Nut string binding

[pingu]

hi folks ,

I have moved up a guage to
TI 13 flats ….

i now have a bit of string binding
on my G and B strings whilst tuning

should i open the slots out a bit
with sandpaper ?
how do i ensure that i don’t deepen
the slots whilst i’m widening please ?

[dot75]

Filling the slots with graphite (aka pencil lead) worked for me...
worth trying before taking more drastic & non reversible steps.

[sgosnell]

Nut slots need care and attention to detail. I do it by feel, by doing it very slowly, and a little at a time. If the slots become too deep, some cyanoacrylate or UV resin can fix it, but it's always a pain. Slowly, a little at a time, try and retry, is the only way I know.

[pingu]

i’ll try to be more specific …

how do i widen the the slot
(not deepen the slot ….)

sandpaper ? what grade ?
how should i physically achieve a
good result ….

thanks

[pingu]

Filling the slots with graphite (aka pencil lead) worked for me...
worth trying before taking more drastic & non reversible steps.

thanks but i still need to widen the
slot ….

[sgosnell]

I use a file. Sandpaper can be problematic, because it's so flexible. You need to use something of the proper thickness to wrap the sandpaper around, and that can be difficult to find. You need a thin file, of course, and it helps if the cutting portion is only on one side, and not on the edge. A fingernail file can work. A thin card or something like it, with the sandpaper on only one side can work. I would use rather fine paper, 400 grit or finer. You want the sides to be smooth, not having scratches and grooves.

[dot75]

An old credit card worked for me, 600 grit glued to the sides & none on the base...good luck.

[pingu]

Brilliant , yes thanks guys

[Freeman Keller]

i’ll try to be more specific …

how do i widen the the slot
(not deepen the slot ….)

sandpaper ? what grade ?
how should i physically achieve a
good result ….

thanks

There are lots of ways to Macquiver this including welding tip cleaners, wrapping sand paper around a guitar string and so forth but I use gauged nut files with a rounded cutting edge. I use the next larger file than the diameter of the largest string I will ever use, and I carefully measure both the clearance to the first fret and the "back fret" clearance when fretted at the second. I go slowly, tightening the string and measuring the gaps - it is easy to go too far and then I have to make a new nut. When I'm done I like to polish the nut a bit and glue it very lightly into the slot with a couple of tiny drops of CA.

[nevershouldhavesoldit]

An old credit card worked for me, 600 grit glued to the sides & none on the base...good luck.

Remember that all credit cards are the same thickness (per ISO) - and that thickness is 0.0299”. So you can’t use one on a slot smaller than that plus the thickness of the abrasive paper you stick on the side(s).

There are many ways to shape the slots. I like this one (from lutherie.com), which is based on a bell shape.



Here’s the narrative:

”The nut is in yellow, the fingerboard is dark brown. The string is the green line, and the tuning machines are off to the right somewhere. Notice that the string connects with a smooth curved surface, no corner or edge. Whether the string is coming from the top or the bottom of the string post, it will slide smoothly into the nut slot. The string is in complete contact with the front 30% of the nut. There's plenty of substance there to keep the string from sawing its way deeper into the bone. ”

Here’s the shape from above. I don’t exaggerate the lateral flaring like that. I just put a gently rounded taper on it.

[nevershouldhavesoldit]

I use the next larger file than the diameter of the largest string I will ever use

For most guitars, that's not a good idea for changes of more than 3 or 4 thou. Most luthiers I know seem to consider ideal string clearance in a well shaped slot to be about 2 thou. More than 3 or 4 thou can cause ghost tones, buzzing, and intonation inconsistencies (because the string doesn't have a stable rest position and shifts in the slot, especially if you bend). And the slot depth has to be proper for the size and tension of the string. For example, a fat flatty will vibrate over a narrower path than a thin RW when plucked identically - so you can usually lower the action further for the fat flat than the thinner round without fret buzz.

The string should be gently cradled by at least the front 30% of the entry side wall and bottom of the slot. And the straighter the string's path is into the slot, the more contact and support it should have. This can mean having to cut fresh nuts for changes of more than a few thou, but it's worth it in my opinion if you change gauges that dramatically. You can most often go from 11-52 to 13-56 without a problem. But even going from 10-46 to 13-52 can cause enough problems to make some guitars unplayable without a new nut and fresh setup.

I've had guitars on which a nut was off just enough to cause subjective tonal problems, e.g. a few have sounded more "brittle" for lack of a better term. An unpleasant change in tone can be also caused by ghost tones from a slightly loose slot. The material from which the nut is made affects this, as does the overall construction of the guitar (e.g. string angle from peg to slot, headstock angle, etc).

