3D Printing a nut

MuseChaser

MuseChaser

Sep 17, 2023
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Univ of Southern North Dakota at Hoopla
#1
There was a thread about this back in 2012, but things have changed.. :)

I had done some filing on the nut of a Ibanez SRH500F in order to get it to accept the thickness of Roto88s, but I didn't like the strings and now the nut slots really aren't sized properly for anything else. I also have a Creality Enders 3 printer that my son got me almost a year ago that I finally setup a few days ago. I've done a few test prints and the thing is pretty amazing, and not too steep of a learning curve so far, at least in terms of finding other people's designs and printing them.

I have some more PLA filament on the way, and also some PETG, which I gather is supposed to have the strength and durability of ABS (almost) along with the printing ease (almost) of PLA.

After looking at some of the bass nut designs that are on Thingiverse and elsewhere, I didn't see any that were blanks; all had the slots already baked into the design. Most were kind of raw-looking, which would be fine.. I can always shape by hand after the printing is done. Just not too keen on one-size-fits-all slots. I don't have ANY experience using CAD programs, but I supposed designing a bass nut would be pretty easy place to start learning.

Anyone done this successfully and have some tips? PLA or PETG? Any good designs already out there? Any advice on getting started creating one's own designs ... TinkerCad (not wild about the cloud-based need-an-account-crap)? Fusion360 (Too steep of a learning curve?)? Am I in over my head? Bad idea in the first place?
 
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#2
I'm not wild about the cloud stuff either. Other than file sharing across devices I see no need for it, and don't want the added risk either. Can't you modify the designs? Make the existing slots shallowerand narrower, but giving you a starting point for the fit? If it's a PDF there are programs out there that will allow you to edit the file.
 
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#4
RSBBass said:
If you have nut files, It may be easier to just buy a blank and make your own. By the time you program, do test prints, re-program, etc., it probably will be faster and cheaper to just start from a blank.
Click to expand...
You're undoubtedly correct. Except.... I have this printer in my house NOW, I want to learn to get the most out of it, and I don't have a nut blank NOW.....:roflmao:;)
 
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#6
bdplaid said:
Is the material hard enough?
Click to expand...
Well, it's got to be at least as hard as whatever the wood was that Ibanez used on the nut of my SRH500F. It filed like balsa wood. OK... an exaggeration, but nowhere NEAR what I'm used to, based upon the ebony nuts I've worked with on violins and celli.

I've printed a few small doodads out of the stock PLA filament that came with the printer (a very loud emergency whistle, and the obligatory articulated cell phone stand), and I am surprised at just how hard this stuff is... and PLA is softer than PETG or ABS... so I think it'd work. If not, I'm out nothing other than the time it took to experiment. Watched a couple tutorials for Fusion360 and it doesn't look too awful to learn, especially for a small single piece like a nut.
 
#7
PLA is pretty soft in general, though there are harder formulations. PETG a better choice. It's going to be about as hard as the threads at the top of a water bottle. (Those are similar PET. PETG is easier to print.) PLA also melts at low temps, so anything that could be in the sun or in a car shouldn't use PLA.

Be sure to set the print to 100% fill--don't want to have interior voids that are exposed by the nut file.

I haven't been printing for the last few years, but always used Fusion 360 to design things. Steep learning, but powerful. I think I could build a custom nut from scratch in maybe 10 minutes or less. Rounded corners and all.

All in all, I think @RSBBass is right--you're going to be happier in the long run with a TUSQ nut.
 
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#8
Following up ...

Was planning on using Fusion360, but that requires one to sign up for an account. Found FreeCad, which is honest to goodness open source software, and installed that instead. Found some good tutorials, and while it ain't the most intuitive thing I've ever done, learning the basics so far isn't awful. Easily designed a basic rectangle blank, saved it as an .stl, then opened it with a slicer program, sliced it, and saved it as a printable file successfully....just didn't print it.

I'm going to try including the notches, and rounding the side edges. The filets are easy, but the notches stumped me today. Tomorrow's another day.
 
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#10
In Fusion, you’d either draw the nut as a flat shape with the notches already included, then extrude the shape front to back. Or, you could create the notches as secondary tool bodies and use them as cutting tools on the primary body.

I don’t know FreeCAD, but probably one of those would work there.
 
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#11
Getting there! I drew the profile of the nut, including the notches (done with the circle tool, then trimming and re-constraining... the re-constraining took a while to figure out... VERY new at this), then extruded it to a 3D object. Also found that it's VERY easy to go back in and readjust measurements in the 2D sketch (once all constrained) and have those adjustments flow immediately to the 3D part. VERY cool.

