# Finished! Making a ukulele



## profchris (5 Sep 2016)

A friend's daughter Jenna (aged 10) won a set of Tasmanian Blackwood in the raffle at a ukulele festival, and very generously offered it to me as a present! Heavy negotiation ensued, and eventually I beat her up to me building the set as a uke for her. I also promised progress reports, and as I'm posting them on a uke board I thought they might be of interest to other woodworkers if I reproduced them here. Uke making is a strange combination of precision luthiery and improvised bodging.

So, Jenna, I've made a start on the top and back. The wood is far too thick to make a ukulele, so I have to make it thinner. This picture shows your blackwood, and the thin bit is roughly how thick it needs to be.







Also top and back are each made of two pieces, so I need to glue them together before I start to make them thinner (which for some reason is called thicknessing!).

I need to get straight edges on both pieces to be glued, so I put them in a vice and get the edge to be joined roughly straight.






Then I take my very long plane:






And I use a cunning trick learnt from a friend (who learnt it from someone else) and clamp the plane upside down in the vice. Now I slide the two pieces across the plane to produce a perfect (I hope) joint.






The reason for doing both at the same time is that, even if I don't hold the wood absolutely upright, this will give me matching angles so that there are no gaps. We will find out once I start thicknessing!


----------



## profchris (5 Sep 2016)

Now I have to glue the pieces together. This is the way I do it.

First, I use masking tape to stick them together, as on the right. Then I turn the joined pieces over on a flat board and put a pencil under the join to make a kind of tent. Bang nails in along both sides.






If I apply glue along the join and press down, you can see that the nails push the two pieces together all along the joint.






So I did that ...






and once the glue has dried I will have turned four pieces of wood into two pieces, each big enough for a top or a back. I won't decide which is which until I've thicknessed them, when I'll decide which looks best for which role.

You might be thinking that your ukulele is going to look a bit boring, because unfinished wood is very dull. So, this should give you an idea of what to expect:






Much prettier!


----------



## profchris (5 Sep 2016)

A note on edge joining thin plates (these were around 4mm):

1. I've used hot hide glue to join these plates for two reasons. First, it's the best candidate to give me an invisible glue line even if my joint is not absolutely perfect. Second, if I discover that I've made a mistake in jointing I can simply apply heat and moisture and the glue will release, and I can reglue without cleaning off the old glue because fresh glue reactivates the old.

2. Like most plates, these were vertical grain at one side and a little less vertical at the other (that's how trees grow). I've chosen to joint the most vertical grain, because that will give me a stiffer plate. Stiffer means I can make it thinner, and thus get more volume because a thin plate is easier for the string's vibration to move as it has less mass. But if the figure in the wood had looked markedly better the other way I would have gone with that, and built accordingly.


----------



## profchris (5 Sep 2016)

Thicknessing plates is always the hardest part of the job, and is really daunting for first time builders. Glueing together was comparatively easy! So I thought I'd explain how I do it, in case it helps others.

The problem is that this Blackwood is about 4mm thick (which is a good thing, because thinner would give me less room to make mistakes when glueing up). I need them to be less than 2mm.

I begin by planing, using my Stanley no 3 (£20 or so from eBay, less from a car boot sale). The first problem with planing is runout.

Runout is where the grain, looked at from the side edge of the plate, is at a slight angle. There is always some runout, and woods with figure like this Blackwood have quasi-random runout because the figure is caused by wavy grain. No problem you cry - don't plane into the runout like this > \\\\\\\\ (exaggerated, but you get the idea), because the blade will dig into the slanted ends of the grain and tear lumps out (called, yes, tearout). Plane the other way: >///////

Yes, but ... Most tops and backs are bookmatched. Two consecutive slices are taken from the wood, and then opened out like a book and joined where the spine would be. This looks excellent because the two halves are mirror images and so you can't see a disconnect where they join (if you get a good joint, see previous post).

But bookmatching means the runout in each half goes in the opposite direction. I cope with this by planing one half, then turning the plate and planing the other half. If the wood is well-behaved (and this wood was very cooperative) then I can get a nice, flat surface on one side. Good start.

Even so tearout is a risk. To reduce this when planing with the grain I get my blade as sharp as possible, and I set the cap iron as close to the edge as I can manage without covering the edge. Setting the cap iron this close means you can't take shavings any thicker than the sliver of blade, but it does make it far less likely that you'll get tearout.


----------



## profchris (5 Sep 2016)

But the plate is hardly any thinner after this work. I need to start work on the other side, but planing off thin shavings will take forever. And trying to take thick shavings will cause tearout. Dilemma!

The solution is to set my cap iron for thicker shavings, and then plane at 45 degrees to the grain direction, like this:






On figured wood you'll get a little tearout (I did), but not so deep that you ruin the plate. So do this, turning the wood regularly, until you reckon you'll be a little above final thickness once any tearout has been smoothed away.

Now things get more delicate, because the plate os around 2mm thick and is flexible and fragile. I might try planing with the grain as above, resetting my cap iron, but this is risky. I'm putting quite a bit of leverage on the wood as I plane, because of where the clamps have to be to hold it down, and could split it. Or I might cause more tearout.

The simple solution is to switch to a cabinet scraper (plenty of instructions for use and sharpening online, try all the sharpening methods until you find one that works for you). You bend this tool slightly (fingers on edge, thumbs in centre) and then push it across the wood. If it's sharp you get really fine shavings (compare the fluffy scraper shavings here with the much more solid plane shavings).






This is slow work, and more effortful than you'd expect, but is highly controllable.


----------



## profchris (5 Sep 2016)

But I have a better device:






I took a punt on a £15 box of wooden planes because I saw this in it and got lucky. It has a toothed blade:






(this is a veneering blade with lots of grooves, for large work fewer but deeper grooves makes it work faster)

In effect, I'm scraping twenty tiny chisels across the wood, and if I work at 45 degrees to the grain it produces what looks like ultra coarse sanding dust. Five minutes work reduced the plate to very nearly final thickness. Quick but very controllable, and ensures I don't accidentally thin some places more than others.

Of course this toothed blade leaves grooves in the wood, but a minute or two with cabinet scraper removes them. Or they could be sanded out. In some old instruments you can still see the grooves inside, because there is no structural reason to remove them except where you want to glue.

The plate is now just under 2mm and still a bit too thick, but I'll leave final thicknessing until I start making the body - if I ding or scratch this, I have some leeway to scrape away the damage.

Now to repeat this for the other top/bottom plate and for the two sides plates. So no more until that is done.


----------



## deema (5 Sep 2016)

Great build thread, loving it


----------



## AJB Temple (5 Sep 2016)

Super thread. I have never made a uke, just guitars. Do ukes ever have a belly in the back or are they dead flat?


----------



## profchris (5 Sep 2016)

AJB Temple":2e6z4ka7 said:


> Super thread. I have never made a uke, just guitars. Do ukes ever have a belly in the back or are they dead flat?



Many are dead flat, but I like an aggressive belly - in due course!


----------



## profchris (5 Sep 2016)

I started this a couple of weeks ago, so there is more to come before I revert to real-time building.

Next was thicknessing the sides but they are trickier. With top and back I could plane one half, clamping at the other, and then flip the plate and plane the other half. This works because they are wide enough to clamp one side and plane the other half. Sides are too narrow for that.

So I decided to pause and convert one of my woodie smoother planes into a scrub plane. This needs a wide mouth, which the plane already had, and the cutting edge of the blade is ground into a very aggressive arc. So I did that (takes a lot of grinding on a thick blade) and tried it out on scrap first. Success!

So here is the blade (in the plane), on top of a side in progress, with a pile of shavings next to it. You will see that they are not really shavings, but instead large, long chips. In effect, the plane scoops gouges in the wood, taking it down very fast. I got this side down to near final thickness in about 5 minutes, most of which was spent moving the clamps to reach each part.






Tips on use, learnt the hard way (destroyed scrap wood bears witness to this).

1. Set the depth of cut very carefully. Once the blade starts to scuff the surface it only needs to be advanced a little further to produce suitably deep gouges. Too far and it digs in enough to split thin wood.

2. Plane at 45 degrees, NOT in the direction of the grain. Planing with the grain tears out large lumps. But 45 degree planing is remarkably controllable, and although the final surface is rough it will work down smooth very quickly (I'll use my toothed plane and a scraper for that).

3. Work sides in three sections - clamp at middle and one end, plane other end; reverse; clamp both ends and plane middle.

I'm quite pleased with myself! Final thicknessing is enjoyable, as I feel out the wood to decide whether I'm at the right point yet. Getting it to that point is just grunt work, and my scrub plane removes 90% of the grunt.

Then I made my life a bit easier when I remembered I had a non-toothed iron which would fit my toothed veneer plane. Swapping the irons turns it into a scraper plane, which does most of the scraping work and leaves me to finish off with the hand cabinet scraper.

Using this lot, it took about 20 mins a side to get them down to near-final thickness.

So at this point I have all the plates (top, back and sides) close to what I want. I'll do the final thicknessing, using only a cabinet scraper, immediately before I start to build them into the body. Why? Knocks/bumps/gouges. I can take any of these out during final thicknessing.

