Pear Shaped Tenor Ukes

[Paul Henneberry]

I just finished a batch of pear shaped tenor ukes and I thought I‘d share some pictures. After making 24 long neck sopranos in all sorts of timbers and basically to the Grellier (Martin) drawings I wanted to design a ukulele from scratch. I love the look of instruments with tailpieces and floating bridges and this was where this project began. Everything that I read about ukes with floating bridges said that they suffered from limited volume so I decided to do as much as I could to overcome that problem. My main approach was to try and maximise the free vibrating area of the soundboard while maintaining the SB area of a traditional tenor shape. I liked the pear shape of the an old Washburn parlour guitar from the 20’s that I had seen and the shape gave me the idea to take some area from around the front bouts of a traditional tenor shape and add it to the back bouts which would increase the width. I build in batches of 4 and decided that two of the instruments would have normal fixed bridges and act as a control to gauge success in overcoming the floating bright attenuation issue. I made all 4 ukes out of exactly the same timbers and to the same scale length and opted to experiment with different bracing patterns to see how they affected the sound.
I read somewhere that there could be an issue with a floating bridge system causing a compression problem just forward of the sound hole. To compensate for this I used an extended fan brace pattern on one of the floating bridge tenors. For the other floating bridge uke I thought it might be fun and a challenge to do it with a lattice brace system. The cross section of the segments of the lattice are 3mm x 5mm at their biggest and taper down to almost nothing where they end just short of the kerfed linings. To reduce the size of the spruce ladder braces on my previous sopranos I started reinforcing them with a vertical laminated strip of carbon fibre and decided to continue with this approach in these tenors. Seeing as this whole project started with an appreciation of the look of a tailpiece I decided to custom make the ones for these ukes. The strings pass through holes in a mulga dowel which hooks into the chrome plated brass metal bit. I’m very happy with how they look and function. The two fixed bridge ukes have identical fan braces with a carbon fibre bridge patch. I’ve strung one of these with high G and the other with low G. Both floating bridge ukes are strung high G at this time. So, to the specs:
Soundboards and Necks: Spanish Cedar
Back and Sides: Blackwood
Fretboards, Bridges and Headstock Veneer: Mulga
Soundboard Radius: 25’ fixed bridge pair, 15’ floating bridge pair
Back Radius: 15’ for all 4 ukes
Scale Length 18”
Fretboard Profile: Flat
Tuners: Gotoh UPTL
Strings: Worth Browns
Finish: Miratone
And what do they sound like? The two fixed bridge ukes sound just like normal tenors but maybe a little bit brighter. They aren’t any louder than the other tenors that I have played. The fan braced floating bridge one has just as much volume as the fixed bridge ones and is a bit brighter again with a bit less sustain. The lattice braced one is a lot brighter again with even less sustain. It’s maybe 5% down the road to sounding like a banjo. And as to this floating bridge on a nylon string instrument not having enough bridge downforce to transfer the vibration energy discussion. I shaped and polished the soles of the bridges to follow the soundboard radius and they are really well squeezed into place. To move them around slightly to optimise the intonation I have to really push them hard.
cheers
Paul

The attachment 1.JPG is no longer available

The attachment 2.JPG is no longer available

[Paul Henneberry]

ad a couple more pics

The attachment 7.JPG is no longer available

8.JPG (231.29 KiB) Viewed 13114 times

[Jim]

I love the way you can make some direct comparisons. Which one ended up being the favourite?

[Mark McLean]

Hi Paul
These look great, and It is really cool that building in a batch has allowed for some controlled experimentation with different designs. This is really useful information. It sounds like the main influence of the floating bridge and tailpiece on sound is more attack/less sustain? That makes sense, and chimes with my recent experience making a bouzouki-style instrument with a floating bridge. The way that you described it as "part of the way down the road to being a banjo" is a good way to put it. This is not a bad thing - but different.
Can you describe a bit of the process for making your metal tailpieces (or is it on your blog)? I would be interested in trying that.

[Paul Henneberry]

Hi Jim and Mark
I think small batch production and the economies of scale it offers is great right up until I have to get out the sandpaper.

Favourite, umm - as happy as I am with the look of the exaggerated neck angle, floating bridge and tailpiece pair I think I'm happiest with the high G fixed bridge one so far. To my ear and as a uke player it just sounds best. I've never played an instrument other than a soprano uke so the low G thing is taking a bit of getting used to (which must seem weird to a community dominated by guitar makers). I wanted to limit the sustain of my ukes and get back to the plucky sound of the old ukes but these floating bridge ones have maybe gone a little bit too far in that direction. I might make another pair of lighter bridges and see how that affects the sound.

