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I’m making a nut for a Les paul from an unbleached bone blank and it’s gone pretty well except (surprisingly to me) for the step when I use my slot cutting saw to start the string slot. the material is obviously pretty hard and chippy. I’ve made three so far and on each one, 5 slots are about perfect but one is slightly off. It’s hard to even tell it’s off until it’s too late.

I’m using my fingers to stabilize the toothed part of the saw on both sides of the slot location to keep it in the right place when I start the cut. But it seems to jump a little as the teeth pull across the bone, just enough to get the location wrong. It’s mainly on the narrower gauge strings where there’s little room for fixing it.

The frustrating part is that they’re looking and feeling really nice leading up to that part, so I’m super happy with the progress in this challenging task. But then to have it fail right there… total bummer.

Am I going too fast? Too much pressure?

Any thoughts or tips are appreciated!

I start the slots on bone nuts with a feather file - it's tapered down to an edge, and very fine which reduces the tendency to move sideways starting a cut.

What kind of a saw blade are you using? Large teeth don't work for this job at all. An Exacto razor saw will work.

_________________
"Act your age, not your shoe size" - Prince

I use a 0.010 stew mac razor saw and make a pull cut. I've shaped the blank but the top has not been polished yet, seems to give the saw a little something to bite into. One light pull and check the slot - if it is at all off I can tip the blade and move it a couple of thousands.

I’m using that same saw. I tried again today by doing my first pull along the corner of the nut where the slot should start and not along the full top face so there was less area. It worked better. Maybe I just need to destroy my first 5-10 before I get a decent one??

Perhaps I should order a few more blanks before I run out

Thanks for the feedback!

Thanks for the feedback!

The next two tries I got the string locations perfect but I made one string too deep and I made one nut too short on the treble side.

Luckily I thought ahead and ordered a 10 pack of blanks from LMI yesterday. I’m not sure I’ll need it because I made a new one (attempt #5 or 6) that seems pretty good. It’s the last in my current batch of blanks so fingers crossed I don’t screw up the install. I guess that’s pretty unlikely though.

I suppose a 15% success rate isn’t too bad for a newbie.

It looks pretty decent actually. Nice and smooth and feels good to the touch. Next thing you know I’ll get cocky and want to replace all my plastic nuts.

As a side note, my wife is getting tired of me talking about by bone and nuts.

Yes start with a nut slotting or similar file as Chris said. We don't use a saw at all in nut making and we make them weekly.

Nut making is an art and Luthiers are actually judged on this when they, we see each other's work. It's been said that it can take 100 nuts until someone gets good, fast, accurate and professional quality with it. Nuts should be minimalistic, have all the physics down (break angle and nut slot shapes), be perfectly spaced, match the fret work (this is huge and very few people even will understand what I mean here) and the nut should be eloquent and made of material that is not chippy or greasy. Nearly as important is the nut channel in the guitar being milled well, uniform end to end, square and the nut at the ends should fit perfectly without one having the ability to catch a fingernail under the transition from nut to neck.

It's not unusual for me to spend ten minutes on the nut channel before I ever go for a nut blank.

At a well known Lutherie school students will spend all morning making a nut and the instructor will come by look at it, say that's nice, throw it in the trash and then tell the student to make another one. Cruel as this may sound the mission is to learn to make nuts as described above but reliably, quickly and consistently too.

The Stew Mac string spacing rulers is excellent and I use mine for not only nuts but for saddle spacing too at times when having to notch Gibson like independent saddles.

It's also one of the most relaxing things I do in the professional Lutherie worlds. I get my favorite drink (not alcoholic), my favorite three files, adjust my chair, light, get out my anvil and start fitting and crafting. I'm kind of slow at it still with a new nut and set-up taking me close to two hours. My business partner can do it in one and a half. But speed is not as important as the idea that your nuts will live long after you Wait, I mean the nut that you make will be an example of your work for decades to come.

Tell me about why you don’t use a saw. I’ve seen several luthier suppliers sell slotting saws and a few folks here using them for just this purpose. So I’m interested to hear why you’re not a fan of this approach.

And if you prefer files, can you provide a link to your preferred type? I suspect, like the other poster, you suggest one that comes to a point on the business end although because I can only see pictures online and can’t really tell in person if the size and shape seems right, it would be great to get a gentle push in the right direction of which one to get.

The follow up question is whether you use the file to start the notch and use another method to cut down for the rest of the slot or if you make the whole cut with a file

I mark my slots with a pencil, then start the slots with my thinnest nut file. Once there's a small slot started I move over to specific gauged files for each slot. I start cutting the slots when the nut is still too high, if it looks like one is slightly off of where I'd like I angle the file and start cutting the slot towards where I'd prefer it to be. Then once I know they are aligned how I want I finish the slots with files to the appropriate depth.

This is how I approached it. I’m interested in hearing if there’s a strategic difference between this and starting with a narrow file. I suspect not really, it’s just what you have or prefer or what works for you. But I’m happy to be corrected.


