Idea: drilling string slots in a nut

[Fatcat211]

The bassist in my band broke the nut on his old music man stingray bass. I offered to help replace the nut. Now usually I’d grab a tusq pre shaped and tune it up for optimal fit and playing. However there doesn’t seem to be a near fit for this bass. He had some brass stock and asked me to use that. I cringed.
I’ve made brass nuts before but my finger didn’t enjoy it. I do not have dedicated nut files and use jewelers files, old strings with sandpaper and torch tip files. Ok for guitar, but bass?

So I had this idea of using the old nut for measurments, plotting it out on the new one. Then, I would move to the drill press and drill the string slots in their corresponding sizes. Next I would do the final shaping, which include a radiused bottom (man I hate those) lastly I would angle the slots toward the tuners.

I haven’t done it yet, it just came to mind. Anyone try this before?

 

[beanluc]

Just say no?

 

[guitarbuilder]

The bassist in my band broke the nut on his old music man stingray bass. I offered to help replace the nut. Now usually I’d grab a tusq pre shaped and tune it up for optimal fit and playing. However there doesn’t seem to be a near fit for this bass. He had some brass stock and asked me to use that. I cringed.
I’ve made brass nuts before but my finger didn’t enjoy it. I do not have dedicated nut files and use jewelers files, old strings with sandpaper and torch tip files. Ok for guitar, but bass?

So I had this idea of using the old nut for measurments, plotting it out on the new one. Then, I would move to the drill press and drill the string slots in their corresponding sizes. Next I would do the final shaping, which include a radiused bottom (man I hate those) lastly I would angle the slots toward the tuners.

I haven’t done it yet, it just came to mind. Anyone try this before?

No, but I've often thought that one could cnc rout a nut. I will try that some time in the future... It would be the same idea as drilling, but using a smaller bit to machine away the nut material.

 

[Peegoo]

I suppose you could do it, but dialing in the nut action for optimum comfort and intonation requires removal of material in very small increments. That's why files are the preferred method. A drill does not cut accurately with its side flutes.

If I had to make a nut for a bass and I had no nut files: I would shape the blank and establish the string slots using a small triangle file, and then round out the V-shaped slots using various grits of abrasive paper wrapped over appropriate-sized drills. The larger string diameters on a bass allow this; on a guitar, nope.

Remember that wrapping sandpaper around a drill increases the diameter, so plan accordingly so you don't make the string slots too big for the strings.

 

[WingedWords]

Oh this brought back some memories!

My old dad (a skilled engineer and definitely not a musician) had the same idea when I was making a bass about 30 years ago and we tried it in his well equipped engineering workshop, using a milling machine with an x-y table that you could set to 1/1000" and a set of drills in 1/10mm increments. He did the work (under my guidance) so it was all accurately done. We started with well oversize 3mm brass for ease of holding, marked out the holes trying to match the fingerboard radius and drilled them to match the string gauges and shaped the nut around them.

We spent a long fun day on several attempts. The best we could do wasted a lot of material, and still needed as much adjustment as a standard pre-slotted nut. Later, having got his head round the various requirements of a nut and how to set up string heights and action, he made me a beautiful brass nut by hand, fitted it and set the bass up just right, all in about 30 mins. He's been gone 20 years now and sadly never got to play with CNC, but I'm sure would have taken to it like a duck to water.

Oh, just to complete the story, I didn't much like the sound of the brass nut and replaced it with bone.

 

[E-miel]

That's a nice story @WingedWords.

 

[Telenator]

Interesting idea.
Personally, I would take a piece of brass much thicker than what will be my finished piece, clamp it in a vise at an angle very close to the string break-over angle, and then drill 4 holes, each one the size of the string gauge that will rest in it. Once that's done, I would mill, grind, or saw the top half down to a point where the drill holes become slots. Use files for fine tuning the depth and shape.

I never thought to do it this way, but it's actually quite a good idea.

 

[WingedWords]

That's a nice story @WingedWords.

Many happy memories of working with my dad over 50+ years!
Here he is with his Boxford 5" lathe

And this is the bass, with my son. It was an ash/maple/ebony copy of a Modulus Flea bass. He's a big RHCP fan, but after we made the bass he took up the drums and probably hasn't touched a string since. I must ask him where the bass is now.

 

[GunsOfBrixton]

No, but I've often thought that one could cnc rout a nut. I will try that some time in the future... It would be the same idea as drilling, but using a smaller bit to machine away the nut material.

Like this? saw This on the Fusion 360 Luthier group

https://www.facebook.com/groups/Fusion360Luthiers/permalink/1128288957614174/

Sorry, you might not be able to see it if you aren't in the group. I will see if I can upload it.
Couldn't copy the video but here is an image.

 

[guitarbuilder]

Like this? saw This on the Fusion 360 Luthier group

https://www.facebook.com/groups/Fusion360Luthiers/permalink/1128288957614174/

Sorry, you might not be able to see it if you aren't in the group. I will see if I can upload it.
Couldn't copy the video but here is an image.

View attachment 808334

Yep...just like that...LOL.

 

[Freeman Keller]

Its my understanding that Taylor does cnc their nuts and saddles - that is one of the reasons they use Tusq (they can also mold it to rough shape)

 

[pavel]

+1 on what Peegoo suggests. Unlike for guitar nuts, where I use nice nut files, for bass nuts I've always just used a common round needle file, because the slots are that much wider.

