DIY setup out of frustration

Glad I could provide some inspiration!

LorenFL said:

Bought some super glue yesterday to fill my E slot. (it's currently got a piece of paper under the string) Trying to decide if I want to do that, or just start with a new nut blank. I guess I'll go the easy route first just so I can say I did.

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I ended up not doing this. I got to reading about compensation at the nut, which is something you don't hear about much on ukuleles. But, it's not uncommon on guitars.

I'll spare you the gory details, but I have a theory based on measurements of my uke and some research.

Ukes used to be built with the frets placed using "the rule of 18". The spacing of the next fret was exactly 1/18th of the remaining scale length. Modern ukes are built on more precise math. They use a number that's exactly 17.8-something for precise fret placement. And then they always have to add some "compensation" at the saddle to account for the string stretch when you fret a note.

The old method automatically incorporated that compensation at each fret by making each fret just a little longer!

So, my theory is that modern factory-built ukes are nearly perfect in dimension. I measured a lot of things on mine. 15" scale. Exactly 7.5" 12th fret. First and second frets EXACTLY where they should be according to the Stew-Mac fret calculator. It's built to mathematical perfection. BUT... that perfection doesn't take into account the string stretch!

So, on my uke, I first adjusted the action at the saddle and nut. Better, but still not perfect at the 12th fret, and even less perfect at the first and second fret. Not bad. Playable. But, more error than I was happy with.

Then I read about nut compensation, and even one anecdotal post that said some luthiers will place the first fret at the same span used for the second fret. On a concert scale uke, that's a difference of about 1.2mm. Interesting.

You can experiment with this with zero risk by just shimming a piece of wood under the strings right in front of the nut. I got out my trusty utility knife and sliced a sliver of pine from a board out in the garage (because I couldn't find a square toothpick or a matchstick). Whittled it down to about 1.5mm width and just taller than the height of my strings off of the fretboard. Wedged it in there, and retuned. WOW! Amazing improvement in low-fret intonation!

Then, I took a breath and yanked the old nut off. (came off easily, but it is a bit intimidating) Grabbed one of my new nuts, made some measurements and marks and filed a .75mm relief in the nut so that it can hang over the fretboard. I also filed a little bit off of the bottom of the nut so that I don't have to cut the slots so deep.

The result? Near perfect intonation without having do go dangerously low on the nut slots! I'm within +/- 2 cents at the 12th fret. Within +4/-2 at the first fret, and +/- 2 at the second fret except for the E string. It's off by as much as +8 on the first fret. That's checking with an app on my phone that gives me 1-cent accuracy. On my cheap tuner that only shows increments of 10, it looks perfect!

So, I could (and probably will) do a little more work with that nut compensation and add some custom compensation to just the E string. Then I'll put on my new strings and hope things don't change too much!

It's amazing how much you can improve a setup with just a little knowledge and experimentation!

Here's a photo of my under cut nut. It needs a little more work, and then to be glued in. But, a picture is worth a thousand words.

Spent a few more minutes on the nut. Turns out my "0.75mm" was more like 0.6ish. I wanted more compensation on the E string, so I angled that undercut to the A side and made it 0.65 at the G and 0.75 at the A.

Tuned it up and checked it. All was REALLY good, but now the A string is slightly overcompensated and goes 3 cents flat on the first string.

So, I filed .25mm off of the face of the nut at the A string to decompensate it a little bit.

Now, absolutely everything is within +3 to 4 cents!

My ukulele is now more in tune than I am.

Time for a quick update on my DYI setup journey. I already received some of the nuts and saddles I ordered so I decided to get some extra tools and start working on my KoAloha soprano. I've had some real issues with that one since I first got it. Originally the G and A strings had a horrible chime or buzz to them because the nut slots were cut poorly. I brought it to my local luthier who was able to cut the slots properly without having to raise the nut but after that the action at the nut was absurdly low, closer to 0.25 mm, which in turn caused a bit of buzzing when some of the strings were played hard. The issue didn't usually manifest itself during normal playing but it still bothered me. Additionally, I noticed that some weird grooves had appeared on the saddle and if the strings were in those grooves they buzzed incessantly. I now wonder if my cheapo hard case that I used to store the KoAloha in caused those grooves, maybe while the not-so-soft padding was pushing against the strings, saddle and bridge. Anyway, that issue was fixed with just moving the saddle a bit to the side so the strings wouldn't be in those groves anymore, but I was still really annoyed by the saddle and there was still that slight buzzing issue. The action at the 12th fret was also really low (in addition to the action at the nut) so I thought there was plenty of leeway to bring it up by making a new saddle for the uke.

