Nut Slots Cut Too Low

[Jonathan K]

Hello!

I just had a new mandolin set up and it seems one nut slot may have been cut too low. The thing plays great but I get buzzing at the first fret when playing one of the D strings open. No buzzing anywhere else with strings fretted or open.

Is there any remedy for this beyond a whole new nut? I suppose I could raise the bridge slightly but that thought depresses me.

Thanks in advance!

[Fretbear]

A quick and dirty fix is to loosen off the string just enough to get a narrow shard of paper underneath the string. You might have to make a few attempts and position the shim to start a little further back on the nut as the string will want to pull it forward as you tune it up. If it works you will stop the buzz in the short term, and also know that indeed the slot is cut a little too low. You are right, messing with the bridge height is not really the issue.

[Timbofood]

Baking powder and CA glue in the offending slot and refile?
Did you do the set up? If you paid for it, I’d take it back and let the luthier make it right.

[Br1ck]

I use bone filings and CA glue, or whatever the nut is made of. But yes, if you paid someone, take it back.

[gtani7]

That's not a good sign, as far as having a luthier with mandolin experience doing your setup. Get Rob M's setup pdf and some feeler gauges and measure everything else: string height at 1st and 12 frets, relief, check intonation etc, and then go back to the setup person and tell him/her what corrections need done.

https://www.mandolincafe.com/forum/t...by-Rob-Meldrum

[darylcrisp]

Jonathan, if its playing great and only has that one buzz spot, leave it all alone, don't raise the bridge, as fretbear suggested, loosen the one string, cut and put a very small piece of normal paper in that slot(have the paper about halfway in the slot(heading towards the headstock), as you tune it, the paper will move forward fully. Another way is put a larger piece of paper on the slot, tune the string, then carefully use a razor blade to cut the excess paper away. You will barely see it. this will actually be higher than you probably want it(normal paper is around .004" thick). but, this is temporary, it will let you know if that is the culprit, then take it back to the person who did the work and they can easily fill and recut that slot. If the rest of the nut is working great, I wouldn't consider a new nut. The person will only need to remove the strings, use a small file and gently file the nut slightly and that dust will be more than enough, superglue sets it. I've done this to many instruments and none of the repaired area has ever come loose in years.

good luck, let us know how it turns out for you
d

[Wrnchbndr]

First make sure that the nut slot is actually cut too deep. Often debris from the nut file can remain in the slot and make the string misbehave. Sometimes its just a bit of lint from the polishing cloth. Clean the slots with a sharpened wooden toothpick.
Every once in a while I might make a mistake with a nut slot. It happens. Sometimes bone is inconsistent in density/hardness and there may be a soft spot in the material. Sometimes I might get distracted. I don't use the CA/baking soda/bonedust solution. I use one of three solutions. 1. I elevate the entire nut and recut all of the slots. 2. I employ a 4-corner file and cut a vee into the nut and inlay a donor piece of material and recut the slots. 3. I replace the nut.

[pops1]

I would also check that the first fret is not lifting slightly. First I would seat the fret just to make sure. One only side may have lifted.

[Jeff Mando]

My old trick is just use superglue and not much. No baking soda or bone dust needed. Cut a small strip of paper or index card to use as an applicator. Mask off everything else. Just carefully wipe a little glue in the slot, let it dry, and it should raise it slightly. No need to recut, either. If still buzzing, do it again.

I'm sure you have noticed spilled super glue gets hard as a rock. I let it dry overnight before retuning.

[murrayk]

I use the tiniest drop of superglue (just enough to fill the slot) applied with a pin. Works perfectly, you may have to use a nut file to make the groove a bit deeper.

[Verne Andru]

1. I elevate the entire nut and recut all of the slots.

If it's just buzzing on the fret closest to the nut, try filing the fret first. Otherwise pop the nut, slip a piece of index card underneath, reinstall and re-cut the nut slots.

[David Houchens]

I generally cut the offending slot a little deeper and thin a piece of bone to fill the slot. Then reslot to proper depth. This leaves a solid piece of bone in the bottom of the slot. Probably more work than needed but I like all the strings resting on bone.

[Marty Jacobson]

I generally cut the offending slot a little deeper and thin a piece of bone to fill the slot. Then reslot to proper depth. This leaves a solid piece of bone in the bottom of the slot. Probably more work than needed but I like all the strings resting on bone.

Agreed- and the only way to be sure that it's a permanent fix, other than a whole new nut. The super glue in the slot will probably last years if not decades, as well.

Cutting a nut slot properly is inherently a game of chicken. When you take it back, let your repair guy know that you appreciate him going the extra mile to give you actually decent action. Most people just leave it super high at the nut so this doesn't happen. Makes it easy for me to improve a large number of mandolins and guitars out there considerably, so I'm not complaining.
But it may not have been buzzing when he played it - sometimes it takes a bit for things to settle in to where they will be long term.

[Verne Andru]

Cutting a nut slot properly is inherently a game of chicken.

^ this

[EdHanrahan]

... The super glue in the slot will probably last years if not decades, as well.

Not that I'm recommending, but just as an example of what can work:

In the late '80s, when I had little knowledge of repair, I filed a friend's Yahama guitar too low. Having NO idea what a "proper" repair would be o/t replacing the nut, I figured that a paste of superglue mixed with "reconstituted wood shavings" (more commonly known as "paper towel") would fill the slot nicely. It's still going strong 3 decades later.

[Wrnchbndr]

Just adding a couple of comments. Although I don't use superglue to fill a nut slot, but as mentioned by someone else above, I have found that a full overnight curing of superglue seems to result in a much harder result whether you use an accelerator or not. I use a lot of superglue in various ways and often employ an accelerator spray. Google "the glue guy" for my source -- I really like his product line. Fresh superglue is certainly superior.
If I need to elevate a nut (or a bone saddle on a guitar), I'll create a perimeter of masking tape around the base making a sort of tub and use water-thin superglue in very thin multiple applications to build up the thickness. You need to be keep the applications thin or you'll end up with a "wet bubble" of superglue under the hardened surface that doesn't harden. When I achieve the thickness I want, its just a matter of reshaping the base to fit properly.