On with its neck!

In the end I did most of the neck shaping before I glued it onto the bowl - I just left the area around the joint over large and then shaped this after the glue had set.

I used Araldite for the neck joint and also added a dowel for additional strength. I did most of the shaping with a sanding drum on my multitool (running at a fairly low speed to avoid scorching).

Bowlback neck

Here is the start of the neck. It's made from maple, and is formed from a central core and some 'wings' glued on. The recessed section underneath where the fretboard will sit is to accomodate an extension of the belly. I noticed this feature in the mandolin I took to pieces and I presume that it will add strength to the neck - body joint.

I have been wondering whether to glue it on to the bowl and then do the shaping, or shape it first - I will probably go for the first option.

Status Update

I managed to 'rescue' the situation with the end cap of the bowlback mandolin by adding some edge pieces cut from some of the spare rib material. I bent these to fit on the iron (they needed to be bent in three dimensions!) and stuck them on with superglue. I broke lots of my early attempts. There were still a few gaps left so I filled these with araldite mixed with walnut wood dust. The result is OK, but not my finest work! All that because of a flawed design! I have now started on the neck.

I have also been making a bit of progress with the cittern. I fitted the bindings, and I think these look great (which is just as well as I want to sell this one when it's finished). I'm now starting on the fretboard.

A dog's breakfast

I have made a right dog's breakfast of the end cap... On the first attempt I made the end cap too thick (a little under 3mm). I could not get this to bend successfully (even after wetting the surface) so I made a new one, this time about 1.7mm thick. This bent well, but fitting it to the mandolin bowl was a nightmare. The problem stems from the fact that wood (or paper or anything non-rubbery) won't bend in two directions at the same time. This means that the surface to which the end cap gets glued has to curve like a cylinder, and not like the surface of a sphere! So the basic problem lies in the design of the mould (I will have to fix that for the next one). With a lot of clamps, too much glue, and quite a lot of swearing I did manage to get the end cap fitted - after a fasion. Once the glue is dry I will have to add some decorative bits to hide the gaps. Oh well, it's all part of the learning process.

Bowl complete

Well, the basic shape of the bowl is now complete and here it is, removed from the mould. Once I'm sure that I won't be needing to put it back onto the mould I will chisel off the extra bit that was glued to the inside front cap (with the screw holes in it). The next step it to fit the end cap which wraps around the front of the bowl. When this is done I will line the inside of the bowl with paper - I'm thinking of using tissue paper and a dark coloured cellulose dope (the stuff used to cover the wings of model aeroplanes).

Bowl Progress

I've just fitted the second of the two wide ribs that complete the bowl. These were much trickier than the narrow ones and even when bent as accurately as possible they seemed to twist out of shape when gluing them up - I think the the mould is at fault here and that the next mould needs to have this section at exactly right angles to the top. I will also add a removable section to the mould to give something to push against when fitting these last two ribs.

Luckily, I managed to get the untidy part of the joint to be at the front of the bowl where it will be covered by the end cap (which I'm going to fit next).

The thirteenth rib

We had a trip away last weekend, so there was no chance to spend any time in the workshop. However, this weekend I managed to do another couple of ribs on the bowlback. I am definitely getting better at the process, but I still find it tricky. The key seems to be getting a really accurate shape when bending the ribs, and then marking the sides to be shaped carefully with a thin flexible metal straight edge fixed to the bent rib with small spring clamps.

The other thing is the glue... I have taken to squeezing some Titebond onto a piece of polythene and then folding this in half. I then drag the thin stringer through the glue inside the polythene to coat both sides of it at once and then trap this glue soaked strip between the existing bowl and the new rib before hammering in the tacks.

Four more ribs to go!

Rib seven

The bowlback is making good progress, and I added ribs six and seven this weekend. My wife spotted it in my workshop last week and reckoned that it looked like a 'demented armadillo' so at least it has a name!

The mould needs some improvements for next time:

1.The end cramps slip off too easily, for example when I hammer in a tack, so I will have to devise a way to fix the head of the cramp inside the mould.

2. I think it would be better to shape the mould with flattened areas to acommodate the ribs (it is rounded in cross section at the moment).

3. my gluing up technique with Titebond is messy, so I could use a brush, or maybe try the hot melt hide glue stuff.

Meanwhile, I have put together a device to make the cutting of binding channels a bit easier. It is inspired by the one available from Stew Mac, which I think is really expensive! Mine was made from bits and pieces I already had, and seemed to work well on the cittern. I was especially pleased with the counterweight, which is the head of an old club hammer connected by wire over a cotton reel.

Bowlback - rib number two

I have now started on the ribs for the bowlback.

After bending the middle one to shape (dry) on the iron, I glued down the tip and the tail, and when the glue was set I shaped it with a chisel and then a file.

The next day I prepared a 'stringer' by bending a strip of sycamore veneer, and then bent the second rib to shape. After a bit of shaping (again with a chisel and a file) of one side of the second rib, this could be fitted in a fairly snug way to the first one with hand pressure. The stringer and the second rib were then glued into place (and at the tip and tail) and held in place with some carpet tacks and a rubber lugage 'bungee' while the glue set.

The next step will be to fit the third rib (on the opposite side to number two), and then to shape the outer edges of these ready for ribs four and five.

There are seventeen ribs in all, and two wider pieces at the top, as well as an end 'cap' and decorative side pieces. This will therefore take ages !

A few observations - First, I am using titebond glue, but I wonder if hide glue would be better. Secondly it's going to take a lot of practice to get any good at this and; Thirdly, I notice from the photos that I am a really untidy worker!

Stringers

I thought that I'd have a go at making a stringer today (the thin strips of pale wood between each of the ribs). I expected to find these quite tricky to make, but the process was surprisingly simple!