Readers (if any are left) will have noted my obsession with tearout. This is because these plates are scary thin - the top and back will end up around 1.5 mm, and the sides only about 1.2 mm. Usually I'd go thicker (say 1.8 and 1.5) but this wood is particularly stiff longitudinally. You can see that even 0.2 mm of tearout on the last pass of the plane would be a problem for me!


----------



## bucephalus (5 Sep 2016)

Great WIP, really interesting and informative.


----------



## profchris (5 Sep 2016)

Next I need a neck.

The neck blank in the kit is very nice, but it's not cut for using a Spanish Heel, and that's what I want to do (explained later). So I'll use that for some other project and substitute a similar neck from my own stock.

I glued up two pieces of mahogany (recycled shelf) to make a blank about 2 1/4 inches square and about 13 inches long. I did this to get favourable grain orientation for stability and ease of carving, and also because it makes a nice stiff neck if you do it right (fingers crossed there!). Plane it square on all four sides.

[Digression on grain orientation: Ideally every piece of wood in a uke or guitar will have vertical grain. The reasons will be explained later.

For necks, horizontal grain can be good too. But diagonal grain is not ideal - OK for ukes because they are small, but for a guitar there is the risk the neck will twist.

One way to deal with this which enables you to use wood with grain on the diagonal is to laminate two pieces with the grain running in opposite directions: \\\\//// or ////\\\\. This produces a very stable neck.]

Then I marked out the underside and top of the peghead on one of the sides and cut it out on my birthday bandsaw. I've cut less close to the lines than I might because I'm still learning how to use this bandsaw, but it's so much better than my old one! 






I could do this with hand tools but it's hard work because the blank is so thick, and I can be more accurate with the bandsaw (unless I go really slow with hand tools).

Then I mark out the vertical shape of the neck:






If you look at the horizontal line just above the heel, that's where the neck will join the body. I've left quite a lot of blank to the right of that. This is because Spanish Heel construction doesn't have a separate neck block - slots are cut in the neck into which the sides fit. So I needed a longer blank to allow this.

Once cut out, we have something which is clearly on its way to being a neck. So the next instalment will be neck carving.


----------



## profchris (5 Sep 2016)

To rough carve the neck I start by dividing the back into thirds, and marking a line on the side 1/3 up from the surface of the neck:






Then I got out my new rasps - less than £15 for all three direct from China, and they're really sharp. [Checked up pricing recently and they're over £20 a set now on Aliexpress, but still worth it I think]






Five minutes later the neck looks like this:






Now I just flatten off the ridges between the facets I've created to get this, which has NINE (I originally wrote seven, fool!) facets:






A rasp isn't essential - I used to do this with chisel and cabinet scraper. Some use spokeshaves, but this soprano neck only has about 5 inches of shaft to carve.

At this stage it's remarkably close to the final shape, so I can hold a fingerboard on the neck surface and feel how the neck would work. It's currently too deep front to back, particularly as Jenna has small hands, so I'll make it thinner when I come to the final shaping.


----------



## profchris (5 Sep 2016)

Up to now I haven't really flattened the top surface of the neck, just got it close. The reason for this is that as I carve the neck there will be some internal stresses in the wood which are likely to make it move about a little. Any flat surface I make won't be flat enough any more.

But now that I've removed the bulk of the wood, I can flatten the top surface. I use a really big plane for this, almost twice as long as the neck (I could use a shorter one, but as I have the big one and it is easier to use for this, why not?).






I also flatten the surface of the peghead and bring it in line with the neck surface. This means I can measure from the new surface to get the back of the peghead to the right thickness (that happens later).

Now I need to mark out and cut slots at the heel end, into which the sides will fit (this is the Spanish Heel part). I leave this until now because, as I plane the neck surface it gets longer (at the peghead end), and as I plane the peghead it gets shorter again. I want the body to join at the 12th fret, but I can't measure that until now because of those changes.






I cut the slots with another of my birthday presents, a Pax 1776 Dovetail Saw from Thomas Flynn. This is a serious piece of kit, made by artisans in Sheffield's last traditional saw works and not stamped out on a production line but hand worked. It's like being a top flight surgeon when I use it! And at ukulele making workload it has at least 200 years of life in it, so aspiring legatees should start being nice to me right now.

The final process for today was to cut the heel sides roughly to shape on the bandsaw and then fair them into the sides with a block plane.






The end of the neck beyond the slots is far bigger than I need, but I won't cut the excess off until final shaping is complete. This gives me somewhere to clamp the neck while working on it, without worrying about dents and dings.

Next, final neck shaping.


----------



## profchris (5 Sep 2016)

My next process is to shape the heel. With my new rasps this is vastly easier!

I use the round side of the rasp to establish a curve on the imaginary line from where the neck joins the top (the edge of my slot for the sides) round that heel and joining up at the equivalent place on the opposite side.











As you can see, I don't take it right back into the angle where neck meets top, though you could.

Then smooth away the hump between my new curve and the neck shaft (this picture is close but not completely there yet), again using the rasp very carefully so as not to put gouges into the neck shaft.






Then round over the thinnest part of the heel and blend that into the curve to get my rough heel shape.






From here I could work it to a fancy shape (stiletto heel?), but this looks pretty good, so I simply work carefully to remove lumps and bumps until it all curves smoothly together. If I wanted to make the heel smaller I wouldn't tough the neck block part, beyond the slots.

The next stage is to round over the neck shaft. I remove some of the remaining ridges (I use a cabinet scraper but sanding would work, though slower), and then use a strip of coarse sandpaper like a shoe shine. Keep working this until you can see that the whole of the back of the neck shaft is being sanded, and you will have a nice smooth round to it.






But, DO NOT sand all the way to the edge of where the fretboard will be - leave a 1-2 mm strip to be smoothed in via hand sanding, or you could sand away part of that edge!

After this there will be more blending at the heel, because you've lowered the back of the neck a little, and some blending into the headstock. No pictures because it's fairly obvious what needs to be done. Use scraper, rasp, chisel, knife, sandpaper - whatever you feel comfortable with. At this stage if you accidentally remove too much wood you either have to reshape the neck or live with the dent, so use something you can control easily.

And then sanding and more sanding, always going with the grain and switching to a higher grit until you're happy you've removed all the sanding marks. You have to back the sandpaper with a block, or your finger pressure can sand in dents. My block is a wine cork cut lengthways, which is a nice size for a soprano neck.

When you think you have sanded it perfectly smooth, splash some white spirit (mineral spirits in the US) on a paper towel and wipe it over your sanded surface. 






See all those marks you still haven't sanded out? So keep going until you're content to live with the result!

By the look of it this neck will be pleasantly stripy when it's finished.


----------



## Harbo (5 Sep 2016)

Watching with interest

Rod


----------



## custard (5 Sep 2016)

This is riveting reading!

=D> 

How many hours work?


----------



## Woodmonkey (5 Sep 2016)

Nice thread, making a uke is definitely on my round tuit list


----------



## Biliphuster (5 Sep 2016)

Looking forward to seeing how the thin sides are joined to the thin top with enough strength to hold up the stresses of playing.

Very informative so far.


----------



## profchris (5 Sep 2016)

custard":3ucomd39 said:


> This is riveting reading!
> 
> =D>
> 
> How many hours work?



Hard to say - I do 15-60 mins at time when I have free moments. 

I'd guess we're about 6 hours in so far, but if I used a drum sander and spindle sander I could be this far in about 2 hours, much of which is measuring (so with good templates, maybe 1.5 hours). 

I usually estimate 40-50 hours to completion, all hand tools except the bandsaw. Power tools and spray finishing could halve that. 

BTW I owe you a PM - got distracted!


----------



## AJB Temple (6 Sep 2016)

I was interested in your home made plane scraper. Very interesting technique and not one I have used. 
Presumably a uke neck never needs a truss bar because it is short and presumably with four strings the tension is a good deal less too.


----------



## Kalimna (6 Sep 2016)

Most excellent thread - thoroughly enjoying the explanation of processes along with the underlying reasons for the build 

AJB - I've built only a couple of ukes and neither of mine had a truss rod (though did use a bolt-on neck joint), and my research at the time led me to believe that whilst truss rods are generally considered unnecessary, for the reasons you state, some builders install carbon fibre rods for added stiffness.

I am looking forward to this ukes completion, and the gentle kick in the bum I need to get back to building (I keep finding excuses not to!) 

Cheers,
Adam


----------



## bugbear (6 Sep 2016)

AJB Temple":3oe7ttto said:


> I was interested in your home made plane scraper.



If you mean the toothing plane, it (was) a standard factory product.

This article popularised them (in some circles)

https://anthonyhaycabinetmaker.wordpres ... -our-time/

Although Dunbar's book spent a good deal of time on them, a good deal earlier.

Very much a tool of veneering and luthiery.

(more on the blades;

toothing-a-blade-t62336.html?hilit=toothing

Paul Chapman's mega thread on toothing blades in "normal" planes.

toothed-blades-for-bevel-down-planes-t25170.html

)

BugBear


----------



## profchris (6 Sep 2016)

No truss rod required for nylon strings - even classical guitars don't have 'em. 

