Ukulele Setup

I’ve been doing setups on my guitars for many years, and I thought I would share a couple of hints that may help those of you who would like to work on your own ukes.

The steps of an acoustic guitar setup are usually given as: 1) adjust truss rod to set relief, 2) adjust string height at the saddle, 3) adjust string height at the nut, and 4) adjust intonation at the saddle. Life is a bit more simple with ukes as there is rarely a truss rod, and most saddles are not compensated for intonation. So with a uke we mostly just care about string height at the nut and at the saddle.

As on a guitar I would start with adjusting the height at the saddle. But before doing that I would first measure the action at the nut. That’s because lowering the string height at the nut will affect action at the 12th fret too. If for example the action is 0.040” at the first fret, and you lower it to 0.020”, that would bring the action at the 12th fret down by half the difference, or 0.010”. If you set the action at the saddle first without keeping this in mind you could overshoot and be too low when finished. The usual way to measure this string height at the first fret is with feeler gauges. But if you’re a tool geek like me you could also invest in a nut slotting gauge which really makes these measurements easy.


http://www.stewmac.com/Luthier_Tools/Tools_by_Job/Tools_for_Nuts_and_Saddles/Nut_Slotting_Gauge.html

And for measuring string height at the 12th fret I use:


My target for action at the first fret is about 0.020”, and my target at the 12th fret is about 0.085”. So if I know I have to later lower the action at the nut by say 0.010”, I will target the saddle to give a string height at the 12th fret that is greater by half that difference, or in this case a preliminary target of 0.090” to eventually wind up at 0.085”.

You might wonder why not just set the action at the nut first? You can, but again you have to think about the effect of changing things at the other end. With a little geometry you can show that the action at the 12th fret is reduced by 50% of whatever change you make at the saddle, while that at the first fret is reduced by 5.6%. That is, if you reduce the saddle height by say 0.070” that will drop the string height by 0.035” at the 12th fret, and by 0.004” at the first fret. That 0.004” is not a lot, but it could be enough to cause a string to buzz on the first fret if you set it really low at the start.

So how do you adjust the saddle height? The common method is to draw a pencil line on the side showing how much to remove. In my example above the uke arrives with a 3.0 mm, or 0.120” string height at the 12th fret, and I want to lower it to 0.085”, so I need to remove twice 0.035” at the saddle, or 0.070”. You then sand the saddle across a flat surface (such as a granite tile) with the side of the saddle up against a block to keep the bottom square. This does work, but it’s really easy to mess it up and go too far, or to get an uneven bottom surface. And what if you want to take more off one end of the saddle than the other? I’ve seen several ukes where the string heights were not even, and I needed to remove more from one end of the saddle than the other. Doing that freehand is especially challenging.

Fortunately there is something called a sanding jig that makes this a breeze to do. I first saw a homemade one years ago called the Dickey Saddle Sanding Jig.

http://www.dickeyguitars.com/dickeyguitars/Saddlesand.html


You lightly clamp the saddle in the jig, then elevate the sides of the jig by the desired amount to be removed, push the saddle all the way down, and tighten. If done correctly you now have just the amount of the saddle to be sanded away sticking out proud of the jig. You then sand away until the block hits the sandpaper, and you’re done. The bottom is perfectly smooth, flat, square, and of the correct height. For the measurement you can use sheets of paper or business cards, anything that stacks to the proper height. And best of all is that you can switch things around to elevate one end more than the other before you tighten the jig. Say take 0.050” off one end, and 0.030” off the other.

You can make one of these for just a few dollars. Or…if you’re like me and love tools, you can buy one readymade – the Saddlemaster Saddle Sanding Jig. Here’s YouTube video showing how to use one that you can purchase on eBay.

https://www.youtube.com/watch?v=X2znwaPHhMc&feature=youtu.be
https://www.ebay.com/itm/Acoustic-g...582385?hash=item211171a971:g:KfcAAOSwX~dWpR~G


The final step is to adjust the action at the nut. There is really no easy way to do this without getting a set of purpose made nut files. I like the Gauged Nut Slotting Files made by StewMac:

http://www.stewmac.com/Luthier_Tool...ts_and_Saddles/Gauged_Nut_Slotting_Files.html


For ukulele you could probably get by with only three of them or so. These have a curved bottom profile to give you a nut slot that matches the curve of the string. What you want to avoid is using any type of file that gives you a V shaped nut slot. With a V shape the string height changes when you change string gauge with string types, or from a high G to low G. With rounded nut slots this isn’t an issue. Here of course the thing is to avoid going too deep. I just take it nice and slow, and measure often.

Of course I’ve left for another day discussion of things like being sure the frets are level, or dealing with sharp fret ends that sprout each winter.

Wow
That’s a great presentation!
Can I send you my Uke?
Ron

Wow, what a great resource! I've done setups on electric guitars, but I've never been brave enough to attempt setting up an acoustic guitar or uke. I've misplaced my string action gauge and will ultimately give up the search and order a new one. I'm hoping to be braver someday, so thanks very much for sharing your obvious expertise.

Nice write up, thanks for sharing. I'm going to use your saddle sanding jig. I use the feeler gauges for the string height.

I'm surprised that you don't have one of these, being a "tool geek". I'd like to have one, just not that bad.$$

http://www.stewmac.com/Luthier_Tool...r_Nuts_and_Saddles/Nut_and_Saddle_Sander.html

besley said:

With a little geometry you can show that the action at the 12th fret is reduced by 50% of whatever change you make at the saddle, while that at the first fret is reduced by 5.6%. That is, if you reduce the saddle height by say 0.070” that will drop the string height by 0.035” at the 12th fret, and by 0.004” at the first fret. That 0.004” is not a lot, but it could be enough to cause a string to buzz on the first fret if you set it really low at the start.