First I used a hacksaw to cut a groove in the top of my bending iron (actually the extension piece). The slot was deeper at the edges than the middle to make it curved at the bottom. I then cut some 3.5mm strips from a sheet of sycamore veneer (0.6mm thick) and dragged these through the slot once the bending iron was hot. As long as I worked with short movements, holding onto the strip as close to the iron as possible, it was straightforward to shape curves with different radii. Two of these practice bits are also shown in the photo. A light coating of moisture (applied with finger and thumb) speeded up the bending a bit.

When I make the stringers 'for real' I will probably prepare a set of strips and bend them as I need them.

Neck and ribs

It's always a big moment when the label gets glued in. I have counted back and decided that this cittern is instrument number eight, so I've added this as a serial number - this is probably a bit pretentious. The belly is already made, the braces are trimmed and I'm ready to glue it on.

Meanwhile, I have taken a piece of walnut and started to prepae the ribs for the bowlback. I cut 4.5mm slices with my bandsaw (with a fresh blade fitted) and then reduced them to a thickness of 2.7mm with my drum sander. Out of the 24 bits, a few are sapwood and very plain, but the rest have a nice dark colour and some attractive grain.

Mould

Here is the new mould, with the shaping finished, next to the original.

Bowlback mould

The mould is underway. Here are the first two bits (sycamore) in place - the rest builds up on either side and then gets carved to shape. I've just started the carving process and I'm remembering just how hard sycamore is! This step is going to take a while...

Cittern and bowlback mandolin

Well, it's been a month or so since I last posted a progress report - Easter has been mostly occupied with our new vegetable plot, but I have had a bit of time to push on with the cittern. The body is now complete and I'm ready to start fixing on the neck.

I'm also getting cracking on the bowlback mandolin project. I have 'dismantled' the one I bought on ebay (I think the cracked neck made it beyond repair anyway), and taken lots of photos and prepared some drawings. The detailed look at the old Neopolitan instrument was very informative - it was fun to imagine the 'production line' for these inexpensive litte instruments in the south of Italy at the turn of the last century. I have now started to prepare the mould for my own bowlback based on the technique used for lute making.

Finished!

Well... it's done. I had to fiddle about with the tuning, and in the end it seems best in fourths, to a', d', g' and c''. There's a bit of buzz on the open strings - it doesn't spoil the sound, but I wonder if it's originating in the nut. Here it is with my clumsy fingers playing it (bit of a sloppy recording on the computer microphone). It will meet its new owner, my sister, next weekend.

Tied Frets

The top pair of strings are still missing, but I have now had a go at tying the gut frets. This mostly went well, but I had a couple of breakages (actually the knots slipped and it's impossible to reuse the piece of gut) and I ran out of material! I had to use a length of nylon string as a temporary fix for the seventh fret.

The cittern was dusted off, and I made and fitted the braces to the back.

Broken Strings

The gittern is now almost finished, and only the tied gut frets remain to be fitted. I strung it up at my intended pitch (d', g', d'' & g'') but this was just too much of a stretch for the top pair of strings (0.33 mm carbons) and so... 'twang' followed by a small amount of blood! I have now lowered the pitch by a third to b, e', b', e'' and await the arrival of some replacement top strings (0.37mm).

The tone is clear and bright, with good sustain, and a bit louder than I had expected. The volume increased noticably as I 'fitted' the bridge (reducing its mass by more than half). I made the bridge from Macassar ebony as I like the colour (it looks good with the rosewood, and doesn't really need any oil finish) but I wonder if sycamore, being less dense, would have made it even louder. If I'm feeling adventurous I might try and post up a short MP3 (when the new strings are here and the frets have been put in place.

Four coats of Tru-oil

Four coats of Tru-oil so far. and probably a couple more still to go. The main remaining woodwork will be to make the bridge, but I don't want to make any dust at the moment so I'll probably tackle that job next weekend.

A few scratches have made it through the sanding process - I will have to take more time on this process on teh next instrument.

Getting Close

No picture today, but the gittern is now ready for 'finishing'. I'm going to use Tru-Oil, my favorite 'drying oil'. I have still to make the bridge and to do a final fit on the nut and the pegs, but after that it's just the strings to add!

Binding

I have made and fitted the bindings which I made out of an old 'orphan' guitar side (in Indian rosewood). The white section in the picture is bone, which the strings will wrap over.

I have also fitted the fretboard which is also Indian rosewood and tones in quite nicely. I was going to try and use authentic glues, but in the end there is a bit of everything in there: titebond, cascamite, araldite and superglue !

On with the soundboard

Here is the soundboard with the braces glued in position. I was guided by the positioning on a lute, but it's really just guesswork! I also had a go a some tap tuning (listening to the sound of the board when tapped with the end of a finger), and although the sound clearly changed as I removed wood from the braces, I was not not sure what I was aiming at...



Anyway, when I was happy with the tap-tone, I glued the soundboard onto the body.



I also tidied up the fretboard a bit, ready for gluing into place, and made some lengths of binding (rosewood) and bent them to shape on my bending iron.

The soundboard

Here is the soundboard with the rosette cut out. I followed the method in my lute book and I am reasonably satisfied with the outcome, although I think I might be needing some glasses soon!

I have made some tone bars from some nice quarter sawn Alaskan spruce (it's light as a feather) and glued the first three in place. I have put a very slight curve in the soundboard to help resist the downward pressure of the strings (although I think that this will be only modest with gut strings).

Finally, I have also started on the fretboard, by locating a lenght of rosewood in my 'woodpile'.

Rosette

Here is the design (I used a program called Kali to help make this).

I printed this out and stuck it on the reverse of the soundboard.I had thinned the wood to just over 1mm to make the cutting out easier.