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Sure - First off we are not hobbyists we own one of the busiest and most successful repair only shops in the country, this country. We also have taught some of the things that I am sharing with you and many here on the OLF have been to our place and our classes. We no longer offer classes and have too many professional musicians to have time to teach.

Saws are OK but too much material is removed for my taste right away. It's not unusual for us to have one shot at a special nut blank such as fossilized ivory from Mammoths that someone paid a pretty penny for so we cannot make mistakes. If someone wants us to touch elephant ivory we deny them service, period..... but that's a different discussion.

A file can score the nut top and then you can examine that score in relation to the nut ends and other slots and get things trued up before removing much in the way of material. What I said is always a good idea in Lutherie by the way to be very sure of what you do before pulling out the tools that things happen fast with. Measure nine times and cut once....

The nut files we use are the Stew Mac gauged files and they are not sharp at one end nor should they be. The bottom of a nut slot should look a lot like the bottom of the strong, curved and the slot should have clearance for the string plus a thou or two on each side AND one common gauge up in strings so if someone wants to go from 12's to 13's it's not a crisis in the set-up of the instrument.

Back to your statement about the file being sharp that is not the goal a nut slot should NOT be a V or anything looking like that. Sure people can get by with this kind of work but it's frowned upon in professional circles. Why? Strings bind in V shaped slots and although the classical, nylon string folks can get away with it when I bend two steps up that binding in a V shaped slot will likely break the string.

I'm a former sailboat racer and we had hardware called jam cleats. A jam cleat is a V shaped nut slot and what results is the sheet (the rope in sailing circles) get jammed in place because of the V shape.... We don't want a sting to do this or it breaks.

So I'm home and off today, holiday weekend but check out annarborguitars.com our shop. Lots of tutorials on the video page and you can see where I work. I have all sizes of the gauged files and use them all too. When I make a nut I use the SM spacing ruler to mark my slot locations and then the .013" nut slot file to score the top of the blank. If I get it wrong I can walk it sideways a bit and I'm only scratching the surface. If I had used a saw and my score would be deeper then if the blank is not high enough I may have just ruined it.... That's why we start with a pencil, then a small file and then we graduate to a file in the appropriate string gauge.

Using the files is an art too. I intentionally scrape the nut slot sides in my efforts to widen slots to again prevent binding. We have a goodly number of professional and famous musician clients who cannot afford to break a string in front of 60,000 people so we have to have it right every time.

My suggestion to you is to pick out the favorite strings that you are using on what you create and purchase the six files for those gauges to start. You can always make a slot bigger but you can't make them smaller so keep this in mind when selecting. If you want I can make a recommendation on files sizes if you give me your string gauges?

For cutting the depth of the slot we use the same files too and it only takes a minute to do. Again you can check progress along the way and favor left or right as needed if your slot is off a bit.

Saws also leave the nut slot bottom more rough and that roughness with something as braiding as a wound sting can sink lower as the loose material wears off and then the slot can be too low at an inopportune time. Nut slot bottoms should be smooth and again no binding.

A few more tips pay attention to the break angle a nut slot should be approx half the head stock set-back angle so say a Martin is 14 degrees make the slots around 7 degrees. Less than 3-4 degrees is too flat and a heavy hitter can get the string vibrating to the point that it breaches the slot and sounds out of tune AND weak.

Lastly for now no one here generally will cut a nut slot low enough. We have a builder guitar in the shop at present to make a new nut. When holding the high e fretted between the 2nd and 3rd on a steel string with a properly adjusted truss rod while that note is held fretted the gap between the bottom of this string and the crown of the first fret should not be more than .0005". That's very low. You may have never played a guitar set-up this way nor had I until I learned about it. It makes huge difference and our clients rave about our nuts seriously often saying things like they can make an F bar chord for the first time ever because the strings are not fighting them.

Each progressively thicker string gets a larger gap to avoid that sitar sound of a low nut slot.

The advantage in cutting nut slots very low is that string stretch is mostly eliminated and so too are the intonation issues that lead many into compensated nuts which are not necessary on a steel string that is properly set-up. Buzz Feitin and Earvanna are bullcrap and poorly thought out fixes for a symptom of another problem and not the root issue of the nut slot not being cut well in the first place.

Hopefully this is useful to you and let me know if you have any questions?

I pretty much make nuts exactly as described by Hesh. I make nuts regularly for everything from mandolins to basses, so I’ve got the full Stewmac set of files, and as many more of various sizes accumulated over the years. But, I’ve made one major change to my technique — I’ve gone back to starting a slot with a 0.010” razor saw. There’s some technique and logic that requires explaining.
I found that when starting a slot with a nut file, there’s a certain amount of wobble and wavering that occurs as you start the slot on the line, and then you’re chasing the line with corrections. After marking the slots with a 0.5mm pencil, I use the razor saw to start the slot with a slow, short PUSH stroke to split the line, leaving a trace of black visible on either side of the line. The saw is very rigid and very sharp, and I just find I can more easily control that first light push stroke very precisely. After I have the start of the slot, I can use a couple of pull strokes to quickly extend that initial slot. From that point, everything is done with appropriate slotting files, which tend to track well the 0.010” saw kerf.
I think it’s somewhat a matter of personal preference of how you achieve the desired result.