Since the KoAloha saddle is quite wide I didn't have much choice when ordering replacements. I did order a wide enough straight topped saddle but I also wanted to try a compensated one since the stock saddle is also uncompensated, so I also ordered a compensated classical guitar saddle with the intention of cutting it down to uke size since the compensation seemed to fit ukulele strings. I easily cut down the saddle with a saw and sanded the sharp edges a bit and also thinned it a bit by sanding in order for it to fit in the saddle slot. That was the easy part, but then I noticed that the acoustic guitar saddle is, of course, slanted so the G string ended up being slightly higher than the A string. Not so much that it would affect playability too much but I knew it would still annoy me to no end. So, I tried to sand down more on the side of the G string while I brought the action down at the 12 fret, it originally being over 3 mm with the new uncut saddle. I think I managed it quite well as the action now stands at just a tad over 2.75 mm which is decent for me considering the low action at the nut. The base of the saddle is a bit uneven since I had to try to sand it more on the G string side but I doubt that matters too much. Initially, I didn't notice any degradation on the sound quality of the KoAloha, and I actually think it might be a bit louder now. There's still a very slight buzz on the C string when plucked really hard. I doubt that the buzz will be present during regular playing but I'll have to monitor it, same with the sound quality overall. It doesn't seem that the compensation did much to improve intonation at the 12th fret but it's still decent and definitely not worse than before. Obviously, the new saddle doesn't sit as nicely flush as the stock saddle but I'll take function over form any day. I'll have to keep testing the uke more and decide whether I want to replace the nut as well to bring the action just a tiny bit up to get rid of the buzz, but overall I'd say I did a decent job on the saddle at least.

Nice!

Oh, btw, I found a new tuner app for Android that does 0.1 cent readings. Super-precise!

It's called A-Tuner Lite. (or, you can pay $2.99 to get the full version with no ads)

I don't like tuner apps that much since they pick up other sounds as well meaning you have to tune in complete silence. Granted, they are good in a pinch if you don't have your tuner with you. I use my Peterson clip-on tuner for tuning and testing intonation.

Good work Dohle. Making saddles and nuts will get better with practice. Over the last 10 years I have made a couple nuts and saddles myself. The first was the worst. After that my results got more consistent. I start with a bone blank a little oversized. Fortunately I found a very nice finishing flat file that gets a very nice smooth flat finish on bone.

Made a new saddle myself today to eliminate a buzz on a wound 4th string. I swear my replacement bone saddle fit and looked better than the Corian saddle it replaced. My process is very manual with constant measurements. Lots of sanding and filing always leave a few fingers sore.

Thanks! I'm not quite finished with the new saddle on the KoAloha. It's sticking out a bit too much on the left side so my hand sometimes gets caught in it. I need to chamfer the edge like on the stock KoAloha saddles to make it more comfortable. I won't do the same to the other side since it's not necessary. The result will be a funky asymmetrical saddle. Luckily I don't have OCD for that sort of thing. It'll be an easy job but I haven't bothered with it yet because I'm waiting for the rest of the saddles and nuts I ordered for the Kamaka so I'll do all of them at one.

I did some other kind of DIY stuff today. I noticed that the fretboard on my Kanile'a had shrunk a bit because of low humidity and the frets have started to poke out causing some sharpness. I bought some sanding blocks to shorten the fret ends and I did a decent job fairly quickly and easily but the edges of the fret ends are still sharp. Now I need a fret end dressing file to round the edges off so I'll go get one tomorrow. It's probably good to have one of those anyway in case the same happens to one of my other ukes. I'm not nearly as stressed out about this little issue as I've been over the nuts and saddles.

The amount of tools I've gotten over the last few weeks has been quite substantial. I'm getting more and more into this ukulele DIY stuff.

I'm wondering, why not just buy OEM KoAloha saddles? Then you don't have to mess with all this trimming.
When you properly humidify the fretboard wouldn't it expand? Then the frets would stick out and you don't have to do all this fret work.

clear said:

I'm wondering, why not just buy OEM KoAloha saddles? Then you don't have to mess with all this trimming.
When you properly humidify the fretboard wouldn't it expand? Then the frets would stick out and you don't have to do all this fret work.

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There's a few issues with that. First of all, I've no idea where I would buy stock KoAloha saddles. I actually reached out to them and asked if they could sell me a stock nut and saddle. They said they'd send me those for free. Over two months later, I haven't received them. I sent them a message asking if they sent them in the first place but haven't received an answer (which btw I'm not upset about, I'm not one to complain about not receiving free stuff). Doesn't really matter because I wanted to raise the action anyway and I couldn't do that with a stock saddle, at least assuming it's cut similarly as the stock saddle I have. And in any case, making a new saddle was pretty easy.

Regarding the fretboard, I did try humifying but since it's winter and really cold and dry where I live the frets were still poking out a bit. Before the fretboard got dried up, the frets were already on the edge of being sharp so I thought I might as well dress them properly. It's not a massive effort either.

