buzz. Is there some kind of rule or ballpark estimate I can use to get close to the correct height?

Each instrument is different. Fret height is typically between .025-.045". When using feeler gauges, start with the fret height and add .010" for the G string. Add a couple of thousandths for each string to that. The E string is going to be .016-.020" above fret height. You can refine the feel by cutting the slots deeper from there. Expect to blow it a few times before you get good at it.

Maybe the thing to do is shim the entire nut (no partial shims!) and cut the slots to optimal height for practice. It shouldn't take more than ten or fifteen minutes to do it. Then make a new nut with the data you establish from the first one.

[knuckle_head]

Originally Posted by mongo2

I've used baking soda, superglue, and judicious masking to completely or partially fill individual nut slots for recutting.

Originally Posted by LightGroove

what mongo said...superglue and baking soda...a little goes a looong way and take your time...works really well

This.

[prokfrog]

A shimming technique I picked up from here is to get copy paper, business card, etc., and Krazy glue to the bottom. The paper wicks up the glue, and dries rock hard. Trim around the nut with a razor, run a Sharpie around the edge to blend the color, and you're set. The cool thing is you can repeat the process as many time as you need to get the height you need. Plus you can sand it, or file it down. It worked great for me!

[dmusic148]

Originally Posted by greekorican

Should I put it underneath the entire nut, or just on the treble side? The E string works perfectly, shimming it would mean I would have to file it a bit more.


I also compared it to another bass I have. I measured .035 above the fretboard with a feeler guage, but at .035 on this bass caused it to buzz. Is there some kind of rule or ballpark estimate I can use to get close to the correct height?

Shoulda measured from the fret height, not the fingerboard. The frets between the two basses are obviously different. Shim the whole thing. Sliver of a business card works great.

[Zooberwerx]

Just got done with a similar project on my Kinal 5. I did a quick-fix with the super-glue / baking soda in the slots. Worked okay but the patch density was inconsistent and somewhat softer than the nut material itself. I ended up snagging a small hardwood tile from my wife's art studio and glued it to the nut base. It was a tad too thick so I placed a small piece of emery cloth on my computer table and ran the nut / shim back and forth like an eraser until I reached the desired thickness. I then glued / clamped the nut into place and finish-filed each slot to ~.003-.005 (1st fret gap while fretting at the 3rd).

If you need any of the aforementioned tiles, please let me know. They're strong enough to last but are easily worked with a Dremel tool and sandpaper.

Riis

[greekorican]

Originally Posted by 202dy

Each instrument is different. Fret height is typically between .025-.045". When using feeler gauges, start with the fret height and add .010" for the G string. Add a couple of thousandths for each string to that. The E string is going to be .016-.020" above fret height. You can refine the feel by cutting the slots deeper from there. Expect to blow it a few times before you get good at it.

Maybe the thing to do is shim the entire nut (no partial shims!) and cut the slots to optimal height for practice. It shouldn't take more than ten or fifteen minutes to do it. Then make a new nut with the data you establish from the first one.

I think I'm gonna take your route and shim the nut to get correct data. I just want to make sure I am understanding you correctly. So for example, if my frets are .035", I want there to be .010 between the fret and G string, .013ish for the D, .016ish for the A, and .020ish for the E?

Also, I'm just wondering if I have to curve the bottom of the nut to the radius, or do i leave it flat?

Thanks to everyone who has given me advice so far, I appreciate it.

I just realized something. If I am measuring the distance in between the string and the fret, doesn't the bridge factor in too? How do I remove the bridge from the equation? I thought of maybe fretting the string at the 3rd fret or something like that. What do you recommend?

[gneiss_bass]

Not sure if it helps the OP... but I onced shimmed a nut (from the bottom) with good results by first wrapping it in scotch tape, to work as a form, then scissored the tape down to a lower height that formed a perimeter. I filled the space with JB Weld, which sanded really well. The tape worked great by keeping the appropriate width/length. After the fill hardened, practically all sanding was done for height alone. I ended up sanding most off, because I only needed a few mm. Wordy, but hopefully you can picture it.

[202dy]

Originally Posted by greekorican

I think I'm gonna take your route and shim the nut to get correct data. I just want to make sure I am understanding you correctly. So for example, if my frets are .035", I want there to be .010 between the fret and G string, .013ish for the D, .016ish for the A, and .020ish for the E?

Yes. Remember, you will be measuring from the fingerboard. So the numbers are actually .045", .048", .051", and .055", more or less.

Also, I'm just wondering if I have to curve the bottom of the nut to the radius, or do i leave it flat?

That depends solely on the surface under the nut. If it's curved the bottom of the nut must be curved to fit. If it's flat, then bottom of the nut must be made flat.

Thanks to everyone who has given me advice so far, I appreciate it.

I just realized something. If I am measuring the distance in between the string and the fret, doesn't the bridge factor in too? How do I remove the bridge from the equation? I thought of maybe fretting the string at the 3rd fret or something like that. What do you recommend?

Don't over think it. While it is true that the bridge changes the string height over each fret, the difference at F1 is small enough to leave out of the equation. You are setting the geometry of the neck right now. Worry about the geometry of the instrument when the neck is right.

[greekorican]

Oh, so I should be measuring from the fretboard? I figured I should be measuring from the first fret. Is there any difference?

How should i measure the radius in the nut slot. I'm almost positive its flat, but I would like to know for sure. I don't want to **** up another nut.

[ByF]

I've never heard of a nut with a curved bottom. The new nut should have the same basic shape as the old nut, which I expect is flat on the bottom.

Ed

[202dy]

The fingerboard is the benchmark. It is zero. Fret height is measured from the fingerboard to the top of the fret. All measurements start there.

Use a straight edge to determine if the nut slot is flat. If it is not, it should be the same as the radius of the fingerboard. Radius gauges are available from Stew Mac.

[mongo2]

Originally Posted by ByF

I've never heard of a nut with a curved bottom.

Ever heard of Fender?

They use a curved bottom nut for a curved bottom nut slot.

[John Wentzien]

I use the corner of a dollar bill as a feeler guage.
Fret the string at the 3rd fret. Then measure the gap between the top of the 1st fret and the string.. The paper should slide under with just a little resistance.
I've had good luck with the super-glue for building up the slot..if it's ony one string.
otherwise I'd re-do a new nut or shim the whole thing.

(edit) and re-cut the slots

[greekorican]

could I just file the nut slot flat? I feel like that would make the job alot easier than sanding a radius into it.

[John Wentzien]

Originally Posted by greekorican

could I just file the nut slot flat? I feel like that would make the job alot easier than sanding a radius into it.

As long as there is enough wood so you don't file down into the truss-rod cavity.