The non-toothed iron in the woodie was a sudden brainwave, inspired by my Stanley no 80 scraper plane which I don't use any more. The problem with the Stanley is the handles - on these tiny plates they foul the clamps, whilst the woodie is narrower and slides past the clamps. 

Think I might attempt a Krenov style body so I can keep both set up rather than swapping blades.


----------



## thetyreman (7 Sep 2016)

this is an excellent thread, looking forward to seeing the end result, it looks great so far.


----------



## n0legs (7 Sep 2016)

Brilliant  
One of the most interesting WIP's we've had =D>


----------



## profchris (10 Sep 2016)

I think (I'm not a very systematic builder) that the last step before starting to put things together is to sort out the fretboard. If you were attaching the neck separately, as a bolt-on, dovetail, etc, you could leave the fretboard until later. But with Spanish Heel construction the neck gets attached to the body very early, as we will see. It's much easier to shape the fretboard to the neck if the neck is not attached. So, I sort out the fretboard now.

I've selected a board which is a bit stripy, and I think it will go nicely with the neck and the body. The board is thicknessed to my desired dimensions, in this case 3mm.

Next I plane a straight edge along one side, and I'll do all my marking out from that. With a scalpel against a set square I mark out the end of the board and my zero fret position (you can just see two faint lines to the L of the ruler), mark a centre line, and then tape my ruler down along the centre line. 

[For non-luthiers, usually strings terminate in what is called the nut, a piece of bone, plastic or ebony which sits at the peghead end of the fingerboard. The slots in the nut dictate the string spacing, and the height of the nut dictates the string height at the lower frets. But it's possible to replace the nut with another fret, called the zero fret (in which case you need something to space the strings, and that looks very like a nut). The zero fret guarantees that you get the action height right, and is (possibly) easier to build. Whether a zero fret is a good thing or not is somewhat a religious issue, though not as bad as the sharpening wars. But I use one.]












Then I calculate my fret positions and mark them out by nicking the centre line with my scalpel at each point (this is 330mm scale, or 13 inches, and has 12 frets). Once I've done that I can use my set square on the planed edge of the board to mark out the fret positions - place scalpel back in each nick, slide set square up to the blade, score line.






Once that is done I make shallow cuts along each line using my fretting saw (in this case a Zona Thick Kerf Dovetail Saw, about £12 delivered online). I nick one end of the line with my scalpel, place the saw blade in the nick, slide the set square up to the saw (checking the square lies along the line) and then gently run the saw along the set square for a few strokes. I only want to go down about 1mm, enough so that when I sand the board later I can still see where the fret slots are supposed to be.






(The important thing here is that the saw must be sharp, and you don't press down, just let it slide and cut. Go slowly and you won't jump about and scar the board. If your saw is blunt or you press, there will probably be a mess.)

Finally I drill small holes at the 5th and 10th frets, where the fret markers will go (I drilled the 7th while I was at it), and use these to screw the board to the neck. Measure up the centre line of the board from the 12th fret to the 5th fret hole, and then measure the same distance from the 12th fret/body join line of the neck - that's where the 5th fret screw goes. If you mark your centre line under the board as well, you can line that up at the heel end of the neck and tighten the 10th fret screw. 






The board is now in the right position on the neck, and I can mark and trim away the overhang. I'll leave the board attached during final sanding of the neck, so as to get a really good fit when I eventually glue it on (much later).


----------



## profchris (10 Sep 2016)

Now it's nearly time to start sticking stuff together, rather than making it smaller. But first I need to get the soundboard down to its final thickness. I'm finding my wooden smoother plane is working very well on this wood - note the wispy shavings which fill it - and the cabinet scraper deals with the final fraction of a millimetre.






This Tasmanian Blackwood is amazingly stiff! The soundboard is only about 1.5mm thick, and it still feels on the stiff side. But if I make it too thin, the uke will sound empty and twangy like a banjo.

Fortunately, because I've chosen Spanish Heel construction I can't finish (i.e. make shiny) the uke until it's completely built. This means I can put strings on it before I finish it and see how it sounds. At that point I can sand or scrape a little more off the face of the soundboard until I'm happy with the sound.

Next I mark out the shape of the body on the inside of the soundboard and cut out the sound hole. This requires a high-tech tool - a scrap of thin ply with a hole in it, a drill and a scalpel. 






Drill through the soundboard at the centre of the sound hole, making sure the drill goes deep into the wood block you've put underneath. Stab scalpel through ply at required radius, and gently score round your circle. Keep going to deepen the cut. After a bit, turn over the sound board and cut from the other side. A few minutes later you can pop out the circle of wood, and then tidy up by sanding (my half wine bottle cork is useful here, using the round side as my sanding block).

With Spanish Heel construction the neck is attached to the soundboard as the first major building step. So I cut off the extra from the neck block, and then chisel a step in it which is the same depth as the soundboard is thick. This is where the soundboard will glue to the neck.






But before I glue it on it will be easiest if I glue the bracing and bridge patch on the underside of the soundboard. Spruce is the best bracing material, and I have several chunks of grand piano soundboard. 






The grain in these is not quite vertical, which is strongest, but if I split off a chunk then the split will follow the grain direction, and I can then plane up the bracing so the grain orientation is as I want it.






And after planing, and finding a scrap of spruce for the bridge patch, I have these:






So here is my kit of parts to glue up, placed as they will fit together. Once I've glued them together I can show you all how I plan to build up the uke from face down, on a board.


----------



## profchris (11 Sep 2016)

Assembly begins!

Brace and bridge plate being glued on:






Most sopranos have two braces, one above and one below the sound hole, to stop the uke gradually folding up into its own sound hole. But the narrow waist on this shape, copied from a Dias uke of the 1890s, makes the upper bout stiff enough not to need the upper brace, so I leave it out - the lighter the better for me.

I wasn't sure whether to glue up (this was a few days ago) because the forecast humidity was on the high side, around 70%. The top expands sideways with humidity, and shrinks back when the humidity goes down. So if I glue these parts on in high humidity, as the top shrinks the brace and bridge plate will resist and the whole thing could cup or twist. But I put the heating on in the workshop and checked my home made humidity meter - two strips of veneer glued up with the grain at 90 degrees, so it bends one way if damp, the other if dry. It was bending the right way, suggesting humidity indoors of about 50 %, so glueing could happen. 

The neck is glued on, making sure the centre line of the top lines up with the centre line of the neck:






And then - loads of blocks around the edge of the shape I've drawn on my soundboard.






The reason for this is that I'm not using a mould. I will bend the sides to shape, and then trim them until they fit within the blocks. If I do this right, the blocks will make sure the body shape remains correct. Once the uke is complete I trim off the overhang together with the blocks.

As previously mentioned, I often use superglue for these block. But the Blackwood is very porous, as I discovered when I damped it with White Spirit to check the likely effect under finish, so superglue would wick through. Thus all my glueing will be done with hot hide glue. This has the reputation of being tricky, but I find it very easy to use. It has some big advantages, and we'll see one in particular when the back goes on (or maybe even earlier).

Now I attach the whole assembly to my building board, which is just a thick slab of flat MDF cut a bit bigger, and with slots for the string (yes, string might be involved).






The board keeps the top flat, and the neck in the right position, and I build up from there. To ensure the top stays flat I put a few screws around its edge so that their heads hold the top down, and screw a block across the sound hole to keep it flat there. Note to self - remove that block before gluing on the back!






And the board is used to set in my desired neck angle. This is ludicrously easy to work out, without any reference to angles at all. It goes like this:

I want the top of my saddle to be about 10mm above the top. The fretboard is 3mm thick, plus about 0.5mm for frets, so I need an extra 6.5 mm. To get 2.5mm string height over the 12th fret I need 5mm above the fretboard plane at the saddle, i.e. twice the 12th fret height, so that leave me short 1.5mm.

But the neck can be envisaged as a see saw, with the 12th fret as its mid-point. So if I need 1.5mm more at the saddle, I need -1.5mm at the nut (or zero fret in my case). I can get that by putting a 1.5mm spacer under the neck at the zero fret position and then taping down the neck.






This is such a small spacer that I didn't bother adjusting the angle at which I glued the neck on to the top. But if I'd needed a big spacer I'd have attached the top to the neck at an appropriate angle (put spacer under neck, plane top of the neck block portion until it lies flat on the board, then cut down from that to the thickness of the top).

And here it all is, locked in the right place. So long as I keep it on the board, my neck angle and alignment of neck with body will remain unchanged, even if I build the body in a completely cack-handed fashion.






So, on to side bending. But the sides are still too thick, so some final thicknessing first (no pics of that, it's the same as thicknessing the top).


----------



## profchris (11 Sep 2016)

The scary part!

Not because bending sides is inherently difficult though. The scariness is because you never know how that piece of wood is going to behave until you try to bend it - some cooperates nicely, others might crease, fold or even break. And I've never bent Tasmanian Blackwood before.

However, it's an acacia like koa, and koa usually bends very easily, so we will hope.

