Two "waist" curves not matched, why?

The curves at the "waist" of ukuleles (between the upper and lower bouts) are different on one side than the other. They are not mirror images. Why? Thanks.

Badly cut wood?

They should be. The goal is to make them identical. Not always easy to do when you are bending wood.

Can you post photos of the unmatched curves?

coolkayaker1 said:

They are not mirror images. Why?

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So that you will ask why.

Probally using a single bending iron if it's a custom or a asymmetrical mold...

Seriously, I have something like four tenors, and they are all the same that way. This includes custom ukes, like my Kiwaya ctsom tenor made impeccably for NAMM. Pono x 2 (yes, both), Kiwaya, Covered Bridge, etc.

CHekc your ukes (at least tenors). The waist is not symmetrical side to side. I'm just wondering why...perhaps a luthier would know.

As one of many (every) example online, here's a Gibson tenor:
http://www.denverfolklore.com/instrument_photos/Gibson_TU-1_Tenor_Ukulele_photos.htm

The waist is not the same.

Fender
http://www.chicagomusicexchange.com/acoustic/fender/fender-ukulele-hauoli-mahogany-tenor-ukulele/

THey're usually "thinner" on the right side as you look at them, and have a wider/longer waist on the left side as you look at them from the front.

Kamakas, too.
http://www.kamakahawaii.com/


You can only tell in photos straight on. Check your ukes people --it's obvious (for tenors, at least). LOL

mds725 said:

Can you post photos of the unmatched curves?

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mds725, you'r e a logical guy... help me know if I'm losing my mind. Look at any of your tenors straight on. re your waists asymmetrical?

I don't have a tenor but from the links you posted, honestly, I don't see it. Guess that leaves option B.

I suspect your spectacles may require adjustment:

I suspect that Brian is right that bending wood is not an exact science and that it's difficult to bend both side pieces identically. Frankly, I think it adds character to an instrument, sort of emphasizing its handmadeness.

When I visited the Kamaka factory, I discovered that Kamaka's luthiers bend both sides in the same bending device at the same time. I think most luthiers working with these machines do the same thing.



My guess is that this results in as equal a set of curves as is possible, but I suppose it's possible that the two sides might "unbend" a little, and maybe unevenly, during the build process, before the top and back are secured on.

Here's a video of the Mya-Moe build process.



At about 2:16, Char takes a SET of sides and prepares them to be bent at the same time by the same device. I imagine this ensures that the sides are as symmetrical as possible.

Mine look symmetrical - sorry!

Not meaning to change the focus of this thread or hijack it but why are the bottoms of a lot of ukes flat? My lili'u and blugrass tenor and Kanilea super concert all have flat bottoms. My HF-3 and Collings are rounded bottoms. I never noticed with all my acoustic guitars over the years having flat bottoms.

Markr1 said:

Not meaning to change the focus of this thread or hijack it but why are the bottoms of a lot of ukes flat? My lili'u and blugrass tenor and Kanilea super concert all have flat bottoms. My HF-3 and Collings are rounded bottoms. I never noticed with all my acoustic guitars over the years having flat bottoms.

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It's kinda the same with women, some have flat bottoms some have round bottoms, no one knows why..... (Instert twighlight zone music here).

Try tracing a uke on paper then fold in half and see if it is true and not an optical illusion. I dont think too many are perfect

Like human faces..... have you ever seen an image of each half of a person's face mirrored? The left side mirrored, the right side mirrored..... next to each other, they look like two different people.

mds725 said:

When I visited the Kamaka factory, I discovered that Kamaka's luthiers bend both sides in the same bending device at the same time. I think most luthiers working with these machines do the same thing.

My guess is that this results in as equal a set of curves as is possible, ...

Click to expand...

Actually, no, it wouldn't. The radii of the curves are going to be very slightly different (by the thickness of the wood) and you're looking at three different curves (2 "convex" and 1 "concave"). The radius of the bouts is going to be greater on the top sheet and the radius of the waist is going to be smaller on the top sheet. Now, honestly, in the end that shouldn't really matter because they probably go on to put those pre-bent sides into a jig that should hold them in exactly the desired shape before the kerfing, bracing, and top and bottom are added which, of course, serve to lock the uke into that final shape.

But, if we were to assume that the sides being bent in your photograph came out of the bending machine in exactly the shape of the form, i.e. no "unbending" happens at all, and then you traced those sides in a mirror image (or just held them edge to edge) without fitting them into a jig they would be ever so slightly different.

Another way to think of it is this, if the two sheets were bent in a full circle the two circles would not have the same diameter - one would, in fact, fit inside the other.

So, if the builders are bending the sides at the same time, and then not using some form of jig that locks them in shape, yeah...there are probably a lot of very slightly assymetrical ukes out there. I would expect it to be more noticeable on sopranos than tenors, though, because the thickness of the wood, and hence the difference in radii, is a larger percentage of the total radius on the smaller ukes.

In any case, Steve, if you lay your uke flat on its back on a large sheet of paper and carefully trace around it, and you can't find a straight fold down the middle that makes the two halves overlap precisely when held up to a strong light then, yes, the uke is a little asymmetrical.

John

All mine seem fine, even my tenor pono....

coolkayaker1 said:

THey're usually "thinner" on the right side as you look at them, and have a wider/longer waist on the left side as you look at them from the front.

Click to expand...

Well, then, the answer seems obvious. Apparently left-handed players are more likely to be overweight than right-handed players so they give a more generous waist on the left side so it will fit comfortably over a lefty's leg if he flips it... Which, now that I think about it, means I probably was supposed to be born left-handed...

John

23skidoo said:

Like human faces..... have you ever seen an image of each half of a person's face mirrored? The left side mirrored, the right side mirrored..... next to each other, they look like two different people.

Click to expand...

I saw an article years ago where a bunch of eggheads had studied faces and what made people attractive to other people. Their main conclusion (after probably spending way too many of our tax dollars) was that the biggest factor in our deciding whether a persons face is "beautiful" (or handsome) or not is how symmetrical the face is. Other proportional factors (position of eyes and mouth, the "thirds" we all learned in art class) are important but secondary to symmetry.

After seeing that page I think they just wasted a lot of research money...

John