bridge placement & compensation

[Michael Cyr]

I'm building an electric low G tenor ukulele using nylon strings and bone nut and bridge. The string length is 17 inches. My question is do i place the bridge edge ( that is the edge facing the nut) at exactly 17 inches from the nut edge making the free vibrating length 17 inches? From what i read compensating on the bridge is filing the bone edge slightly effectively making the string length a little longer. Ive been trying to research this and found that a lot of people say they move the bridge back 1 or so mm from the start but being new at this what exactly does "back" mean? Towards the nut or away from the nut? And why? My tendency is to go with the exact 17 inches and take it from their with this being my first build with frets.

[Barry Daniels]

I don't build Ukes so my answer is based on guitars. You add compensation to the saddle (not referencing the bridge which can have varying dimensions). The saddle needs to make the vibrating length a bit longer than the scale length (scale length being defined as exactly twice the distance of the nut to the 12th fret). The amount of compensation added on a guitar is about 0.15" at the halfway point of the saddle between the 3rd and 4th strings. I imagine a Uke's compensation would be a bit less and some research should get you the exact amount.

[Alain Lambert]

On my tenors I am adding 2.7 mm to the 17 in scale length, which result in 434.5 mm nut to saddle distance

[Michael Cyr]

On my tenors I am adding 2.7 mm to the 17 in scale length, which result in 434.5 mm nut to saddle distance

Thanks, but is that measurement to the center of the bone saddle or to the edge of the saddle? (Edge meaning the edge facing the nut).

[Michael Cyr]

Alain i did a quick research of your past posts and found you answered all my questions about this in one post. Filling the frets today and soon will be making the bridge i hope to be finished this week. Thanks to all.

If not too late, her is how I do it.
I glue my bridge after finishing.
My tenor has a scale length of 17 inches which is 431.8 mm
I get correct intonation by placing the saddle CENTER at 434.5 mm form the nut edge, which is 2.7 mm of compensation.
I use a 1/8 ( 3mm) saddle so this give me +- 1.5 mm of adjustment for fine tuning.
I put masking tape where the bridge should go. Then carefully place the bridge so the saddle center is at 434.5 mm and the bridge is square to the center line.
Then I check the left-right alignment by placing a ruler on each side of the fret-board and making sure the bridge (bridge holes) is equally spaced on both side.
Once I am satisfied, I tape the bridge to the top so it does not move. I then trace the outside with a pencil. I also drill 2 very small holes in the saddle slot though the top and place 2 small finishing nails as positioner's.
I can now remove the bridge and cut the tape 1-2 mm inside the pencil line and remove the tape under the bridge position.
The finish under the bridge position is scraped, I use hide glue, so I preheat the bridge put glue under it place it back using the 2 positioner nails and clamp it.
Once dry, I string the uke and use APTuner to check intonation of each string filing the saddle top forward or backward as needed.
This work for me!

[Barry Daniels]

Michael, the saddle measurement should be taken to the high point of the saddle where the string makes it last contact. This determines the speaking length of the string, which is free to vibrate. This will be near the middle of the saddle, but many builders move the point nearer to the front of the saddle and ramp the back of the saddle to provide a bit more support to the string.