First archtop tenor uke

After reading lauburu’s archtop uke post in early December I did a little searching on Google, Youtube and the UU forum to learn what was special about the archtop and how it’s made. I also consulted Benedetto’s book ‘Making an Archtop Guitar’.

I then decided I’d have a go at carving a top. Since it’s only possible to learn/evaluate by completing an instrument, that’s what I’ve done. I greatly enjoyed this process: it gave me a bigger buzz than making my first conventional tenor uke.

It was designing ‘on the hoof’ using my existing tenor mould as the basis for the project. It was immediately clear that for a 17” scale length, 15 frets to the box would be better than the usual 14.

The only new tool I acquired for the project was a Chinese made 1.5” convex soled plane (£15 inc postage) used for shaping the inside of the top and back. No new jigs or cauls were needed.

As this was a learning exercise, I saw no reason to purchase any (expensive) materials but to use what was to hand. The top was made from 2 pieces of new quarter sawn European Lime. The back is a single piece of mahogany from a Victorian chest of drawers. The sides are recycled sapele, the neck is new sapele, the tailpiece is ebony and the binding is maple. The finished weight complete with machine heads is 575 g ( 20.4 oz) which is in the same range as my normal tenors.

The instrument took approx 90 hrs over a 16 day period. The top is finished in polyurethane lacquer, the remainder in Truoil. It has been strung with Aquilas and has a temporary bridge to get me going: mostly I now use Worth brown or Living Waters.

I’m pleased with its appearance: the next one will be better with a spruce top and made in less time. However this was an exercise to learn to carve an archtop and to make a different type/sounding uke, so was I successful? As it stands this instrument is loud as are all my tenors but this one has great projection. It sounds crisp and clear with good note separation: it has a little less sustain than my other ukes. The sound is different, perhaps more guitar like. It feels different when played, more responsive. So I’m happy with the way it sounds. As I’ve no archtop uke with which to compare I don’t know whether I’ve unlocked its full potential. Getting the best out of an archtop will be the subject of a subsequent post.

Very nice! How does it sound?

Just awesome, I applaud you job well done

That looks fantastic.

I think I just fell in love

That's a beauty! You wouldn't happen to have a link to the plane you bought, would you? I've been looking around online haven't seen anything as inexpensive as that. Thanks.

Matt -this is the link to the plane I bought. This really is the tool I used after doing the usual drilling on the inside. As we say 'you pays your money and you takes your choice' -it did the job for me!

http://www.ebay.co.uk/itm/1pcs-Conv...8-planes-woodworking-tool-1293-/111545734458?




I was thinking about making some planes: I made the one at the back the other day-a bit larger than the Chinese one and a bit crudely done but it works fine. I lack patience and never do anything properly first time.

Thanks Greenscoe! Saw this one out there, too. Costs a little more, but looks pretty good.
http://www.ebay.com/itm/Thumb-brass...cello-bass-woodworking-tool-585-/390909529656

In making my first archtop uke, I was trying to get an understanding of the structural requirements of the archtop soundbox together with an appreciation of the necessary acoustic properties primarily of the soundboard and back. I was trying to derive a new set of rules.

It’s often said that a uke is not a guitar but much of the information available for archtops relates to the guitar (incl Benedettos book which I followed) not the uke. Now that I have a little knowledge, I’d like some input from others who have made archtop ukes.

2 mm would be a good starting point for the thickness of a tenor back. The steer I got for an archtop was 3 mm at the centre tapering off to 2 mm. This seems reasonable since there are no cross braces. Are these the dimensions others use?

For the top, 4 mm tapering to 3 mm intuitively seems too thick/stiff: but again there are no cross braces and only 2 lengthwise braces. Benedetto says beginners make their (guitar) tops too thin but is a thick top necessary for a uke?

In making my top and back I tap tuned them, reducing the thickness and flexing them whilst tapping and listening for a clear resonant response as per Benedettos instructions. I believe I achieved this. Is this appropriate for the uke and do others do it?