Usefully the sides supplied are wider than I need, so I cut off the surplus and bend a piece of that. It needs to be hotter than koa, and requires quite a bit of steam, but then bends easily. So I approach the actual sides with a little more confidence.

One point - if you buy in a set of wood then the sides will probably be book matched - these are. If so, you need to bend them so as to match up the grain pattern on each side, otherwise it will look odd at the tail where the sides meet. And I plane the edges which will join to the top, so that I have a straight edge to judge my bending against.

Here is the main piece of bending kit, a hot pipe.






The pipe was the outside tube of a trailer jockey wheel, and I drilled and bent tabs on it so that I could bolt it to a slab of MDF. The heat comes from a £10 heat gun which has two settings - hot and really hot. You can use a gas torch, which I did at first, but naked flames and wood shavings don't mix comfortably icon_eek.gif 

A piece of damp/wet rag sits on the pipe, to provide steam which helps get the heat into the wood quickly. Some wood likes to be bent fairly dry, but this wood wants plenty of steam, so I regularly pour more water on the rag.

I start with the waist, whose position I've marked with pencil. Place the side on the pipe, keeping the planed side parallel with the MDF plate. Rock it back and forth a little with gentle pressure either side until you feel it start to give. Then persuade it into the curve you want - hint, you need your fingers close to the pipe for a steep curve, further away for a shallow curve. It's a question of feel, but if you're forcing it then you're pressing too hard. If it won't bend it's too thick - stop, thin the wood some more, and try again.

Once bent I check it against my template (or I could use the shape I drew on the inside of the top).






Once the waist is OK, carry on and bend the upper and lower bout.






If you're bending just on the pipe, carry on from here until the bend matches the template. It probably takes me 30 minutes to bend the first side, and 10 minutes to bend the second because I now have a better feel for the wood and so can go quicker.

But I have a light bulb bender I made a few years ago. It never really got hot enough with light bulbs, but I can use it to complete my bending.






The part-bent sides are gently clamped in, and heat from the heat gun is applied to the aluminium strip (recycled from a caravan). Check temperature with fingers regularly - hot enough to be painful if I press, but not enough to scorch the wood. Then I gently tighten the wing nuts, stopping if I feel any real resistance and applying more heat. Once the wood is held down to the bender, leave to cool for a couple of hours.

Et voila - bent sides!


----------



## Woodmonkey (11 Sep 2016)

Loving this thread, really interesting stuff. One question, to get the angle of the neck did you clamp it to the board with the spacer while the glue was still wet on the neck joint?


----------



## profchris (11 Sep 2016)

Woodmonkey":34rxcyiq said:


> Loving this thread, really interesting stuff. One question, to get the angle of the neck did you clamp it to the board with the spacer while the glue was still wet on the neck joint?



No, I let the glue dry first. Getting the neck and soundboard aligned properly is crucial to it playing right, so I wouldn't risk the joint moving. 

Notionally this means that the neck join is raised 0.75mm from my building board, but the top is bendy so it's nearer 0.25 mm. That's small enough to get lost in the wider inaccuracies of freehand building!

And we will, in due course see me rethink the neck angle.


----------



## Woodmonkey (12 Sep 2016)

Maybe (probably) I'm being dim, but I can't see how clamping it on an angle after you've already glued the joint will acheive anything, surely as soon as you remove it from the board it will revert to whatever angle you glued it at?


----------



## profchris (12 Sep 2016)

Woodmonkey":2pns0u1c said:


> Maybe (probably) I'm being dim, but I can't see how clamping it on an angle after you've already glued the joint will acheive anything, surely as soon as you remove it from the board it will revert to whatever angle you glued it at?



No, no, nooo! Once I glue the back on it locks the geometry in place. The back is glued to the heel, so the neck can't rotate forwards.

Cunning, huh!


----------



## Woodmonkey (12 Sep 2016)

Aaaah! Got it...


----------



## profchris (12 Sep 2016)

I trimmed the sides to fit, cutting them a little over-size at first and then trimming from whichever end seemed best until they fit:






Now the sides need to be attached at the tail using a block of something appropriate - I have some mahogany here.






If you want a perfect seam, this is the time to get that right. I haven't bothered too much as you can see, though this is pretty close.






This is because I will insert an end graft - a triangular piece taken from an offcut from the sides (though you could use contrasting wood, add purfling, etc) which runs at 90 degrees to the grain of the sides. I cut about half-way through the sides and chisel out the waste.






Then I trim my graft to fit and glue it in. 






Once the glue is dry I can shave it back roughly to the level of the sides, and finish that process once the uke is built.

But, Oh Calamity! It was sticky and humid that day, and the sides have sprung back a ludicrous amount. I don't want to force them in, because that will probably distort the final shape.






Fortunately hot hide glue stands up well to dry heat, so I'm going to attempt to restore the shape on the hot pipe. Worst case is that the tail joint releases, in which case I will just have to re-do it and probably cut a slightly larger end graft.


----------



## profchris (12 Sep 2016)

Now, I could keep you all in suspense, as I had to do on the uke forum where I started this build description. The previous post was last Tuesday, and Wednesday to Friday I was away speaking at conferences. The malformed sides hung over all of us like the Sword of Damocles.

But on Friday evening I was home and firing up the hot pipe. This time I bent dry and hot, and the sides are now back in shape and the tail block glue joint held.

Phew!


----------



## profchris (12 Sep 2016)

So over the weekend I began attaching the sides to the top.

Because the top will be bound there is no particular need to glue the edge of the sides to the top, because that join will be cut away when I cut the binding channel. However, the tail block _does_ need to be glued, so I start there.

The sides are not quite symmetrical, so I have to spring them slightly into the shape I want. Here I'm using a clamp to pull the RH side (as we look at it, LH side when playing) of the lower bout to the right place. I don't clamp on my little blocks because they are only glued to the soundboard, which is thin, so I've nailed an additional block to the MDF as a clamping place.






Once I've lined up the tail block with the centre line of the top I can glue and clamp it.






Then I work up towards the neck - lift sides slightly, a dab of glue and clamp to hold them in the right place, and then fit linings. 1.5mm plywood makes very good linings, particularly as in one direction it bends easily just under finger pressure. So I cut a strip the same height as the bindings* and glue it to sides and top. I've made clamps to hold the linings out of a stick of scrap wood and an elastic band.






*Important note: The binding channel will cut away the sides, so I need the lining to extend further than the amount I intend to cut away. I plan to install the binding so it stands about 1mm taller than the top, and the top is about 1.5mm thick. This means my linings will extend 2.5mm beyond what I'm going to cut away. I reckon that's enough, because once the binding is glued in the structural strength of the top/side join will be restored. But for safety, someone who hasn't cut a few binding channels might want to make the lining slightly taller, in case the binding channel is accidentally cut too deep (if you do that you add a purfling line under the binding to hide the mistake!).


----------



## profchris (12 Sep 2016)

Next I make sure the upper bout is in the right position - if you need to spread the sides, bamboo skewers pressing against bits of wine corks are very useful.






Before glueing the upper bout to the top I need to fix the sides to the neck. This is the cunning part about Spanish Heel construction.

I cut six small spruce wedges. They don't have to be spruce, but softish wood is probably best.






Then I tap them into the join between neck and sides, making sure the sides are flush with the top (an occasional tap with the hammer does this). You can't get a hammer in there, so I just put the shaft of a stout screwdriver against the end of the wedge and tap on that until the wedge goes home (thus the mashed up ends of the wedges). Three per side is plenty.






Normally I'd dribble in a little CA glue to stop the wedges moving, but because the top is so porous I dribble in some hide glue instead. The glue is to stop the wedge moving - it's the wedge which holds the sides against the neck.

And the result - a pretty good neck/side join. If I'd angled the slot a fraction more it could have been even better.






You could leave the wedges with rough ends, but as I'm letting you look inside I take a couple of minutes with a chisel to trim off the excess.






Now complete the linings and, when the glue is all dry, we can put the back on. I forgot to say that if using hide glue, once the lining is clamped in place you should warm it with your hair drier/heat gun to liquify the glue, then press the linings down with a stick.






IMPORTANT - this final stage of closing the box has to be carried out in low humidity (see previous comments about humidity and cracking).

And second thoughts - spruce is a bit soft for this purpose, whilst oak (which I tried first) is too hard. The wedges should deform as they go in, but still put pressure to hold the sides in place. I suspect mahogany is best - will make a mental note for next time.


----------



## profchris (14 Sep 2016)

Before the back goes on I need to shape the sides and glue in linings.

I like an aggressive curve to the back of a soprano. It looks good, and I also think it improves the volume and produces a fuller tone. But whether this is true or not I have no idea, though note that Martin and the Hawaiian makers all curve their backs.

To produce the curve I've created a sanding trough. A thick chunk of MDF, with a thin (6mm piece) screwed to it along the centre line, and then battens pushed under at either end. This takes on its own curve.






I use this to sand the sides so that they curve fore and aft. The heel and tail are 2 inches tall, and the sides are 2 1/4 inches. With a chisel I remove material from the middle of each bout to the neck heel or tail respectively, to avoid having to sand that away. Then I start sanding. You can clamp the uke body on its board to the bench and move the trough, or clamp the trough and move the uke. Today I did the former.






