Fret Board on Sound Board

AstroEd42

Well-known member
Joined
Nov 29, 2020
Messages
100
Reaction score
5
Location
Branford, Connecticut
Hello
I'm new to the forum and Ukulele building. I have been reading books and viewing You-Tube videos on Ukulele building. I'm not a musician in any form. I've started a Tenor build as a gift to my son-in-law. After seeing different ukuleles I want to go with a domed top and bottom. I feel I have the skills to do this. In laying out what I have to do, I've run into a snag. I've seen in books and videos that with a flat sound board the Fret Board is even with the sound board, and is clamped and glued together along with the neck. Being I want a domed sound board, I haven't seen anywhere how the neck and fret board meet the domed sound board. Is the underside of the fret board shaped to fit the sound board radius in that area? Is the neck and fret board put on high enough to clear the highest part of the radius? I don't have a clue. I looked at many images to try and see how this area is treated, but to no avail. any help will be greatly appreciated.
Thank you
Regards
Ed
 
After seeing different ukuleles I want to go with a domed top and bottom. Ed

Hi Ed and welcome to ukulele building. It's a lot of fun.

My advice for a first time builder is to NOT radius (dome) the soundboard. You can build a perfectly good, even great sounding ukulele with a flat top. By radiusing the the top you bring in all sorts of issues you might not want to deal with down the line in the build. For instance, you will have to radius your bridge to match the radius of the top. Do you want to radius the fretboard also? The sides will also have to have a radius to match the top when it comes time to glue the top to the sides and all this requires a radius sanding dish. By all means, radius the back because there are less issues than with the top and I believe it helps the sound.

Others might not agree, but I think if the first time builder sometimes bites off a little more than they can chew and it tends to discourage them and the instrument never gets built. Plan on radiusing the top on your second build because once you start, you always want to build a better one.

But if you insist, the answer to your question is that the top is a compound radius and generally the area just under the fretboard will be flat thus the flat fretboard lays flat to the top.

Good luck and send pictures!
 
Ed.
I would recommend a radius on the top..not a dome. When making the ribs on the top do not sand the rib under the fret board to match the top radius...leave it flat. The top wood will be ok with that.
Tom
 
My soundboards are a compound radius with a flat upper rim to the sides. The area where the fret board contacts the soundboard would have very minimal shape to it.

Your challenge doing this is to get the pitch of the neck when it's fit to be correct so that there will be appropriate relief / space between the bottom of the strings and the soundboard where it meets the bridge. In most plans this number will be somewhere between 8 and 10mm. Depends on the thickness of your fret board and the height of the frets you plan on using. Your bridge will be approximately 6 - 7 mm tall and you'll end up with a saddle protrusion of 2 - 3mm. I'd recommend drawing out your side profile to full scale very carefully to get the idea of what you are hoping to accomplish.

It's quite possible that you will have the fret board fall away form the plain of the neck when its glue to the soundboard a bit when you build in this style.

If you want to be really pedantic then you can make your fret board a bit thicker than you need and your fret slots deeper than absolutely necessary. Then once glued up you can level the fret board and add any relief you want. Then fret it.

Be warned that this is very advanced and I'd never in a million years suggest for your first build.
 
Last edited by a moderator:
Most builders who dish their tops are doing so at a very gradual radius. If you're in the typical 20-25 foot radius range, you're talking a very, very small curve over the distance the fretboard contacts the top. It's pretty easy to build with a gradual radius like that and then just flatten the top between the soundhole and the neck joint with two or three swipes of 120 grit sandpaper. Then you have a flat and true surface to glue the fretboard to, and you can focus your energy on the neck angle as Allen mentioned. Even if you choose to build with a flat top and a flat 90 degree neck angle it's still important to understand the relationship between neck angle, fretboard thickness, bridge height, fret height, and action.

There's a lot of stiff structure going on in the upper bout of a uke - there's usually a transverse brace across the top right above the soundhole, and the neck block just past that. Plus you're gluing the stiff fretboard to the top! Unless you're on the verge of being too thin already, the top won't miss the extra few thousandths of wood that is removed from sanding the radius flat under the fretboard. An alternative if that doesn't sound acceptable is to build with a radius in the top, and a flat fretboard, and then once everything is ready for final fitting, use a cabinet scraper to add curve to the underside of the fretboard so it matches the top.

You didn't ask for general advice but I'll give you some - there are a million ways to build a uke, each of us have figured out what works for us. A big part of the challenge of being new is trying to pick through all the bits and pieces of processes and techniques and put it all together into something that works for you. Don't be afraid to ask questions if it's not clear how X technique would work in combination with Y technique.
 
Thank you all for your replies. Wow! What great answers! Your replies explain to me in a moment what I couldn't find searching for weeks. I did not realize the difficulties involved with making a domed sound board. I will take the advice you have all expressed and start out with a flat sound board. Maybe, after I complete a ukulele, or few, :) I will attempt a domed top. The valuable advice you've all given here will be saved by me. The short time that I've been reading the threads in this forum has really impressed me with the knowledge here. The willingness of everyone to share is awesome. I'm waiting on some supplies to arrive and will be able to start working soon. I'll post my progress. Again, thank you all for the help, and have a good holiday.
Regards
Ed
 
Even with a domed 28' top, its super easy and quick to sand flat the area under the fingerboard tongue- you only need to remove about 1/64th of wood.
 
Top Bottom