For me the most perplexing part of making the archtop uke was trying to voice the instrument as per Benedetto: this involves working on the recurve, the area of top and back where they meet the kerfing. This I did on the completed box and then again on the completed instrument strung in the white. Material is scraped away from the recurve making the back and top less stiff and ‘unlocking’ the instruments potential. Making decisions about acoustical improvements based on tapping, listening and trying to flex plates is difficult and all this recurve scraping can play havoc with the symmetry and finish of the instrument. I found this to be time consuming but believe I did increase the loudness and improve the sound of the instrument. I would very much like to hear what others have done here. I wonder whether for a uke this voicing is necessary and whether by making the soundboard in particular thinner and more flexible initially this could be avoided?

I’ve not mentioned other factors such as optimum arch profiles, side stiffness, bridge design, but any and all information gleaned from making archtops would be appreciated.

Sharp looking uke! I know you put a lot of time into it.

Are there no archtop makers on the forum? Any advice on getting the best out of an archtop uke would be appreciated.

Great looking archtop! I can't wait to see what you come up with for the next

Hi greenscoe. Congratulations on your latest project. Looks great. I've been living unplugged at the beach for the last couple of weeks so have only just read your post. I'm not an expert by any stretch of the imagination but can share with you what I know.

Thickness of a tenor back. The one I made was roughed out to 3mm but by the time it had been sanded and scraped it was closer to 2.5mm tapering away to 2mm towards the edges. Lots of flexing and tapping rather than measuring the thickness.

Same for the top.

Voicing the instrument was a bit of a dark art and I relied heavily on my tutor (who had worked with Benedetto). Without his help I would have erred on the side of caution and made the recurve section too thick with severe consequences to tone and loudness.

The tone of the finished instrument is much more guitar-like than a normal tenor uke and I'm still experimenting with how to play it and what to play. It seems happier with finger picking and jazz standards than with "rip, sh*t and bust" strum alongs but I've still got a lot of experimentation to do with different strings, lightening the bridge.......... All excellent fun.
I hope some of this is useful to you. Once again hearty congratulations on producing a fine looking instrument and welcome to the ranks of those who have survived making their first archtop. When do we get a sound sample?
Miguel

Miguel thanks for your praise and the info.

I think I may have left the top too thick in the centre as it was roughed out to 4 mm and heeding Benedetto's words I left it thicker than I felt was necessary. I think it has the correct sound for an archtop but is maybe a bit bright. I suspect thinning the top would lower the tone. Your top profile is very different from mine, I wonder what the best profile would be?

I think I had high expectations having listened to your uke: I don't think my instrument sounds as good as yours, hence my feeling that I haven't unlocked all its potential.

Back in 2009 Bradford started a thread here on UU about building "archtop ukes" and other members all joined in on the project using all sorts of methods ....Find it Here
http://forum.ukuleleunderground.com...Building-an-arch-top-ukulele&highlight=arched

Thanks for the info Ken-however I've already found and skimmed through that very long thread. Unfortunately most of the attachments no longer opened for me: I think there were 3 links to other sites that show finished instruments. I got some basic info but not the sort of info that I'm seeking. I've researched various ways to physically make an archtop and I've completed one instrument. I was hoping for some discussion on the key factors to make a great sounding archtop uke: this seems in short supply. When it comes to conventional ukes we are forever debating what part we think various factors contribute to the sound of the instrument.

Edit: I've been back through the thread and the attachments now open. The info is largely on how to make, not factors for achieving best sound. There are several good looking finished ukes which it was interesting to see.

I'm not much of a player and I dont have equipment with which to record. For what its worth on soundcloud are a couple of sound clips comparing one of my sapele tenors with this archtop tenor, theres one finger picking and one strumming. In each case the archtop tenor is played second. I hope you can hear the difference.


https://soundcloud.com/ukes-1/normal-and-archtop-ukes-strumming

https://soundcloud.com/ukes-1/conventional-and-archtop-comparison-1