I stop sanding when (a) I have sanded the whole of the neck heel and the tail block, and (b) the sides are sanded for their full length. If unsure, I run a pencil over the area in doubt and sand until the pencil marks are gone. We will see this used later as well.

Obviously I check that the sides are equal heights, and if not I sand until they are.

Now I glue in linings, which are a bit deeper than those I used for the top/sides join because they have to accommodate the curve. So I glue them on in sections - here are the first two bits going on. When all the linings are in place I level them to the sides.






I was going to use offcuts from the sides for this, as they will be visible through the sound hole. But the wood was recalcitrant, and I got impatient, thus plywood again. Plywood is better structurally, because I don't get gaps in the glue joint where the profile of lining and side didn't quite match, but doesn't look quite so classy.

Some will note that the block screwed across the sound hole is still in place. At this point the body is very flexible and I don't want to crack it during sanding, so as much holding down as possible is good. Feel free to keep reminding me to remove it before glueing the back on. But the good thing with hide glue is that if I forget it's easy to remove the back and unscrew the block!


----------



## profchris (14 Sep 2016)

On Monday I completed the linings, including making pockets for the back brace to sit in.

The linings are glued on a little proud of the sides and then taken down (initially with a plane, then by sanding) until they are EXACTLY the same height as the sides. How is "exactly" achieved?

Simples, my children. Rub pencil along the top surface of the sides and keep sanding until all the pencil is gone. Then you know your linings match the sides.







Once all the sanding is complete, it's a good time to take out that block screwed over the sound hole, as it won't be needed any more.

The back brace is made so it sits in the pockets and is gently curved, the centre being about 2mm higher than the sides.






There are two reasons for this. The first is aesthetic - you don't really see the tiny side-to-side curve, but it does just enough to make the back look even better. The second is more important - the back has to be glued firmly to the brace, but I find it easier to glue the brace to the sides now, and then when I put the back on I make sure it is also glued to the brace. The slight arch ensures that the brace pushes up into the back, so I'm confident there is contact all along the length of the brace when glueing.

Finally for today I clamped the back in position and marked the shape on the underside. then I cut it about 1/4 inch bigger all round. I don't want a big overhang when glueing the back on, because if I put any pressure on the unsupported edge it might crack, so the less unsupported edge the better.






But as we shall see, by using hide glue I can rectify any glueing gaps between back and sides once the glue has dried, so I'm not going to be too desperate about clamping pressure there.

No glueing the back on today though, as evening is here and I have a long day in the office tomorrow. I will need to wait for a low humidity day to glue the back on, so everything is on pause until then.


----------



## profchris (14 Sep 2016)

And, having survived the heat in London on Tuesday, today the back goes on! (drum roll, maestro please)

Humidity is down to around 50% in my workshop which is important. Once the back is on everything is locked in place, so if the wood shrinks something will give - usually the back or the top cracks (but I glued the top's brace and bridge patch on in lowish humidity, so it would probably be the back).

This is the last chance to rethink the neck angle, because the neck can flex at this stage - I'm making the gap at the zero fret about 10mm with just light finger pressure.






I'm still convinced by my earlier calculations, so the 1.5mm spacer goes in and the neck is held down to the board.

A light sanding round the rim and I can start glueing. This is where hide glue is particularly helpful, because it reactivates when warmed (until it has dried properly). So I paint glue around the rim and along the brace, wait a couple of minutes for it to gel, and then paint on a second coat. Once the back is closed I can't get in to clean up squeeze-out, but one coat might not quite be enough.

While the glue is still liquid I place the back in position and clamp it at heel and tail. This is important to get right, so as to line up any figure or book matching in the appropriate position. Within a minute the glue will start to hold, so the back shouldn't move.






Now I can slow down. I clamp either side where the back brace meets the sides, because I want pressure all along that brace to get full glueing, and wrap all round with rough sisal string (this string grabs on itself, but baler twine would do the job).






A traditionalist would complete the clamping by inserting wedges under the string, to add pressure where needed.






But I add a few more clamps as well.






I could probably have managed without the string, but wanted to show you that technique.

Now all the clamps are on I simply warm the back with my heat gun, testing with my hand - once it feels hottish the glue will have reactivated and I can tighten clamps/push wedges further in.

Woodworkers will say, "Not enough clamps - there will be gaps!" And they're right. But hide glue lets me sort these out later as we will see.


----------



## profchris (14 Sep 2016)

Two or three hours later the clamps can come off and I pare the overhang of top and bottom roughly back to the sides. Knife, chisel, small plane - whatever works for you. Beginners should note to remove wood "downhill' so they are not trying to cut into the grain - this means you trim towards the waist, so you can gouge that, the neck, so you can jam a chisel into it, and the tail (no hazards there). Try not to make marks you can't sand out! I leave the last half millimetre to be sanded away, as I will be sanding the sides anyway.

At this stage I can fix any obvious gaps in the back/sides seam. Heat up my glue pot, dip my brush in he hot water and dribble a little hot water into the gap. If it's a big gap, add a little more glue. Clamp, heat and allow to dry.

At sanding time small gaps might become visible, and they get the same treatment.

And this is what I now have:











I thought I'd weigh it to see if I was achieving my aim of light building. 240 g/8.5 oz. For comparison the lightest soprano uke I've come across is 220 g (with wooden pegs and no separate fretboard), so this is only about 15g heavier. That'll do me. With fretboard and tuners it should turn out around 275 g. Factory made Chinese ukes, i.e. the whole mass market, usually weigh in around 320 g.

And we're now caught up with the build, so updates will come in real time. Next up - binding the top.


----------



## custard (14 Sep 2016)

This so entertaining and informative it feels like it should be behind a paywall!

=D>


----------



## giantbeat (14 Sep 2016)

beautiful build, my former business partner was a guitar maker before we teamed up, I always thought he would build some in our workshop one day, i never got to see him make any before he got out of the wood work game, love the craft & Uke's are just so inviting to look at as an instrument.


----------



## profchris (15 Sep 2016)

Once I've trimmed back the overhang of top and bottom I can check for any places where my glueing was less than perfect. There are no gaps (hurrah!) but a couple of places where the glue line is visible, which means the join wasn't clamped enough there.

I can improve these by dribbling a little hot water onto the glue line, let it soak in for 30 seconds or so, apply a clamp and warm the joint with my heat gun. I can see the glue turn back to liquid, and at that point I tighten the clamp enough to get a little squeeze out. Then leave to cool.

Before:






After:






The line still looks a bit thick but I suspect it will disappear once I've sanded some more. If not I can repeat the process until the line won't improve.

This method only works for hide glue, and its beauty is that the joint is just as strong (if not stronger) afterwards. With Titebond you could warm the joint and clamp - Titebond softens with heat, so you should be able to close up gaps somewhat. However, that part of the joint is probably weaker afterwards. This won't be a problem for a few spots, as there is little stress on these joints. If you apply stress, e.g. by sitting on the uke, then failed glue joints is the best possible outcome!

Now we come to binding. This is quite easy in theory, but requires you to be in practice with chisels. The binding is 6mm high x 1.5mm thick, and fortunately my sides are about 1.5mm thick. So I use a marking gauge (sharpened to a chisel profile, not a point) to scribe a line 5mm down from the top. Then I deepen that line with a scalpel.

Now all I have to do is chisel away until I've removed the sides portion. My choice of plywood as a lining is helpful here, because it's a different colour from the sides. Once I've removed the wood I don't want, I clean up with a tiny shoulder plane.






You can see in the picture that I've started creating a pocket in the side of the neck to take the end of the binding. This will be hidden by the fingerboard, so doesn't need to be elegant or accurate (helpful as it's hard to get tools in, so I'm largely nibbling out wood with the scalpel).

Tips for cutting the binding channel:

1. Chisel from low point to high - here I started next to the neck and worked back to the top of the curve of the upper bout. Then I started again at the waist and worked up to the top of that curve.

2. It's easiest to remove the wood between your scribe line and the joint of the top first, and only then take the top back to match. Any slips when cutting away part of the top will be visible, so stop early and switch to the shoulder plane.

3. However, if your chisel is not narrower than this, there is a risk of jamming it in between the shoulder of the binding channel and the top, and levering the glue joint open. With hide glue this is fixable (see above) but best not to. So I swap from my 1/8 to my 1/4 chisel regularly.

4. Sharpen regularly. I've cut 1/4 of the channel, about 5 or 6 inches, and it's time to resharpen.

5. Go slow - I do this in 5 or 10 minute sessions. Of course, if you're a chisel maestro you can cut the whole thing in one curving swoop.

There are brave souls who cut their binding channels with a router. Only occasionally do they hurl an instrument across the workshop as the cutter catches.


----------



## profchris (16 Sep 2016)

Onward with the binding.

I completed the binding channel and this time really worked on the three aspects which I get wrong.

1. Making the curves flow nicely when looked at from the top. Any angles really stand out, so I smoothed them out. At this stage I don't care too much if the channel is equally deep all the way round, so long as it's at least as deep as the binding. If the sides stand proud I will scrape them back to the binding.

