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quaprappo
01-15-2016, 12:21 AM
Hi all,
i'm quite new to luthery and this is my second instrument: a spruce/mahogany tenor ukulele with a Kanile'a style bracing pattern.
It sounds quite good but has a nasal tone and a resonance on C note played on the A string (don't know if it's a good or a bad feature).

I'm currently improving my design in order to built up a better 3rd instrument.

If you have any suggestion please help me: i'm trying to learn more about this subject.

I hope you'll like it :o

8739087391

greenscoe
01-15-2016, 03:19 AM
Welcome to the forum. You will find lots of useful information and help here.

Its great to hear that you are already planning to make the next instrument: most of us progress quite quickly with each build, and some claim no 5 is often a significant step in their journey to the perfect instrument.

From what I can see you've made a good start and clearly have some ability in working with wood. My preference is always to fit purfling and binding, but they are not absolutely necessary.

You mention improving your design. I don't know what method you used to build the box, but it looks rather flat at the base of the lower bout (though this may be just the photo?). If this really is the case, then a rounder lower bout may be something to consider to improve the appearance thought it wont make it sound better!

quaprappo
01-15-2016, 05:10 AM
thanks for your reply.
the lower bout has a 2.7m radius, i'm planning to go down to 1.5m in the next one.
The top is dead flat to simplify neck attachment.
the top thickness is 1.7-1.9 mm (i didn't have a decent planer, so it's not perfect)
the back and sides are something between 1.9-2.3 mm thick. I didn't take too much care on back and sides.
Neck is bolt in the body whitout any kind of dovetail.
All is glued with epoxy

the result sounds a little dull to my ear (i'm not a well aged musician) and it has a very poor deflection near the bridge.
i'll provide to post an audio test.

I plan to take the top thickness down to 1.6-1.7 in the next project.
I'm still in doubt if keep the current bracing pattern or go back to a traditional fan bracing.
Tap tuning it's wizardry for me, so i tap until i think "ok, it sounds quite good, but i'm too worried to carve the braces more"
I still don't know what is considered a "normal back-sides thickness" but i'm doing some research.
I want to try a dovetail or a tenon neck joint.
Buy some titebond!

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greenscoe
01-15-2016, 06:37 AM
Thats better: more photos help us see what you have done!

Your top and back thicknesses are in the right area. I think most would say the sides should be no more than 2mm, as thicker sides are more difficult to bend.

I see now why the lower bout is flat: the end block is much too large and appears to be flat. It doesn't need to be so wide or thick and should have a slight curvature.

Sorry no more feedback from me-I'm just leaving for the airport!

lauburu
01-15-2016, 08:01 AM
I'm no expert but I see that you have made exactly the same mistakes I made with my early ones - over engineering. The end block is way too big, the sides are a bit too thick at 2mm, the braces look industrial and probably need to be narrowed, the bridge could be trimmed in size...
You could use my early efforts to hammer in nails they were so heavy and strong. They still sounded OK but as I've built up the courage to make lighter and lighter ukes, the sound is getting better. I'll know when a uke is too light when it implodes on stringing up.
Also, suggest you move from epoxy to Titebond (red).
There are so many excellent luthiers that contribute to this forum (I am among not one of them, unfortunately). I suggest you go through the posts and read what these guys have written over the past 12 months or so. We are blessed that they are willing to share their extensive knowledge so that we can learn.
Miguel

Allen
01-15-2016, 09:19 AM
You've way overbuilt the bracing. And that tail block as already mentioned is at least 2 times larger than is required.

Mine are made from 12mm ply and50mm wide on Tenors, with the curve that I want for the butt machined on that mating face for the sides to conform to.

As for top thickness, I wouldn't be going that thin on the next one. Work on you're bracing. You could keep your top at closer to 2mm thick and really lighten up the braces and get a far more responsive instrument.

mzuch
01-15-2016, 09:40 AM
You've way overbuilt the bracing.

I'm not sure that folks understand from the photos that these are suspended braces that touch the soundboard only at their ends. They are, in effect, little bridges that transmit vibrations from the bridgeplate to various spots on the soundboard. Although this bracing concept has been around for a while, Kanile'a has had very good success with it under the name TRU Bracing. I use a somewhat similar method on my tenors. It provides a sweet, rounded tone that I like very much. I believe that the flat bottom also is a Kanile'a feature.

quaprappo, what do you mean by a "very poor deflection near the bridge?" If you PM me, I may be able to help with that.

quaprappo
01-15-2016, 11:53 PM
Thanks for all suggestion.
After that photo i carved braces thinning them from 8mm to 6mm wide.

When you tap tune a soundboard and a back do u look for a particular note?
It's a sort of wizard stuff for me.