PDA

View Full Version : Build Question



saltytri
11-20-2011, 06:27 AM
When building a concert with a convex top (25' radius), is the fretboard at a right angle to the surface of the box where the heel of the neck attaches?

Thanks!

Rick Turner
11-20-2011, 10:08 AM
Yes, No, Maybe, Sometimes.

Sorry, but that's how it really is.

Allen
11-20-2011, 10:15 AM
Depends on lots of factors such as how thick the fret board is, and fret hight. The bridge hight and how much saddle you want protruding. String choice and what RH the instrument was built in and where it will live. What sort of relief you are shooting for. They all affect the geometry in little ways. So yes, that's how it really is.

Rick Turner
11-20-2011, 10:24 AM
One trick...make the geometry of the neck block end of the sides and the upper bout of the top be a 90 degree angle and then do any doming below the soundhole.

I avoid the whole issue by floating the fingerboard above the top. Dirty, cheap trick with lots of benefits... Think on this: You don't see violin makers gluing the fingerboard to the top...

Pete Howlett
11-20-2011, 01:15 PM
And you don't see violin makers screwing their bridges to the tops either ;)

saltytri
11-20-2011, 01:50 PM
Thank you, gentlemen. I suspected that this isn't a simple matter but is it true that the main goal is to get the strings at an appropriate height at the 12th fret and at the saddle?

Actually, I was thinking of floating the fingerboard as Rick suggests (like his Compass Rose designs). Yes, I do have the carbon fiber to reinforce the floating end.

This is my first acoustic build and I'm trying my best to keep things within tried-and-true practices and dimensions without taking any big flyers. None of the instruments I have on hand have radiused tops, though, so I'm feeling my way in that regard. I'll mock up and/or diagram the relationships before using any glue.

Here are some photos. The woods are padauk and cherry.

301613016230163

I know that padauk is not the most common choice, especially for a beginner, but I had a pretty decent board in my pile that was just big enough to get out a back and sides. The cherry top is perfectly quarter sawn and seems like a color that will go well enough with the padauk both now and as it darkens over time. I wanted to use a hardwood top so that no binding will be necessary. I'll save that part of the learning curve for later.

saltytri
12-16-2011, 08:44 PM
It worked out fine with the fretboard close, but not quite, to perpendicular to the heel block. I fiddled around with the angle and fit until the clearance at the 12th fret was right and the strings landed on the saddle at an appropriate height. I see what Rick means by, "Yes, No, Maybe, Sometimes."

Once the bridge glue is up to strength tomorrow, the strings will go on and I'll finally get an idea what it sounds like.

The finish (after filling with epoxy) is as recently described by Duane - 6 coats of nitro lacquer, two weeks of cure, wet sanded up to 600, then rubbed with Wool Lube and 0000 steel wool. Topping it off with hard wax brought out the sheen nicely. My wife laid claim to this one early on and it's a good thing that she prefers satin to gloss because the underlying work really isn't good enough to support a gloss finish. The pros have nothing to fear from me but the appearance is quite acceptable for the first try.

RuckMonkey
12-17-2011, 12:58 AM
My goodness that is LOVELY! To my eyes if you didn't say it was your first build, I wouldn't know. Really lovely.

0011000011001
12-17-2011, 04:25 AM
@ Saltytri,
The bridge on that uke is very nice! im nearly finished a concert build and im very keen on trying that type of bridge! i have a vague idea of how the string mount but im not 100% sure. Do the strings just got through the holes with a not underneath the soundboard?

saltytri
12-17-2011, 04:32 AM
That's almost right. I'm new to this so don't take my word for it but I believe that the way you describe it is an accepted practice, provided there is a bridge plate made of a reasonably hard wood so the knots don't damage the sound board. On this one, the strings don't go through the top. The underside of the bridge is routed out so that the knots are tucked back under the bridge. Copied from a Mike Pereira design! :o

Moore Bettah Ukuleles
12-17-2011, 05:26 AM
That's a very attractive uke. (I like your label too.) The only problem I can see with that type of bridge is the reduced foot print size.

saltytri
12-17-2011, 06:08 AM
The only problem I can see with that type of bridge is the reduced foot print size.

Good point, thanks. That's the kind of feedback I'm looking for. Now that I look at it in that light, the MP version is quite a bit longer and wider (though the example I followed is on a tenor, which also explains the bigger size). I suspect that Mike has the footprint issue figured out because that tenor puts out plenty of very sweet sound.

saltytri
12-18-2011, 10:30 AM
Here's a sound sample with Martin fluorocarbon strings. The instrument sounds uncannily like my MP mahogany and WRC tenor, but with a bit smaller voice. The sustain goes on and on. It isn't as loud or as fulsome as my Koaloha Pikake concert but that is a killer instrument, after all.

http://www.4shared.com/audio/Tv4Xir5c/sample1.html

31195

erich@muttcrew.net
12-18-2011, 12:23 PM
http://www.4shared.com/audio/Tv4Xir5c/sample1.html

I'd love to hear your sound sample, but the link isn't working for me.

saltytri
12-18-2011, 12:32 PM
This is my first effort at recording and posting. I went to the host site and made a change that I think will allow others to listen. Would you let me know if it works now? Thanks!

mzuch
12-18-2011, 02:05 PM
Yes, it works. Great job.

saltytri
12-19-2011, 04:01 AM
Thanks, Michael. And I'm gladdened by your site, both the concept and the instruments.