Tail pieces. I started this project with the intention of thoroughly documenting the whole process for my blog but after writing about the brace design and manufacturing and the binding process I dropped the ball. I regret not taking one picture of the tail piece making process. Each tail piece is made from 2 pieces of 0.9mm brass which I joined together with 40% silver solder. After the back shield shaped bit had the holes drilled and was filed to shape it was bent around a flange to match the 165mm radius of the butt end of the body. The top hook section was filed to the finished shape and the tangs were rolled to make the hooks. I thought I might have to make a complicated bending roller but I just managed to hand roll the brass around the edge of a piece of 5.5mm phenolic resin sheet after I had rounded an edge to a semicircle at the router table. I was lucky because I don't think I could have rolled the tangs without a better tool if the brass was any thicker. I made the mulga dowel on a metal lathe. Mulga is amazing, even when turning it down to 5mm it didn't bend at all when turned between the head stock and a live centre. Even over a length of 65mm, tough stuff.

So I'm left with 4 ukes and a very big box full of templates and custom made tooling. Wanting to get more value out of the box full of stuff I will probably start another batch of four to this same shape in a month or so. I made 4 of the cute tail pieces so I have two spare and will probably explore that design feature a bit more. Where would you guys go with this experiment if you were making another 4?
cheers
Paul

[Jim]

Maybe try an x braced one next?

[Mark McLean]

Or falcate

[Pat.Hawkins]

Hi Jim,
Beautiful - inspirational stuff!

I'm trying to make a tailpiece similar to the (stainless?) one in the photo.
(Using brass sheet around 1mm thick)

Could you share how you get such a neat curl around the front edge? ...........

and any other tips a beginner might use?

Cheers

[Paul Henneberry]

Hi Pat,
Thanks for the interest. Boy do I wish I had taken a couple of pictures as I was doing it! You will have to make do with a re-enactment and use your imagination. To correct a detail from above, I just put my callipers on some of the brass sheet that I used and it was in fact 1.2mm so you should be able to do this fine with your 1mm brass. And mine are made from brass and then chrome plated but more on that later. The first picture shows the two tools that I made to make the tailpieces. The second picture shows a detail of the very useful set of key steel clamps that I made for holding small pieces of metal while I file them. The third picture shows how the jaws slide apart on the ¼” tubes and sit on the roll pins in a vice. The fourth picture shows a detail of the edge of the strip of phenolic resin that the fingers were hand rolled around. The place of the brass tailpiece is taken by a stand in bit of card board and you can see how the brass was held in place with the backing board and little screws. I didn’t just bend each finger about the semicircle one at a time. I used the length of the phenolic resin strip as a lever and rolled all the fingers around at once while pressing the edge against the machined surface of a planer table. Pushing down hard while rolling meant I didn’t get any creases and that all of the insides of the fingers ended up exactly in line so that the mulga dowel had good contact and support. The fifth picture is a photo of my design sketch of the parts. I would be flattered if anybody wants to copy it, help youself.
When making small things out of metal that need to be accurate I always wipe the surface with marking blue first which is a kind of thin ink used in engineering shops. Marking out is done by scratching through the ink and it makes filing or machining the metal a lot easier because the lines are a lot brighter.
The two parts of the tailpiece were joined with 40% silver solder. It melts with a fine propane torch and runs into the joint well if the surfaces are clean and if a proper silver solder flux is used. If you are careful with the where the flux is applied that should be the only places that the solder runs on to. The tricky bit is getting the two parts to stay still and in place while you are soldering.
It was harder to get these things chrome plated than it was to make them. I consulted some car restoring neighbours about who I should go to here in Perth. They said that there was only a couple of chrome platers over here and that they were far too slow and expensive. They get their chroming done in Bali while they are holiday and recon the savings almost pay for the trip. I had made 4 tailpieces and I wanted a crisp and clean finish without the corners all buffered off by the chrome shop and I wasn’t sure I would get that in Bali. I ended up sending 2 of them up to Bali with my neighbours and 2 over to a place in Adelaide that had been recommended. The Bali ones cost $10 a pair and took a week. The Adelaide ones cost $60 a pair and took a month. The Aussie workmanship was definitely better but all 4 were perfectly OK. The ones fitted to the ukes in the pictures above were the ones chromed in Bali.
I hope that helps Pat. Have a go, what’s the worst that can happen.
And to correct something else I said above. I was asked about my favourite out of the 4 – I‘ve changed my mind, definitely the floating bridge with the fan bracing. These side sound ports are deceptive, you definitely get some nice feedback but I got a mate to play all 4 ukes at me and the floating bridge ones aren’t as bright and banjo like as I had thought, lots of volume and a generous amount of mid tones.