[sgosnell]

That link is dead, unfortunately. I agree that a credit card is likely to be too thick, but there are other thinner items that can be used. I don't worry about a bell shape, I just angle the slot so that it goes toward the post, I see no need to go both ways, because the post isn't going to move around. But angling it toward the post is important to me, to help prevent binding against the rear of the slot, especially when the peghead is wide.

[nevershouldhavesoldit]

I agree that a credit card is likely to be too thick...That link is dead, unfortunately.

All credit cards are 0.0299" thick - there's no debate because it's a standard set by ISO. Even with abrasive paper only on one side, the thickness will be ~0.032".

The link just worked fine for me. Here's the URL: Nuts - how to cut the slots

[EDIT] OK - I give up. I pasted the URL and it turned into the page title. If that link doesn't work, here's the URL with spaces before and after all the punctuation:

http : // www . lutherie . net / nuts . html

[Lionelsax]

I bought nut files, they are not cheap but they are efficient, if you like your guitar it deserves them.
I put a little bit of valve oil on the nut too.

[sgosnell]

Whether the credit card is too thick depends on the width you need the slot to be. It's certainly too thick for any of the plain strings, and probably for the G, but it might work for the others. And I still get a Not Found error using any of the links you posted. Maybe it's just me, but lutherie.net doesn't seem to exist. I can't get to it even with the basic URL. There is a lutherie.com, but it doesn't seem to have that page. I also tried luthierie.net and .com, without success.

[nevershouldhavesoldit]

Whether the credit card is too thick depends on the width you need the slot to be. It's certainly too thick for any of the plain strings, and probably for the G, but it might work for the others. And I still get a Not Found error using any of the links you posted. Maybe it's just me, but lutherie.net doesn't seem to exist. I can't get to it even with the basic URL. There is a lutherie.com, but it doesn't seem to have that page. I also tried luthierie.net and .com, without success.

I don’t know why you can’t hit it. Here’s a screen shot of the lutherie.net homepage - you can see today’s date and time in the browser header.



and here’s the nut page:

[pingu]

wow making a good nut slot is
quite involved …. in 3 dimensions !

thanks for all the infos everyone

I’ve changed my mind about opening
out the slots !
I think I’ll just go with the graphite for now and see how that works out

thanks again

[sgosnell]

I don't know why, but I consistently get a 404 Not Found error for anything concerning lutherie.net. I turned off all privacy protections, and still get the error. I'm not denying that it exists, just that I can't load it, not with Chrome nor with Firefox, not on computer nor phone.

[dot75]

I don't know why, but I consistently get a 404 Not Found error for anything concerning lutherie.net. I turned off all privacy protections, and still get the error. I'm not denying that it exists, just that I can't load it, not with Chrome nor with Firefox, not on computer nor phone.

Works for me - Firefox Chrome & Opera, haven't tried on a mobile...

Today i learned that special files exist for opening the holes in pearls...

[pingu]

1264635[/URL]]wow making a good nut slot is
quite involved …. in 3 dimensions !

thanks for all the infos everyone

I’ve changed my mind about opening
out the slots !
I think I’ll just go with the graphite for now and see how that works out

thanks again

update , the pencil graphite is working just fine ….
thanks to those that suggested it
(and sorry to doubt you)

[RJVB]

One of the first DIY lutherie tricks I learned from a luthier is that binding and nut-buzz can often be corrected with the string itself. Take it off, or take a fresh or old string of the same gauge and use it as a flexible file. You'll be creating the rounded edge at the front of the nut quite naturally and on the rear you can pull the string towards the corresponding tuner to reduce the exit angle.

Of course this will work better with round-wounds...

And if graphite doesn't do the trick: tune the string to pitch, lift it out of the slot, fill slot with some pure vaseline, put string back.

[sgosnell]

Strings work for smoothing slots. The tools sold for cleaning welding torch tips work the same way. IME a common cause of string binding isn't really the size of the slots, but simple roughness, which catches the windings until they jump over a rough spot. The slots need to be very smooth, and that takes time and attention, which they don't always get enough of.

[darkwaters]

To lubricate the slots, I like to use waxed dental floss. It also cleans the slots and removes any gunk, especially pencil graphite (which I wish I’d never used).

To widen slots, I’ve used sandpaper, carefully, and it seemed to work fine, but I really need to invest in good nut slot files.