calculate action

FinnP

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I just made a new saddle on my concert ukulele and and raised the action from 2,2mm to 2,55 mm on the 12th fret.
The effect on sound is dramatic, and I believe I just got the right action to make this uke sing (Imua ICN). Intonation i near perfect with the new saddle and plays fine, but after I inspected the nut I noticed it was too high compared to my Kaniea K1 concert. The action on my Kanilea is 0,35mm on first fret (open string from top of fret). The Imua is 0,80mm.
I know the rule to calculate saddle height, but how will lowering the nut affect the action on the 12th fret? e.g. if I lower the nut with 0.30mm what will the action the be at the 12th fret if was 2,5mm before.

The Imua feels good, and I'ts not a problem fretting notes on the lower frets. Intonation is perfect on the lower frets too, so I'm a little confused, as this should be a problem with a high nut.

Is there any other reasons than playability and intonation to have low nut?
 
Based on what you said, I wouldn't change it from how you have it right now. Don't even worry about comparing it to another uke. What works well on one might not work as well on another. It sounds like you have it dialed into a place you really like. So just enjoy it. That's my advice.

To your final question, I'd say...No.
 
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I agree. If it feels and sounds good, it is good:).
I tried to measure the action on the 13th fret with a capo on the first fret, but I guess this won't show the approx. action on the 12th fret after lowering the nut.
 
Since the 12th fret is half-way between the nut and saddle, any change at the nut will result in half that change at the 12th fret. So decrease string height by .3mm at the nut will decrease string height at the 12th fret by .15mm
 
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Since the 12th fret is half-way between the nut and saddle, any change at the nut will result in half that change at the 12th fret. So decrease string height by .3mm at the nut will decrease string height at the 12th fret by .15mm

+1 to this ^^^ :)
 
Since the 12th fret is half-way between the nut and saddle, any change at the nut will result in half that change at the 12th fret. So decrease string height by .3mm at the nut will decrease string height at the 12th fret by .15mm
I guess you're right. So I'll be back where I started:rolleyes: Lesson learned. First nut, then saddle.
I wish someone would invent an adjustable plastic saddle and nut, so you had the exact measurements to work with.
 
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Lanakai now uses an adjustable saddle on one model, but it looks weird.

http://lanikaiukuleles.com/product/lutu-11s-mahogany-soprano-tunauke/

They actually had a whole line of those, but they've all been discontinued for a while. There is still some "new old stock" available at places (Musician's Friend, for instance...but they don't even open the boxes of the stuff they sell usually so you'd be at the mercy of Lanikai's quality control). You can adjust those saddles forwards or backwards for intonation adjustments, but not raise or lower them for action. I guess if you removed them you might be able to sand them for height, but I don't know...They never really took off.
 
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