Sharp leading edge on bone nut

Rowka

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The leading edge of all 4 string slots on my uke’s bone nut appears to be sharp and “shaves” the strings as they pass through while tuning.

What’s an effective way to ease these edges without detrimentally changing the slot geometry?

FWIW, the strings are Nylaguts.
 
The leading edge of all 4 string slots on my uke’s bone nut appears to be sharp and “shaves” the strings as they pass through while tuning.

What’s an effective way to ease these edges without detrimentally changing the slot geometry?

FWIW, the strings are Nylaguts.

Most of the Ukes that I’ve bought have Aquila nygluts on them, and occasionally I fit that out of choice rather than Martins, but I haven’t notice the same problem as you. It’s important to intonation keep the front edge (ie the one next to the fretboard) of the nut as the strings’ first point of contact. However very (VERY) lightly chamfering that edge with a file is unlikely to upset much and should remove your problem. I am assuming that the string slots are cut to the correct width.
 
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The best way to make a nice slot on nuts is with a fine needle file . The slots are there too keep the strings at there correct spacing and only need to be about half the strings thickness in depth to do the job . If the slot is too deep the strings are liable to become trapped and jam in the slot .
 
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You can get an inexpensive set of perfectly round files that I use for nut slots and though the bridge holes. They are gas burner jet cleaners. Work perfectly and come in many sizes to fit all but the UBass strings.
 
If the slots are otherwise a good size for your string gauges, I would suggest polishing the slots with Mitchell Abrasive Cord. It's what I use after using nut files to smooth over the file marks.

http://www.stewmac.com/Materials_an..._Finishing_Papers/Mitchell_Abrasive_Cord.html

Mitchell_Abrasive_Cord.jpg
 
I second the recommendation for Mitchell's Abrasive Cord. I use it on every new instrument I get. Makes a big difference in how smooth the nut slots are.
 
I would be very careful and find if that is truly the case? Any even small filing will cause the open chords/notes flat in fretboard side. Maybe the nylguts are too thick and slots not wide enough.

Then again if the strings don't travel smoothly by the nut, tuning problems for sure.

I did of what I think a fine job in making my Kala ka-cem ukulele to have a lower action at nut with welding torch tip cleaners, but they are flexible and I was very careful not to file in flat degree, but instead something like 20 one.
 
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I would be very careful and find if that is truly the case? Any even small filing will cause the open chords/notes flat in fretboard side. Maybe the nylguts are too thick and slots not wide enough.

Then again if the strings don't travel smoothly by the nut, tuning problems for sure.

I did of what I think a fine job in making my Kala ka-cem ukulele to have a lower action at nut with welding torch tip cleaners, but they are flexible and I was very careful not to file in flat degree, but instead something like 20 one.

What I referred to as "gas burner jet cleaner" are actually the welding torch tip cleaners as recommended. I put a slip of plastic on the face of the peg head to get the angle right without scratching the peg head.
 
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