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Definitely a personal preference thing and there is nothing wrong with using a saw to start the slots.

What I like about using a file is first I use a .013" for the initial mark because it's thin but thick enough to not flex like the .010" one will. I also use my thumb as a stop so the file goes on the pencil park and my thumb gets parked firmly against one side of the file as a guide. Couple of swipes and a spot check and I'm off to the next mark and slot.

But you're right Tim either tool starts a slot fine I personally would not use a saw beyond scoring the initial slot position and again prefer a file for that too.

Now there is more here too. I've been in arguments here before with people who swear by V shaped slots or who use a saw only or, or, or. My goal is to produce a uniform slot a couple thou wider than the possible string gauges and with a rounded bottom, smooth in the bottom of the slot too with no loose material and at the appropriate set back angle. The SM gauged files are also straight and that aids me in seeing at a glance what my slot angle will be and it discourages the dreaded hump in the center of the slot that is often the cause of the sitar sound that some hear.

When all is said and done there is a lot to be said with consistently using correctly whatever one likes to use that works well and produces a slot like I am describing above.

I've got a half round OOO file that I absolutely adore and it's my favorite tool for nut making and I use it for material removal and refining the shape. It's an example of one developing their personal "kit" for nut making.

One last thing I'm surprised that no one has asked me about my remark above about the nut being appropriate for the fret work?

The intended meaning of this statement is going back to another OLF discussion on fret end bevels. If the instrument has radically beveled fret ends you had better notice this before setting the outer spacing of the nut slots or you may be making the nut twice and have a pissed off client who's strings are being bent off the frets. So be sure to take that into account with the spread of the strings at the nut or it can bite you.

So obvious to me, I assumed all the pros were nodding in agreement.

_________________
"Act your age, not your shoe size" - Prince

Just a semi-pro but Yep.


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Steve Smith
"Music is what feelings sound like"

I’m just a clueless buffoon but I’m guessing you mean you want the fret and nut to match re: their aesthetic

Nut slot location set up according to the usable space on top of the fret which is defined by the angle on the ends of the frets. Of course the depth of the nut slots are also dependent on the fret plane.


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_________________
Steve Smith
"Music is what feelings sound like"

I can see this for a new build. But for a replacement nut, wouldn’t this be pretty rare?

Explain to us why you think it would be "pretty rare"....

_________________
"Act your age, not your shoe size" - Prince

No problem this is a more advanced concept.

We were just discussing, again.... on the OLF fret end bevels and examining why some producers use fairly radical bevels on the fret ends (because they are avoiding semi-skilled labor to shape the ends nicer without eliminating useful fret top surface).

The level of bevel.... is a consideration for the string spacing on the nut. If the bevels remove top surface from the frets they also require the nut to have the strings spaced closer together. Some nut spacing and some bevels will let the string annoyingly slip off the fret top and into the bevel.

We had one in for a new nut because the previous person servicing the guitar didn't even try it out after making the nut and the high e slipped off the fret tops very easily and that's a no go. it was obvious too... I'm known to play very nearly every note on a neck when I'm done with my fret, nut or set-up work.

Because unless I have purchased a really cheap guitar, I’ve never seen an issue where the string slots on the nut are too close to the edge and creating a problem where string roll off was an issue. I assumed, therefore, that generally your goal was to make a nut that closely replicated the original. For example, if I’m replacing my Gibson LP nut, I assume I’d start with Gibson string spacing and edge-to-edge spacing. Unless there’s a “problem” with the frets or if the bridge or a bridge slot is located incorrectly. Or maybe the neck is not straight? But even then, I might be inclined to fix one of those problems instead of making a new problem.

Perhaps I’m not understanding what you’re getting at, though. You may be referring to a more subtle issue.

You stated that you were clueless, but since you obviously understand that the goal is to hew closely to original specs I think you do "get it" , even if your posts don't communicate that.

_________________
"Act your age, not your shoe size" - Prince

Work on enough guitars and you'll find that most guitars, including the expensive ones, have fret/nut/saddle work that can be improved upon.

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Steve Smith
"Music is what feelings sound like"

Indeed. We aim for perfection, but being men - we fall short of our goals.

_________________
"Act your age, not your shoe size" - Prince

My job as a professional luthier is not to identify the perfect nut layout but rather the opportunities to adapt to the needs of my client. Perfection is defined by my client.
Sure, I try to maximize the real estate available on frets by doing good fret work, but the string spacing at both nut and saddle, and particularly string setback from the fingerboard edge, are determined by the player — and players differ … a lot!


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