Click to expand...

Thanks, I just made a new saddle and forgot to check the nut height first, and had to start over
The above geometry is only true if the string height is is=0 at the 0th fret ,which is not the case. Instead I think it would be more accurate to calculate the action with a capo on the 1th fret and measure the stringheight at the 13th fret.

KamakOzzie said:

Nice write up, thanks for sharing. I'm going to use your saddle sanding jig. I use the feeler gauges for the string height.

I'm surprised that you don't have one of these, being a "tool geek". I'd like to have one, just not that bad.$$

http://www.stewmac.com/Luthier_Tool...r_Nuts_and_Saddles/Nut_and_Saddle_Sander.html

Click to expand...

Well I was going to mention that jig (shown above) since I have tried one - but I sent it back. The way those work is that you extrude the saddle from the bottom by turning screws until the jig no longer rolls freely on the sanding surface, which gives you your "zero" point. But that point is not with the bottom of the saddle flush with the jig, but rather sticking proud about 0.014" or so. You then continue to protrude the saddle using the screws by the amount you need to remove, but you are now doing it by difference, not the absolute amount that is sticking out of the jig. I found this an unsatisfying approach that didn't add anything over my existing jig (shown below). But I will admit that the rolling jig is a beautiful toy.

Wow--very timely as I've spent time this morning on the Stew Mac site ordering tools and supplies for some nut/saddle work on several of my ukes (and nut/bridge work on a nylon-strung banjo).

One of the issues befuddling me is weather to go imperial or metric on some tools that come in both, such as the String Action Gauge. (I won't be springing for any other measuring tools quite yet, but have feeler gauges in both metric and imperial, and a digital caliper that does both.) Obviously with easy online conversion calculators either will work. But metric is more intuitive, while inches are still what I see most often for most action settings. Suggestions on this and other tools welcome!

FinnP said:

Thanks, I just made a new saddle and forgot to check the nut height first, and had to start over
The above geometry is only true if the string height is is=0 at the 0th fret ,which is not the case. Instead I think it would be more accurate to calculate the action with a capo on the 1th fret and measure the stringheight at the 13th fret.

Click to expand...

I must be missing something in your reply, because I don't think it applies.

My calculation is just a geometric treatment of a long box with two vertical ends, and a first fret location that is 5.6% of the total length away from one end. When you drop the far end (the saddle) the amount of drop of the top of the box (the string) at any point along the box (the fretboard) as it pivots from the nut will correspond to how far it is from the saddle. At the saddle you see 100% of the drop, at the 12th fret (50% down the fretboard) you see 50% of the drop, and at the first fret (only 5.6% down the fretboard) you see only 5.6% of the drop. The height of the nut end of the box doesn't enter the calculation at all.

jackj said:

Wow--very timely as I've spent time this morning on the Stew Mac site ordering tools and supplies for some nut/saddle work on several of my ukes (and nut/bridge work on a nylon-strung banjo).

One of the issues befuddling me is weather to go imperial or metric on some tools that come in both, such as the String Action Gauge. (I won't be springing for any other measuring tools quite yet, but have feeler gauges in both metric and imperial, and a digital caliper that does both.) Obviously with easy online conversion calculators either will work. But metric is more intuitive, while inches are still what I see most often for most action settings. Suggestions on this and other tools welcome!

Click to expand...

As for the metric vs. imperial debate, I use imperial just because I grew up setting the action on my guitars to 4/64ths, so that’s what I’m used to. But even though I think in inches, I use the decimal form to make calculations easier. At which point, why not just go metric?

We tool geeks can recommend tools all day. If you are going to try making your own nuts or saddles from blanks, you will reduce your frustration level a lot by getting some type of vice to hold them. Again here is the StewMac option (though of course there are others).


http://www.stewmac.com/Luthier_Tool...for_Nuts_and_Saddles/Nut_and_Saddle_Vise.html


After setting the action the next thing most players would want to do is treat the fret ends for the “fret sprout” that happens as the wood of the neck shrinks and the fret ends “grow” proud of the neck. If the problem is very minor, you can do a surprisingly good job by getting some of those foam fingernail polishing blocks and rubbing them down the edge of the frets. But if the problem is more severe, you’re going to need to get out the files. To start with you can use pretty much any type of file to gently slide along the side of the frets, perpendicular to the fretboard, until you just hear the grinding of the metal cease. I prefer a diamond file, but any type will do. After that take a close look at the sides of the frets. They are typically slanted inwards (beveled) about 35° or so, though on cheap instruments this may not be done very well, and I've seen cheap ukes where the edges are left vertical. So you then take your file and hold it at about this angle and slide along the frets to bevel the fret edges inward. They sell a special tool for this that holds a file at the proper 35° angle, but I find it easy enough to just do it by feel.

The final step is to treat the fret ends themselves, and that does require special type of Fret End Dressing File.

http://www.stewmac.com/Luthier_Tools/Tools_by_Job/Tools_for_Fretting/Fret_End_Dressing_File.html


This special type of file has one dull edge so that you can get into the corner on the sides of the fret to remove the sharp burr there (without damaging the fretboard) and to smooth over the rounded edge of the fret.

Then if you want to work on the fretboard itself, it can speed things up to get the strings out of the way with string spreaders, which save you having to remove the strings for a short job.

http://www.stewmac.com/Luthier_Tool...ts_and_Saddles/String_Spreaders_Set_of_2.html


And we haven’t even gotten to how to level the frets yet.

Ok..I was thinking trigonometry and a right-angled triangle

Great stuff! Thanks for sharing it, and keep those tips coming, if you have time. I've looked over the instructional info on the StewMac website and at frets.com, but I suspect I'll have lots of questions once I start shaping and fitting my nut and saddle blanks.