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ruby50
05-22-2016, 07:24 AM
I found this video by Ken Timms on measuring bridge blank height:

https://www.youtube.com/watch?v=fqshLtHjVJI

I don't yet need to make the simple and cool jig for determining the height as I can do it with a rule for the first couple, but a question.

On a guitar, you make the bridge thickness the height of a straightedge placed over the fretted board (within limits), then add the saddle at twice the height of action at the 12th fret. On Ken's jig he has a small notch cut at the end - 1'8" or so - and it looks like he is making the bridge that much taller than the straightedge placed over the frets.

Is this right? How tall is the saddle sticking out of the bridge? Is there a desirable height of the strings above the uke top?

Many thanks

Ed
Having more fun than I can stand

Timbuck
05-22-2016, 08:18 AM
Yup! That is the way I do it ..I allow for about 1- 1.5mm saddle hight on my sopranos ... I have seen some ukes with the saddle sticking up as far as 6 - 7 mm just to get the right action (to me this looks bad) ...I think that this what happens when the builder adds a neck angle of 2 or 3 degrees like on an arch top guitar, or makes the fret board too thick...I build mine with zero angle and a thin .090" fretboard...if you look at some of the early classic island style ukes Nunes etc...you will see there is no saddle or fret board ..just a small ridge at the front of the 1/4" bridge.
This is the type, but! it's a bad example of a bridge co's the slots have been cut too long weakening the bridge and causing a very sharp a break angle in the strings.
http://i219.photobucket.com/albums/cc143/shiregreenbod/saddle_zpss3jd7xos.jpg (http://s219.photobucket.com/user/shiregreenbod/media/saddle_zpss3jd7xos.jpg.html)

ruby50
05-22-2016, 11:14 AM
Thanks Timbuck, but I am still unclear as to how thick to make the bridge - the same as the straightedge on the frets, or with the cut out I see on your jig - and how much is that cutout for a soprano.

Thanks

Timbuck
05-22-2016, 09:52 PM
:o
Thanks Timbuck, but I am still unclear as to how thick to make the bridge - the same as the straightedge on the frets, or with the cut out I see on your jig - and how much is that cutout for a soprano.

Thanks
The 3mm cut out on the stick gauge is where the top of the bridge is to go..I measure the required height of the bridge with the wedge gauge, then sand down an oversize bridge blank to that size (usually about 6mm but it varies) I then make an ebony saddle to stand proud of the bridge at approx 1.5mm...this gives me about 3mm action at the 12th fret .. I then slightly adjust the saddle/bridge using a steel straight edge for reference, until i'm satisfied.

Theoretically! if the fret board was perfectly parallel to the soundboard (and it usually isn't, co's we are working with wood and there is a slight radius on the lower bout to allow for) then to get a 3mm gap at the 12th using "Stewmac narrow medium fretwire" the bridge/saddle height should be 6mm + fret board thickness + crown height of fret... Therefore 6mm + 2.3mm + 1mm = 9.3mm total (less lower bout radius height) ;)

BTW I'm fitting bridges at the moment on a batch of 5 sopranos.

ruby50
05-23-2016, 01:43 AM
Got it - 3mm above the line of the fret plane. This approximately what is shown on the Grellier plans of the Martin soprano that I am using,

Thanks