2. Getting the channel deep enough at the waist - for some reason I tend to cut it too narrow there.

3. (most important) Getting the base of the channel (i.e. where the binding will meet the sides) flat. It's so easy to leave this sloping outwards, and if you do there will be an obvious gap. I scrape with a chisel held at an angle, as well as planing, so that if anything the base slopes inwards rather than outwards.

Now to glue the tortoiseshell celluloid binding on. I'm using CA/superglue, so I brush a thick coat of shellac along the binding channel and over the adjacent edges of the top and sides. This is to stop the glue wicking into the wood. The alternative is some kind of acetone-based cement (Duco is the favoured brand, but hard to get here in the UK), which creates a huge gooey mess in my hands at least. Neither hide glue nor Titebond hold celluloid to wood.

I start by sanding the side which will sit in the base of the channel, because binding is often rather rough at the edges. Then I use a cabinet scraper to knock off the inside corner, so that if I've left any bumps there in the channel the binding will still sit flat.

Then I put one end into one of the pockets at the neck and taped it round to the waist along the binding/side join like so:






The clamp is to stop it springing out, which it wants to do. It's a good idea to heat the binding gently until it is JUST hot to the touch at the waist. This will set it into shape and make it easier to get tight to the body. But gently is the word - a fraction too much heat and celluloid starts to distort (you all know how I know that!).

Now I run a little CA along the join between top and binding for about an inch, press the binding close, and tape it applying tension. Repeat, repeat, repeat.






How much CA? two or three drops per inch I'd guess. For the entire binding I won't use a full 5g tube of glue.

Once I get close to the waist I add more tape around to the tail (i.e. I only tape up the binding/side join about 1/4 the way round each time, say 6 inches). This is because, as I press the binding in tight, a gap opens up further along.






If you attach the binding all around and then glue, you'll find that gaps are unclosable because the binding is in fact too long.

I stopped here because it was dinner time, and this is a point where the binding is not under strain so won't try to spring away from the sides. Will finish off tomorrow.






And immediately after I took this pic I realised I'd forgotten to add the clamping caul at the waist (wine cork cut lengthwise) - the clamp is not putting pressure at the lowest point of the waist curve and was leaving a gap.


----------



## profchris (19 Sep 2016)

Now the binding is glued on it needs cleaning up. The best tool is definitely a cabinet scraper.

On the top the binding is installed proud of the top (see at the tail, which is still to be scraped). So all I need to do is to scrape until the shellac is removed, and then I know the binding is flush to the top. No significant gaps, which is very pleasing. Even a tenth of a millimetre gap is quite noticeable here.






The sides are slightly different. In theory the binding channel was always a little deeper than the binding, but in practice it wasn't. If the sides stand proud of the binding I simply scrape away wood until I knock the shine off the binding. Then I know they are level. If the binding is proud of the sides I need to scrape carefully, trying to remove as little as possible from the top surface. I don't mind if the binding slopes inwards a fraction, because that will be largely invisible. But if I narrow it as seen from the top, that _is_ very noticeable.

I'm aiming for something like this - all shellac gone, gaps are tiny and should fill with finish.






But there are, of course, spots where the gap is quite noticeable.






I can sort these out by applying shellac to the wood if needed, and then dribbling the minimum possible CA into the gap, to melt the binding into the CA and leave a surface I can scrape flat.

Here's a similar gap, now filled and scraped.






You might notice there is a common thread running throughout - make all the parts a fraction over size, attach them, and then remove the excess to get the best possible joint. Making the parts exactly to size and then joining them doesn't work for the hand builder - it might be OK for a factory using CNC technology and jigs/moulds, but even there I suspect there would be inaccuracies which spoil the look of an instrument.

Once all is as good as I can make it I'll do some more work on the top, and then attach the fretboard.


----------



## profchris (23 Sep 2016)

Glued the fingerboard on using hide glue.

The problem with fingerboards is that they tend to curl up at the edges if you use water-based glues (this includes PVA and aliphatics like Titebond), so many builders use epoxy for this. But I was cunning - I wetted the upper surface as well as applying glue to the lower surface, and then clamped putting the pressure along the edges of the fingerboard.

It still curled!

Fortunately I can reactivate the glue with moisture and heat, apply pressure along the edge and close the gap. If, that is, I can work out how to apply pressure just to the edge.

This is my eventual solution (having made and discarded various-shaped cauls):






The block between the horizontal bar of the clamp and the fingerboard prevents the clamp from tilting backwards, and the eraser stops the head of the clamp from sliding across the back of the neck.

So the procedure was: dribble warm water into seam, wait two minutes, heat, apply a little more water, wait 30 seconds, clamp. The seam closed up and I got squeeze-out of glue, so all is good. I'll repeat this down the fingerboard on both sides, and eventually I'll have the damn thing flat.

The head plate, which is next, will have the same problem, but because the back of the neck is flat it will be easy to clamp.


----------



## profchris (25 Sep 2016)

The clamping method didn't work, so I reverted to a tried and true favourite - PVC electrical tape which is stretchy and thus applies pressure at the edges. 

The patient undergoing treatment:






And of course we need a headplate; this is primarily decorative, though it does strengthen the headstock a little, and it also provides a slot for the nut (strictly, string spacer because I'm using a zero fret) to sit in. I found a piece of pretty koa which couldn't be used for the body because it had structural weaknesses which caused it to crack along the grain lines in various places. This is no problem for a headplate because it's glued down to solid wood:






Next I shall cut the headplate back to the final headstock shape, and then start fretting the fingerboard.


----------



## profchris (30 Sep 2016)

Headplate is shaped, and fret slots cut. This is how we're looking at the moment.














I've also added markers at 5th, 7th and 10th frets. Rather than buying fiddly mother of pearl dots, which I don't much like the loo of anyway, my local charity shop has supplied me with a 4mm plastic knitting needle. 4mm holes, dab of CA glue, cut off just above the board and level once the glue is dry.

The fret slots obviously have to be at least as deep as the tang on the fretwire, but not very much deeper or you have very visible slots in the side of the fretboard. Also, cutting all the way through the fretboard weakens the structure of the neck, because the fretboard is a laminate layer which therefore adds strength. But the most important thing is deep enough - if too shallow at any point the fretwire will sit high, and this causes problems when fret levelling.

So you need a specialist luthier tool, which takes a couple of minutes to make:






Bend the fretwire (cut through the tang first), and then file off the barbs on the tang of the short leg. The short leg is then used to check the depth - if it sits down flat, the slot is deep enough. I make one of these quite regularly, as they get lost in between fretting jobs.

Note that soprano ukulele fretboards are usually flat. Steel string guitars and some of the larger ukes have a radiused fretboard. i.e. it's taller in the middle than at the sides. Same tool for checking fret depth, but the leg can be shorter because it's only checking the depth at a single point.

Next job: installing frets.


----------



## profchris (30 Sep 2016)

And by the way ....

I bought a packet of decorating scrapers/spatulas in a local bargain shop, £1 for 4. They are thin spring steel, and I thought they might come in useful. The two thickest make excellent scrapers for fine work - no need to work on getting a nice square edge or burnishing and turning a burr, just hold upright and swipe a couple of times on a diamond stone and scrape away! The edge doesn't last very long but takes only seconds to restore, and the thin bendiness gives me very fine control. Worth investing £1 if you find any and have small areas on which you want to get a fine finish. I plan to do no sanding at all on back and sides of this uke, so no dust!






And finally a question for the remaining readers (if any!) of this thread. Pretty much all the woodworking is now done - I have to install and level frets, glue on the bridge, drill holes and install tuners, and then finish the whole thing (brushed shellac is my plan).

Do you want to see all these processes in the same detail, or just a couple of updates as each stage is completed? From the comments I can tell that some of the construction techniques are interesting to other woodworkers, but I've never seen a table with frets.


----------



## SteveF (30 Sep 2016)

i want to see it all please, if you don't mind
i made a cbg ages ago....i know nothing like this at all quality \ skill wise
but i could have learnt so much from watching this build

Steve


----------



## profchris (30 Sep 2016)

SteveF":1t2fgljr said:


> i want to see it all please, if you don't mind
> i made a cbg ages ago....i know nothing like this at all quality \ skill wise
> but i could have learnt so much from watching this build
> 
> Steve



One loyal reader is enough! (though I see that 20 others have looked in since my last post, so you may not be alone). And I'm documenting this in full on a ukulele board for Jenna, my "client", so it's just cut and paste to reproduce it here.

If anyone is inspired to try their hand at building a uke or guitar, I must stress that what I do is only one of the possible ways to build. For example, the Spanish Heel I use is not right for a steel string guitar, because the tension of steel strings tends to distort the body over a number of years so that the playing action rises. At some point the neck angle needs to be changed (called a neck re-set), and that's really hard and messy with a Spanish heel. Dovetail or bolt-on is the answer there, research online will reveal how. And for a cigar box guitar, which has a nice flat side to mate the neck to, some kind of bolt (or even a long wood screw into the neck) would be easier. In other words, you need to modify your building to suit (a) what you're making and (b) the way you work best. Some people just hate hot hide glue, and there are very fine makers who use nothing but Titebond Original (never TItebond III or, horror, PU glue!).


