Nut height

[BJ O'Day]

I'm sorry if this is a dumb question. I've read RM's set up guide and was also directed to another website that discusses the importance of setting the nut slots so the string rests half its diameter into the nut. This is how mine is set up for the G string, but the D, A and E are lower. (the A and E are actually buried in the nut).

Should the height of the nut slope downward toward the treble end? Then the smaller strings wouldn't be set as deep. My mandolin's nut is rectangular. Should it be trapazoidal? I hope I'm describing this so you understand my question.

BJ

[jim simpson]

I usually end up with a bit of a trapezoid shape. I typically adjust the depth to where the strings are the most comfortable to play, then I loosen the strings to expose the top of the re-slotted nut, I then sand the top to minimize the deep slots. I will also re-file the edges so they are not sharp.

[sunburst]

The important things are:
- The string height in the nut is the same as the fret height above the fingerboard (some like them very slightly higher). That gives us comfortable string height without buzzes at the first fret.
- The nut slots are round-bottomed and sized correctly for the strings. That gives us smooth accurate tuning.
- The slots in the nut are roughly half of the angle between the string path over the fingerboard and the string path to the tuner posts where the strings attach. That avoids buzzes in the nut slot at both sides of the nut, and gives us the most durable nut slots. (Since the posts are not directly behind the nut slots, that means the the slots will ideally be slightly diagonal across the nut viewed from above.)

The nut can look much better if the slots are from 1/2 to the full diameter of the strings, all corners are well rounded and smoothed and the nut is finished well. None of that directly affects the performance of the nut or the sound of the instrument, but there are aesthetic considerations in all parts of the mandolin, so the appearance of the nut is as important as we want it to be.

If we cut the nut slots to the correct height and angle as described above, and then remove material from the top of the nut until the slots are half of the string diameters deep (or a little deeper), the shape of the nut will take care of itself.
That's a more complicated way of saying pretty much the same thing Jim Simpson said.

[BJ O'Day]

Jim and John, Thanks for the responses. It cleared things up for me.
BJ

[Wes Brandt]

For me… the smaller diameter unwound ones usually get a slot at least as deep as the string… which could be .011 on a mando… pretty precision work.

[Paul Hostetter]

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



For plain and wound strings.

[Dick Hutchings]

In theory I guess that's ideal but in reality, having the unwound strings a little deeper doesn't seem to hurt. For my mandolin, the extra effort of getting Paul's ideal slot, isn't worth it. I get no buzzing or sticking. But then, my hearing isn't what it used to be so that could be why I don't care to go the extra mile to remove another .005".

[sunburst]

Slots deeper than "ideal" don't really affect the movement or sound of the string. None of the extra nut material is in contact with the string. There is a small amount of extra mass, but it doesn't amount to much. Reducing/removing nut material until we have "ideal" slots is, as I said, mostly an aesthetic consideration. I think it is worth the small amount of extra work to have a smooth, well finished, neat looking nut with strings appearing to lie on the surface rather than looking buried in the surface.
There is a little more nut material sticking up and subject to impact and chipping, so removing the extra material can help prevent that.

[Dick Hutchings]

I'm always afraid I'll take too much from the E string slot. It's not easy to gauge it. At least not for someone that hasn't cut 100's of nuts. I'll try on my next one though since you deem it important to the final appearance, I'll assume others would as well and I don't want my work to appear shabby in any way.

[MysTiK PiKn]

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



For plain and wound strings.

The picture is worth 1000 words.
but
If you prefer 1000 words, Check this:
http://www.lutherie.net/nuts.html

Final finish is personal, and unlimited;
but could include some points mentioned above.

[sunburst]

...since you deem it important to the final appearance, I'll assume others would as well...

A good lesson to learn. I've mentioned it before; someone, somewhere obsesses over each and every detail of an instrument. There are those who examine some specific aspect down to microscopic detail; frets, nut, finish, binding, bridge, glue joints, inlay, etc., etc. while basically ignoring other aspects that may be someone else' obsession. Eventually one of those people will check out our work, and if their pet detail is not up to their standards, they will reject the whole thing as unacceptable.
We cannot satisfy all of those people, but it teaches us to do our best with each aspect of building, even the parts that we don't consider to be of ultimate importance. We have to raise our "good enough" line everywhere so that our work is not unfairly criticized. At the same time, we have to know that someone will notice the details we get right as well as the details we get wrong (some of which comes down to opinion).
We can't let the obsessions of others control us, however. Over the years, I've developed my own standards of what is "good enough", and they're pretty high; above the point of diminishing return for making money at this, and if someone thinks some detail is not good enough by their standards, they need to look elsewhere for an instrument that suits them. We can't be all things to all people.

[Dick Hutchings]

Been to Paul's site many times and I try to achieve his level of work but I simply don't have the hours of experience to just make it happen every time because I read it on his site.

[MysTiK PiKn]

My world is tiny compared to the projects you guys take on. I don't have the tools, I don't have the experience, I don't know how to whatever. I read, I visualize, I read again weeks later, and I slowly get some understanding. It's all amazing and exciting to me. I have been working at improving setup on my mandolin for months. It's getting better; but I can't just leave it alone until I really understand and experience what I believe is possible. It takes not only a lot of my time; it's also an ongoing obsession - to the point where I just want it to stop. Problem is, I keep learning more; and then I have to try that too. And all this time, I know that I am doing work that you guys would do in minutes, or maybe an hour or two. And then Paul or Frank appear here; and it's like God entered the room. And I realize there's a knowledge and understanding that just transcends all the petty things I do for myself, be it ever so great, that's simply just more of the beginner's stages. I just made more changes today. And all this is just a buildup to some major work that's been on the agenda since day 1. Scary part is that that work might be unavoidable; and in this moment, I wonder if it is avoidable, as things get better, or worse, with my latest experiment. It's life in slow motion; and there's some value to it. Likely it takes more time to realize what that really is. So there's more, it seems, always more. I think I just have to love it, and follow it through to wherever it's going. What's really crazy is I now have 4 projects, just because I started one. As for judging someone's work - I am my worst critic. Yes, lots to learn in practice; not just in theory. But I can only start where I am.