Anyway, here's the first test print. I messed up the height.... needed 9mm, which I though I had entered, but I had the height and depth both at 5mm. The notches are way too small, but that was by design... better to have to remove more with a file than have them too big. Also printed it at 20% fill w/ PLA just for the test. Currently printing one 9mm tall w/ bigger notches and 80% fill, still w/ PLA. If this goes well, then I'll switch over to PETG.

nutpic.jpg
 
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#13
Hmmm... after holding it up to the original nut, still on the bass, a couple more questions/observations....

The good news? Overall width, height, depth, and notch spacing are very good! Notches are still a little small, but that's an easy tweak.

The potentially not so good news... now that I'm comparing and looking for details more closely, I see that the original nut's profile, when viewed from the side, is actually pretty complex; it's not a rectangle. The front face, towards the fingerboard, is pretty much vertical, but the rear face of the nut, facing the tuners, is angled, so that the side view is more like a trapezoid. The top face, in which the notches are cut, is also angled back a tad, as are the notches themselves. I'm aware that the slots/notches should do that, but didn't notice the angled back face.

As a total newbie to any CAD, much less 3D modeling, trying to recreate those features seems kind of daunting; it took me forever just figure out how to reconstrain the trimmed dang notches! :) Smarter to just make a rectangular nut a al my current design, but a bit thicker, and just sand to the trapezoidal shape and file the angles into the notches than stress over the CAD design. OR... use it as an excuse to dig deeper in to FreeCad and really learn something?

AND.... a dumb question. Every nut I've replaced on violins and celli, I've replaced because the original nut came loose or fell off. How do I remove, safely, the nut on the SRH500F? It appears to be glued on pretty solidly, and the headstock is covered with an el-cheapo paper-thin laminate that is kind of wrinkled up onto the base of the nut, like a bad linoleum job.

Thanks!
 
#14
Can’t help on the 3D modeling but to remove a nut I always score all the way around it with a new, sharp Xacto, carefully, don’t slip and scratch the finish. Then for something more Gibson / Les Paul style put a piece of wood against the fretboard side of the nut and lightly tap the wood with a hammer. For a Fender style notch the fretboard side tap can still help loosen it up but I’ll pull it out with fret end nippers, gently rocking back and forth as I pull up. You could also carefully tap it out from the side with an appropriately sized punch or wood block.
 
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#15
Like everything else, angled stuff has a lot of ways to do it. MY way would be to create a new plane at right angle to the part you want to slope, draw a triangle with a side covering the entire part of the nut you want to remove, and then extrude the triangle through the nut. When you do that, choose to cut the original body, and it'll chop off the sloped part.

But, I wouldn't actually do that. Since you're 3D printing it with filament, you'll get stair-stepped faces that aren't very nice and will end up needing sanding. Leave it square-edged. It's fine for the nut, will work no problem.

Recommend watching videos by twoodford on YT for info on nut replacement. He's done a bunch of them. You'll need to cut through any finish or laminate attached to the old nut and then use a block to knock it free.
 
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#16
You guys are the best! I managed to draw a triangle on one side face in the shape of what needed to be removed to get the trapezoidal shape, then use the "Pocket" command to slice it off, kind of how you suggested! I might print one more out w/ PLA just to see what it looks like, but I think it's pretty close now. Just have to get up the nerve to follow the suggestions as to removing the original nut.... :)

Thanks again, Cat and Matt!
 
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#17
Being a SolidWorks person one way to make nuts is an Extruded Boss/Base. Just draw out your complete profile then draft the top surface and string slots. Ideally IME though the slots are drafted left and right a tiny amount and the bottom is radiused using a revolved function. I think with your materials and FDM you will have a bit of leeway here though.

Print wise if you lay the part down on the face that points towards the bridge you won't get that sort of scalloped topo map effect but rather just lamination lines. I wouldn't bother with printing it hollow just go with 100% infill as it's a small part and could use the mass for strength and "tone". You could also use a .02mm nozzle for more resolution if you wanted.
 
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#18
Arie X said:
Being a SolidWorks person one way to make nuts is an Extruded Boss/Base. Just draw out your complete profile then draft the top surface and string slots. Ideally IME though the slots are drafted left and right a tiny amount and the bottom is radiused using a revolved function. I think with your materials and FDM you will have a bit of leeway here though.

Print wise if you lay the part down on the face that points towards the bridge you won't get that sort of scalloped topo map effect but rather just lamination lines. I wouldn't bother with printing it hollow just go with 100% infill as it's a small part and could use the mass for strength and "tone". You could also use a .02mm nozzle for more resolution if you wanted.
Click to expand...
hi, honey!
 
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