----------



## skipdiver (30 Sep 2016)

I'm following with interest, so keep it up.


----------



## profchris (30 Sep 2016)

I was inspired to fret the uke this evening, and all was done in 30 minutes (a new record for me). The critical factor is fret slots which are the right width and depth, and I nailed it this time, so every fret went in right first time with no fuss. Additionally, I brushed a smear of hot hide glue along the tang before inserting the fret, and this did indeed lubricate the insertion. 

[This line left intentionally blank for off-colour jokes]

Equipment is as below:






Soft faced hammer (plastic or brass), flush cutting side cutters, hide glue (optional), sandbag. The sandbag provides a backing for the neck when hammering frets, though I'd probably have been OK without it because these went in easily but not loosely. But it would be sad for the headstock to break off at this point, so I use the sandbag (sand from a pet shop, for parrots etc, which is clean and comes in small quantities. Sand inside stout plastic bag, all inside an old pillow case because the plastic bag will split at some point).

I tap in the far end of the fretwire, tap along to the near end, wipe off glue squeeze out. Then cut the wire off as flush as I can, and tap again until I'm sure the fret is fully seated to the fretboard. Several light taps are better than a few heavy ones, which can dent the fretwire. If it won't go in easily , the fret slots need attention. For really tough fretboard woods like ebony, it might be sensible to chamfer the slots slightly with a triangular file.

Next: fret ends, fret levelling, re-crowning.


----------



## deema (30 Sep 2016)

I've loved the thread, really lovely work and a fantastic write up. Thank you


----------



## profchris (3 Oct 2016)

We need a bridge.

First I have to work out where the bridge has to be glued on. If I just work from the centre line it might look wrong, and even be in the wrong place if the neck doesn't line up 100% with the centre line. The bridge is made from a block of suitable, vertical grain wood (I'm using sapele, an offcut from the neck), 12mm x 12 x 57 mm, which gives enough glueing footprint to hold the string tension and looks about right once it is shaped. 

So I put masking tape on the top and extend the edges of the fingerboard to draw lines on the tape. Then I can draw a line parallel to the frets and offer up my block. Here I can slide it left or right until it looks good, whilst using those lines to work out where my strings have to go ('cause they need to run over the fingerboard with a margin at the edges, otherwise it won't play). As it happens this bridge sits pretty symmetrically, but you can cheat by running the strings slightly off the symmetrical to get a good visual effect.

Then I measure along the centre of the fretboard - I want twice the zero fret/nut to 12th fret distance _plus_ a fraction, called compensation. When I press a string down I stretch it, which makes it sound a bit higher. So I compensate for that by making the string a little longer. I know from experience that I need 2-3mm, so I place the front of the bridge 2mm beyond the scale length. I can add more compensation once the strings are on, by working back the front edge of the saddle.

Then I scribe round the base of the bridge, remove the tape, and build up the edges with more tape so I have a pocket to slide the bridge into while glueing.






[the front edge of the tape is in fact parallel to the frets, just the camera angle makes it look off]

I'm using the simplest possible style of bridge, copied from a 1920s Kumalae which I own. The block is simply drilled and cut to hold the strings. The front edge becomes the saddle, across which the strings break, and the portion behind that is shaved down.

This is how it looks after careful marking up, drilling and slotting:






The 4mm holes take knots on the end of each string, the strings run through the slots and over the (to be constructed) saddle. The strings are spaced 13mm apart - this measurement isn't set in stone, but less than 12mm feels cramped and more than 14mm can make strumming difficult.

The pencil lines show the string paths and there was a horizontal line to ensure i got my string end holes lined up. You might just see the line scribed in 3mm from the front edge, which marks out the saddle area. I will work the back portion down _after_ the bridge is glued on, because that's easiest for glueing.

The disadvantage with this style of saddle is that it can only be adjusted downwards. So if I make a mistake, all I can do is remove the bridge and glue a new one on. But I've found that, assuming I get it right, either the action (string height at 12th fret) stays stable over time or increases because the top pulls up slightly. So downward adjustment is all that should be needed, by planing or sanding down the top of the saddle.

Finally I glue the bridge on, having made sure its base is an exact fit to the top. I use hot hide glue, which is the best for bridges because it won't creep over time or if the uke gets hot - either it holds, or pops off. Clamping is clearly an issue, and you can buy or make clamps which fit in through the sound hole. But much simpler is to do a rubbed joint (rubbing the bridge beck and forth on the top until the glue starts to grab, and then holding it in position for a few seconds). Once it's in place I clamp it like this:






The block over the fretboard keeps pressure level on the top of the bridge, and the clamp is at the neck block area which is solid all the way through. _However_, the top is unsupported under the bridge, and remember it is 1.5mm thick plus just over 1mm of bridge plate. So gentle pressure only!

Once the glue is dry I can shape the bridge. But before that I need to level the frets, as I'm using the height of the strings at the 12th fret to determine the height of my saddle. Currently the bridge gives me 3.5mm at the 12th fret, and I'm looking for 2.5mm. So I'll need to lose 2mm off the bridge, which will bring it down to 10 mm, just above the middle of my target range (6-12mm).


----------



## custard (3 Oct 2016)

I look forward to new instalments of this thread more than House of Cards, and House of Cards has Kevin Spacey!


----------



## profchris (4 Oct 2016)

We can't keep Custard waiting ...

Today, frets.

You can see from this pictures that the ends of the frets are sticking out, and they are really sharp! Not good for playing.






So step one is to file them back to the edge of the neck. I use a file angled at about 30 degrees, so the fret ends slope in from the edge of the fretboard, and then finish off with a diamond stone. The test is to run your fingers along the fretboard edge - if you can feel bumps, you're not there yet. There is a risk here of dinging the body or the headstock, so I put several layers of masking tape on the danger areas.

Once the fret ends are sorted we need to make the frets level. They might _look_ level, but they're not. So tape across the board leaving the frets visible, and I tape over the zero fret because I want to keep that one at its full height.

Now use a magic marker to put some ink along the top of each fret. You can see why I taped the board, as at one point I slid off the fret (and magic marker doesn't easily come out of wood).






Once that's done, slide a diamond stone back and forth along the frets until you can see a full width line of metal across each one. I watch the first fret (nearest the headstock) - once that has a line I concentrate on the next fret along, and so forth. I'm OK if the fret plane falls away towards the body; the important thing is that no fret is higher than the fret before it.

This is the result:






You can see that on some frets the stone has just touched the top, whilst on others (the high ones) it's ground a flat.

Now, playing on flat frets is uncomfortable and produces poor intonation, so I need to restore their curve. This is known as crowning. I have a curved crowning file, but it's really designed for larger guitar frets. So I use that to start on the frets with the big flats, and then finish off using a small triangular file. I'm aiming to curve over each side of any flat, so that my curves meet in a line across the middle of the fret. It can help if you reapply the magic marker, and then file until there is the thinnest possible ink line across the top of the fret. Frets are soft, so file gently!

Here are the crowned frets:






Now I just use my files to take away any sharp corners at the fret ends, and then polish up with wire wool.






And we have a fretboard with flat and smooth frets, ready to play.

Finally today I've worked down the bridge. I simply sawed down about 4mm, removed the wood I didn't want, and then reduced the height of the saddle part until I got an action of about 2.75 mm at the 12th fret. Final height and intonation adjustment will be made once the strings are on. And a bit of sanding to clean up any chisel or plane marks.






All (all!) that is left to do is finishing, making the nut/string spacer, drilling and fixing tuners, and then final fettling so it plays well.


----------



## profchris (8 Oct 2016)

Now I'm into finishing, which means there is very little to show by way of photos. But I thought my process might be of interest, if only because (having tried most of the other possibilities) I think it's about the simplest possible for an amateur (other than simply spraying clear automotive lacquer from a rattle can, with which some can achieve rather good results, but at which I'm a complete failure!).

My finish of choice is clear shellac, bought ready-mixed (Liberon is your only brand here, though the cheaper hardware store brown ready mixes work quite well too). I'm not French polishing, but rather brushing it on. So I suppose my finish is spirit varnish.







Once everything is scraped or sanded as well as I can I wipe on two thin coats with a paper towel, leaving an hour or two between them. This avoids end grain areas like the heel absorbing more finish than the rest and thus becoming darker.

Then I start on the neck, masking off the body and fingerboard.






The reason for doing them separately is that it's impossible to brush into the neck/body join without getting finish on the other side of the join, with the result that a visible build-up of extra finish occurs either side of the join. This way the only bit which gets double treatment is the join itself, and that helps fill any gaps.

I use a flat, fine hair artist's brush, and apply the finish in a single coat, working from heel to headstock. It begins to dry immediately, so you mustn't go back and re-coat any bits you missed - catch them next time! After about 8 hours I can take any nibs off with P1000 paper on a cork block, sanding very lightly indeed, and then re-coat. No more than two coats a day.

Here is the neck after three coats, and I reckon one more will do it.