[jim simpson]

I find having the right tools (files, etc.) makes all the difference in getting work done. I don' t do work for anyone but myself which reduces any pressure of meeting others expectations. I will help a friend out here and there but no work for hire. I have purchased certain tools mid-project to be able to finish a job. It's also fun to make your own tools/devices in order to not spend buckets of money. To me, hours spent working on projects gives me such a zen like pleasure. It must be cheaper than paying a therapist, lol!

[MysTiK PiKn]

It might be easier, cheaper, faster to pay the therapist and hit the couch for some much needed rest.

[Paul Hostetter]

I'm always afraid I'll take too much from the E string slot. It's not easy to gauge it.

True indeed. Knowing that a string can "saw" its way down lower through actual use, I tend to leave the slots a little bit high at first. If it hasn't lowered itself in a few months, I'll touch it off. Often people make them perfect right from the get-go, then they hear a sizzle a bit later. Better to anticipate that, though there's no assurance you'll get that right every time.

[sunburst]

Part of it is the string straightening out just beyond where it goes over the front edge of the nut, and taking a bend right at the edge of the nut. The string height actually gets slightly lower at the first fret (and other frets) as that happens through playing. That happens whether the nut is new or old. A firm downward push on new strings right next to the nut helps get that process started and gives us a better starting point, but a little extra clearance at the first fret with new strings is always a good idea.

[John Arnold]

As long as the slot is properly shaped, IMHO it makes no functional difference whether the slot is deep in the nut or just half the string diameter. If you prefer the looks, go ahead and trim off the top of the nut. But looks is the only valid reason for doing it.

Should the height of the nut slope downward toward the treble end?

Yes. Even though I am not a stickler for the 'half diameter' rule, I do like for the top of the nut to be roughly the same relationship to the tops of all the strings.
I like to round the backside of the nut, so that the string does not catch on the slot during tuning. In this regard, rounding the edge of the slot also helps. This catching will be most problematical on the smallest wound string, due to the small size of the windings.

Part of it is the string straightening out just beyond where it goes over the front edge of the nut, and taking a bend right at the edge of the nut.

That is why I check the nut height with a straightedge, instead of relying on the string alone. With a thin straightedge in the bottom of the slot and resting against the second fret, there should be minimal clearance over the first fret. If the straightedge rocks on the first fret, it means that the slot is too low.

[Paul Hostetter]

Part of it is the string straightening out just beyond where it goes over the front edge of the nut, and taking a bend right at the edge of the nut. The string height actually gets slightly lower at the first fret (and other frets) as that happens through playing...

If you cut the slot so it simply angles back (more or less in a straight line) toward the tuners from the front edge, you experience the string exiting the slot in an upward arc. This is why I recommend cutting that slot on a curve, such that the string levels gradually toward the front, and doesn't rise:

⟵ click

Cutting them this way also reduces the tendency of the string to "saw" itself lower through use, although a bit of that is inevitable if you use bone or softer for a nut material.

My rationale for "half the diameter" is that the inexperienced person trying to do home setup simply can't see what's going on if the slot is too deep. It's quite true that it shouldn't really matter, but the more excess matter there is, the greater the likelihood of the untrained amateur getting it wrong.

The other aspect of my rationale is that anything above the halfway point does absolutely nothing but constitute unnecessary mass. I've revolutionized playing for veena and sarod players, and lap steel and slide players as well, with the half-diameter approach, as it enables them to gliss directly off the nut. But in the case of mandolins and most fretted instruments, John's point is well taken.

[Wes Brandt]

Very good ideas Paul!

Not horribly long ago realized that using graphite in the slots while doing the final fine filing allows you to see exactly where you are removing material ...or not… as you file, to get the front break angle right and a nice smooth curve … works for me anyway.

...this after using graphite ( various pencil leads) as a lube in the slots for many years

[Mike Conner]

That is why I check the nut height with a straightedge, instead of relying on the string alone. With a thin straightedge in the bottom of the slot and resting against the second fret, there should be minimal clearance over the first fret. If the straightedge rocks on the first fret, it means that the slot is too low.

Ok, so I have done far more than 200 setups over the years, and have always used the string as the gage - tighten, check for clearance, loosen, file, repeat...

I should have thought of this straight edge method years ago! My standard Starrett 6" precision scale would be perfect for this. Thanks John! We can always learn something new...

[Paul Hostetter]

It would take an awfully thin straightedge to fit in a slot for a string narrower than an .014.

[Dick Hutchings]

Hmmm. That's what I was thinking. Maybe a utility razor would span it.

[sunburst]

The boss at the shop where I once worked used a stainless steel 6" ruler, ground thin. I find it simpler to just use a string. We're making a judgement of the clearance over the first fret whether we use a string or a straight edge, and I didn't have any more trouble learning to judge the clearance using a string than using a straight edge.

[Paul Hostetter]

Ultimately what matters is what the string does. We play strings, not straightedges. That said, I do use a thin 6-incher for getting close to the final result when I'm cutting a new nut. In fact, just did it today.