Update time again. The rest of the nuts and saddles arrived just before new year so I finally had some time to fix the Kamaka yesterday. The new saddle was identical to the stock one. I only had to sand it a bit to make it thinner but otherwise it was a perfect fit. I didn't adjust the height at all because I wanted to leave the action fairly high at the saddle/12th fret to avoid buzzing when lowering the action at the nut. The action at the 12th is now almost exactly 3 mm which is still fine for me. Sanding the nut so it would fit in the nut slot was a bit more work but fairly straightforward. I wasn't actually able to find a high enough nut with the original 28 mm string spacing so I had to settle for one with 30 mm string spacing and narrow it slightly for it to fit on the neck. The string spacing is still fine for the fretboard and it now reminds me a bit of my aNueNue Moon Bird where there's very little space between the outer strings and the edge of the fretboard.

Once I was done sanding and fitting the nut, it was time for the dreaded nut slot filing again. I tackled the C string first since that was the hardest to get right last time. It took quite a while but I managed to get it low enough for comfort and decent intonation while experiencing no buzzing, somewhere between 0.5 and 0.6 mm. After that, the other strings were much easier to handle since there's usually a lower risk of fret buzz. I did have some issues with buzzing caused by the string moving in the nut slot because the slot width wasn't just right for certain strings. I'm not sure if it's because the nut slot is too wide or too narrow for a string but I got most of the slots sorted with some tweaking. The G string still has a slight buzz when plucked really hard but it's not at all noticeable when playing normally so I might just leave it at that.

I have to say that the difference in terms of playability and sound on the Kamaka is huge compared to before. After the setup, I simply love playing it. I think the intonation still isn't absolutely perfect and I doubt it will ever be because of the nylon strings. To be honest, I really don't want to tackle another uke with nylon strings again. Filing the nut slots is just such a pain with the balance between intonation and buzzing. Fluorocarbon strings seem to be much easier to deal with. It seems that you can actually leave the nut slot quite a bit wider than the string gauge for a fluorocarbon string. I noticed this after I decided to tweak the Kanile'a a bit more and a string started buzzing when I tried to narrow the nut slot. Widening it got rid of the buzzing immediately.

Great stuff!

I still haven't bothered to put my new strings on mine yet. Much like you, I've dialed in the intonation to where it plays great and sounds great... I'm just gonna play it for a while!

This week I did something a bit different in terms of my DIY journey. A few months ago, I bought a fairly cheap concert uke, a Kai KCI-5000 to be exact. I bought it from Thomann so it basically came without a setup. It's a nice instrument for the price. Solid acacia, ebony fretboard, slotted headstock, side soundport, cost me about 200 Euros. When I started doing the setup myself I noticed that the nut and saddle were some sort of horrible plastic. After setting the action at the nut, the intonation was ok at the first fret but quite awful at the 12th. It had a straight plastic saddle without any compensation, so I thought I'd do a little upgrade on the thing.

I ordered some blank nuts and saddles with the intention of upgrading the plastic ones to GraphTech TUSQ and making a compensated saddle to improve intonation. I first sanded down the saddle to the correct size (not the quickest task since the blank block of TUSQ was quite big) and then started to file the saddle for the compensation. I filed the saddle so that the breakpoint for G and A is at the very edge of the saddle towards the nut and C is the opposite, on the far edge of the saddle, easy peasy. But I wanted the breakpoint for the E string to be in the middle so that was a bit trickier since I had to file on both sides of the saddle and sort of meet in the middle. I managed it in the end but it certainly doesn't look like a professional made it. Quite messy in fact. But the most important thing is that it works. I tested the saddle with the original nut still in place and it made a huge difference. Previously the C string was something like 30-40 cents sharp but now it's maybe 5. The other strings are also within about 5 cents at the 12th fret. Great success.

The nut was the easier part. I again sanded it down to about the same size as the original nut, took measurements for where the nut slots should be, and just filed away. I'm still having some trouble with certain strings (particularly the C) buzzing in the nut slot but I think the issue might be how I'm cutting the angle of the nut slot instead of the actual width of the slot. The C string was again buzzing quite a bit but I did a few corrective strokes with a slightly narrower nut slot file so that the nut slot would have a smoother curve towards where the string meets the tuning post. That got rid of the buzzing completely, so I'm quite happy with the result and the fact that I'm learning to cut the slots better every time I try. The intonation at the first fret seems to be even better now than with the original nut after my initial setup. Not sure if it's the material of the nut or the better job I did with the setup but I'm really happy with the result. I was actually thinking about selling the uke after I'm done fiddling with it but it actually plays so well now that I just might keep it as a travel uke maybe. I'll have to test further and see.

Next I'm going to make a new nut for my Kamaka similarly as I did for the Kai, i.e., from a blank nut. The nut I made previously had wider string spacing compared to the stock nut so I want to correct that. It's still playable with the wider string spacing at the moment but the strings are maybe a bit too close to the edges of the fretboard. After that, I'm probably finally done with the Kamaka.