 

[Informal]

I haven't looked into them for years now.. But I'm surprised they don't 3D print them now.

Maybe the material isn't there yet?

 

[old wrench]

Brass is pretty easy to work with simple hand tools.

I wouldn't mess around trying to drill holes. A wasted step .

If I didn't have anything better to use, I'd hacksaw the nut as close to the finished size as I could, and then file or flat sand it to finished size.

I wouldn't cut it oversize - that just means you've got to cut it again. Cut it just big enough so you can file or sand out the saw marks.

At some point you need to mark the string height, might as well do it now by sticking the nut in it's slot, and then mark the approximate string bottom by working off the plane of the fret tops.

Lay out your string slots accurately and then scribe them into the top with a sharp utility knife.

I have thin blades for what jewelers call a "fret saw", but woodworkers will call a "coping saw". That's what I'd use to cut the string path to very close to the finished depth. Wood blades will cut brass OK, they just won't stay sharp quite as long as if they were cutting wood.

You might be able to use a hacksaw to cut your slots, if the blade cuts a narrow enough kerf.

From there it's file work, pretty much like any nut.

If you keep your file clean, it will cut better and leave a smoother surface. Soft metals like brass will sometimes load up a file by sticking in between the teeth. You can remove that junk with either a wire brush or push it out with a scribe that's sharpened to a needle point


Follow up by sanding with progressively finer sandpaper till you hit about 1000 - 1500 grit, and then polish it up nice and pretty.

Now you need to dial the nut in, put it in place and string up to pitch and fine tune the nut for optimal action. If needed, pull the nut and clean it up and re-polish.

A properly fitted nut will stay in place just by friction, you really want full contact - if you use any glue, keep it to a minimum. A very scant drop is all that's needed. You never know, you might be called on to work on the nut again .


Last step is to watch your bass player's face when he plays the bass for the first time with the new nut, and listen to him if he has something to say. Kind words are always welcome, but well meaning, constructive criticism is a useful tool if we pay attention .

.

 

[old wrench]

Many happy memories of working with my dad over 50+ years!
Here he is with his Boxford 5" lathe View attachment 808321

And this is the bass, with my son. It was an ash/maple/ebony copy of a Modulus Flea bass. He's a big RHCP fan, but after we made the bass he took up the drums and probably hasn't touched a string since. I must ask him where the bass is now.

View attachment 808322

Nice story and a nice lathe!

I'm not familiar with Boxford, but it looks very capable, with easy thread cutting ability and all .



edit- There is a good message in post#5. Winged Word's Dad, with a machine shop at his disposal and the knowledge of how to use the machines, ended up making the brass nut by hand and quickly as well.

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[Peegoo]

Most makers that incorporate the PLEK into their production install pre-slotted nuts in their guitars and let the PLEK do the tweaking of the nut slots. It is a high-precision CNC machine.

The reality of the PLEK is that it's no better than what a good guitar tech can do. It relies heavily on the guitar being correctly set up in the machine, and if it's done wrong, the results will be less than optimal. It also relies on a human to crank the truss rod when necessary.

The reason PLEKs are used is they're a whole lot faster than a human, and time is money--especially when it comes to handwork like frets and nuts.

 

[Peegoo]

If you keep your file clean, it will cut better and leave a smoother surface. Soft metals like brass will sometimes load up a file by sticking in between the teeth. You can remove that junk with either a wire brush or push it out with a scribe that's sharpened to a needle point

When working hard and soft/gummy metals, I use an ancient gunsmith's trick to keep smooth files from loading up and scoring the work.

It's so stupid simple it's genius: rub the surface of the file with plain ol' chalkboard chalk. Also, keep a file card on hand as you work, and swipe the file over it in the direction of the teeth on the file. Rub the file with chalk again and continue.

With a good file, this method will create a mirror-like surface on just about any metal.

 

[old wrench]

When working hard and soft/gummy metals, I use an ancient gunsmith's trick to keep smooth files from loading up and scoring the work.

It's so stupid simple it's genius: rub the surface of the file with plain ol' chalkboard chalk. Also, keep a file card on hand as you work, and swipe the file over it in the direction of the teeth on the file. Rub the file with chalk again and continue.

With a good file, this method will create a mirror-like surface on just about any metal.

Yes!

A file card is a lot more than a 3" X 5" piece of paper .

Another tool that properly used will give you the most out of your files.

Chalk works great, too.


edit: Files are very under-rated tools.

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[jvin248]

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+1 Drilling will be problematic... drill bits wander.



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[schmee]

The bassist in my band broke the nut on his old music man stingray bass. I offered to help replace the nut. Now usually I’d grab a tusq pre shaped and tune it up for optimal fit and playing. However there doesn’t seem to be a near fit for this bass. He had some brass stock and asked me to use that. I cringed.
I’ve made brass nuts before but my finger didn’t enjoy it. I do not have dedicated nut files and use jewelers files, old strings with sandpaper and torch tip files. Ok for guitar, but bass?

So I had this idea of using the old nut for measurments, plotting it out on the new one. Then, I would move to the drill press and drill the string slots in their corresponding sizes. Next I would do the final shaping, which include a radiused bottom (man I hate those) lastly I would angle the slots toward the tuners.

I haven’t done it yet, it just came to mind. Anyone try this before?

I've thought of doing it for a guitar nut. But I say for a bass in brass it's very doable. Even cooler if you can angle the drill so there is fall away in the groove toward the headstock!