I'm happy with a fairly thick film of finish on the neck, because I don't want it to be so thin that it wears quickly away through playing. This mahogany has small pores and not too many of them, so I've left the pores unfilled. It gives a decent look, and helps stop the neck feeling too sticky when playing (a really high gloss can be a problem here).

The koa headplate had some fairly large pores, so I brushed on three coats and then, using a finely set scraper, removed the finish back nearly to bare wood. This has pretty much left the pores filled with finish (for some reason I don't understand, shellac never fills up pores, but seems to settle to an even film which therefore includes pores as it builds up. But as there is finish in the bottom of the pores, once I've cut back most of them are now flat at the base).

Here is the headplate after the process and with one layer of finish brushed on top. I reckon a second coat is needed, and then there will be final shining up which I'll show later.






I like shellac because, as you can see, it really brings out the figure in the wood.

Next the body, which is a similar process to the headplate (but not quite, because we need a really thin film of finish to avoid killing the sound of the instrument).


----------



## custard (8 Oct 2016)

You know how, when you're coming to the end of an excellent book, there's a tinge of sadness that it'll soon be over?

That's how I feel about this thread.


----------



## profchris (9 Oct 2016)

The ending will be a little drawn out, because I'm waiting for tuners to arrive from China. Against my aesthetic judgment I have to use geared tuning pegs, rather than metal friction pegs, because young Jenna would find the frictions too difficult (and a uke she can't tune is no use to her at all). There appears to be a drought of geared pegs in the UK, with only the most ugly designs available.

But the ending will not just be pictures of the finished uke, because I do play a bit. So you'll also get a snippet of video to demonstrate that it does in fact work.


----------



## AJB Temple (10 Oct 2016)

Excellent!


----------



## happymadison1978 (11 Oct 2016)

Absolutely love this thread, came to it late but it's fabulous craftsmanship and your explanations are so very clear.

Thanks so much for taking the time.

Stephen


----------



## Woodmonkey (11 Oct 2016)

Looks fantastic, keep it coming!


----------



## profchris (14 Oct 2016)

Finishing the body, and there is an important difference from the neck. In theory the finish on the neck could be as thick as I like, but on the body I want a really thin film. A uke is so small that it has trouble producing any sound at all, and a nice thick dipped finish will kill the sound completely.

So, a couple of wiped on coats of shellac, and then I begin brushing on the shellac as before, levelling back every two or three coats with a cabinet scraper with a very fine edge.

This is after two brushed on coats, not cut back, and you can see that the pores are still very visible.






After five coats I remove almost all the shellac, just stopping short of the bare wood, which shows me that most of the pores are filling nicely.






The question is where to stop. Another couple of coats and cutting back might give me a completely filled surface, but (a) I want this to look hand made, not produced with spray gear in a factory, and (b) even if I fill all the pores, the finish will shrink back over the next year or so, which means the boiled sweet effect won't last.

So this is where I stop brushing and wipe on shellac. After two wiped on coats it looks like this:






I'll probably wipe on two more and then level the surface very lightly with cutting compound (T-Cut is what I use). Or, as it's pretty shiny, I might wipe on one more and then simply wax. I don't know precisely how thick the finish is, but definitely less than 0.1 mm.

You can see that this blackwood scrubs up well (back view with finish, front view has just one wiped on coat of shellac).


----------



## bugbear (14 Oct 2016)

profchris":26yesqh3 said:


> In theory the finish on the neck could be as thick as I like, but on the body I want a really thin film. A uke is so small that it has trouble producing any sound at all, and a nice thick dipped finish will kill the sound completely.



You mean those nigh-luminous painted ones in the Sue Ryder charity shop might be other than excellent?!

Say it ain't so, Joe!

BugBear


----------



## lee celtic (14 Oct 2016)

Very interesting read.. I had no idea the body on those things was so thin..


----------



## profchris (14 Oct 2016)

The Sue Ryder ukes are remarkable. I occasionally look at budget ukes to see how much work us needed to make them vaguely playable. The Sue Ryders are the only ones where I can see no way at all. The inch-thick finish is the least of it. 

If you know a child whom you wish to deter from ever making music, this is the device to purchase. And the luminous green one, with fluorescent football decorations, is on special offer at £9.99!


----------



## profchris (21 Oct 2016)

The tuning pegs arrived from China, and I thought "Obviously, I should complete the finishing before I string up this uke, only sensible way to proceed." Oh yeah?

So here we have a preview of what the final product will look like, only it should be shinier.






I'm delighted to say that the action (string height to the underside of the strings measured at the 12th fret) is about 2.4mm, and my target was 2.5mm. It may well rise to 2.6mm as the top deflects under string tension, but I don't expect any more than that. This makes the strings comfortably low, for easy playing, but still high enough not to buzz if you strum hard.

Readers may recall that I left the saddle unshaped, because I'd want to add compensation for each individual string. What I'm looking for is for the 12th fret harmonic* note to sound the same as the note when I press the string down at the 12th fret. I've placed the bridge so that for all four strings, the fretted note is a little sharp compared to the harmonic. To make them the same, I carve away a little from the front of the saddle, and keep comparing the two notes until they are as identical as my ear can detect.

[*Footnote: Harmonic notes are what you get if you touch the string in the right place and pluck it. In this case, the 12th fret is half the scale length, so I touch at half the string length and pluck. This makes each half of the string vibrate separately (don't ask me why; physics probably, or maybe pixies) and thus gives a note an octave above the open string (OK, _almost_ exactly an octave for any physicists out there). My 12th fretted note should be an octave above the open string, so comparing this with the harmonic tells me whether I have the saddle shaped correctly.]

The result is a series of scallops in the front of the saddle. The thickest string needs most compensation, and you can (maybe) see that the scallop is deepest for that string.









Once this was done I obviously had to play it, to see how it would sound:

https://app.box.com/s/lidzck6lxpfa06iph44kf48db9eoafkm [click to play]

You will hear that I describe the G string as "buzzing like a wasp" (actually not that bad, but I'm allowed a little hyperbole at this stage). This is because the top of the saddle is still flat. As the string vibrates it touches different parts of the flat top several thousand times a second, each producing a fractionally different note, and thus the buzz.

To fix this I've removed the strings and rounded over the back of the saddle so that the strings curve gracefully across it and finally leave it at the point set by my scallop in the front. I've also cleaned up the front so that the scallops are gentle curves, rather than the gouges shown above.

I've also given the bridge a couple of coats of dark French polish, as bridges seem to look best if they're darker than the top. The fretboard has had a light coat of boiled linseed oil, so it too is darker and quite spiffy looking.

So now it's shellac/scraper/shellac on the top until I'm content, refit tuners and strings, and then I keep it and play it for at least a week in case I discover that one fret is a fraction high, or a fret end is uncomfortably sharp, or any other minor snag. Once it's as near perfect as I can manage it will go off to its new owner.

Not sure when the culminating video will be made, as I'm off to Singapore for a fortnight in mid-November. With luck the finishing will be complete before then, but Jenna won't get it until the end of November because I'll want to do a final polish (two weeks is perfect for the shellac to harden so it will take polishing) and fettling once I get back.


----------



## skipdiver (22 Oct 2016)

Excellent work and playing. Thoroughly enjoyed this thread. Thanks for sharing.


----------



## profchris (29 Oct 2016)

All done bar any final tidying which emerges as the uke settles down to being a uke.

Here is what it looks and sounds like:

https://youtu.be/v0ArGkl768Y

I'm off to Singapore for a trip, back late November, so when I get back I will do any last minute tweaking and then give it a final polish with T-Cut, as the shellac would be good and hard then. And of course, the formal handover ceremony will need to be arranged (I'm thinking the local Mayor to officiate, Rob Collins of tinguitar.com as donor of the wood on the big screen via Skype, brass band - nothing spectacular  )


----------



## SteveF (29 Oct 2016)

what a great WIP
cant believe its all over :_(

Steve


----------



## bugbear (24 Jan 2017)

profchris":2exagb3s said:


> The Sue Ryder ukes are remarkable. I occasionally look at budget ukes to see how much work us needed to make them vaguely playable. The Sue Ryders are the only ones where I can see no way at all. The inch-thick finish is the least of it.
> 
> If you know a child whom you wish to deter from ever making music, this is the device to purchase. And the luminous green one, with fluorescent football decorations, is on special offer at £9.99!



They're not only hideously over built - they're also underbuilt ?!

I saw one at a car boot where the bridge had separated nearly completely from the soundboard!

BugBear


----------



## profchris (24 Jan 2017)

bugbear":2vcnpzih said:


> profchris":2vcnpzih said:
> 
> 
> > The Sue Ryder ukes are remarkable. I occasionally look at budget ukes to see how much work us needed to make them vaguely playable. The Sue Ryders are the only ones where I can see no way at all. The inch-thick finish is the least of it.
> ...



I suspect that's because the bridge was glued to the finish, no wood to wood contact. I think it's a thoughtful touch, building in inevitable destruction before anyone's ears suffer permanent damage.

BTW, Jenna got her uke just before Christmas and is very happy with it - I've seen a photo where she is cuddling it to keep it safe from grasping hands


----------

