Dimensions of bits and pieces for a tenor ukulele

[mooshalah]

Hello all!

I'm a brand-new member, and this is my first post. I hope it works!

I'm an amateur luthier in Emerald, Melbourne, making classical, flamenco and steel-string guitars and have decided to turn my hand to making a few tenor ukuleles as a diversion. I've decided on the overall shape and dimensions, I've made a few templates and moulds, and been cutting and jointing bits of Birdseye Maple, Blackwood, Sitka- and Engelmann Spuce, and even some Ancient Kauri in preparation for making two or three instruments.

I've done the usual stuff; hunted around on the internet for free plans (could only find for a soprano instrument); downloaded the StewMac manual for assembling their tenor ukulele kit; copied bits and pieces of photo's, opinions and websites, and taken overall dimensions for instruments from a variety of places.

But nowhere have I been able to find a mention of - in particular - sizes of either back and soundboard braces (of course, this will depend on the bracing pattern), thickness of fingerboard (if it's to be a piece of wood separate from the neck; I'm guessing around 3mm), opinions of thicknesses for sides, back and soundboard (depends on materials, but I'm guessing 1.5 - 2 mm for hardwoods, and 2 - 2.4 mm spruce soundboards) and comfortable thickness (not width) of the neck at the nut andthe 12th (or 14th) frets.

Also - and maybe it's not absolutely critical on a thing like a ukulele - what sort of string action height (in milimeters) should one be aiming for at the 12th (or 14th) fret? (And as an aside, any views on things like bothering to put a slight radius on the fingerboard, or 12 versus 14 frets to the body?)

So, does anyone have any opinions on this, or where I might go (without having to buy a book or set of drawings) to get such information or opinions?

I trust that this is an appropriate first post for this forum.

Thanks.

[John Maddison]

... what sort of string action height (in milimeters) should one be aiming for at the 12th (or 14th) fret? ... does anyone have any opinions on this, or where I might go

Hi (name?)

There are some pretty good resources on the Ukulele Underground Forum, notably one on String Heights. Keep looking around that Ukulele Builders Luthier's Lounge, you'll be rewarded with good info.

Generally Tenors join at the 14th, and I don't normally put a radius on the fretboard - too much friggin' around.

Cheers!

[mooshalah]

Hi John.

Sorry folks; the name's Frank.

Thanks for the links. I've only been looking for ukulele info on the net for a little while,and hadn't come across (what I suppose are the innevitable) ukulele forums. You've hugely expanded my database, and the potential for me to find out what I need to know.

Regards,

Frank

[John Maddison]

Hi Frank

... and Welcome by the way! You'll find the Ukulele Underground a fantastic global resource, many talented people including uke players belong to UU.

Cheers
John

[Allen]

Welcome to the forum Frank.

I use a Spanish heel for my necks and it's a tight slip fit with the sides into the kerf from a thin blade on my table saw. The blade leaves a 2 mm kerf but I have to take my sides down to 1.8 before bending, as the steam seems to swell them up just a bit.

Backs are generally 2 mm thick, and soundboards down as low as 1.5 for something really hard and stiff up to 2.3 for some Western Red Cedar I'm working on now.

Transverse braces I make 6 mm wide on a tenor and 8 mm tall.

Bridge patch at 2 mm thick. Lot's of ways of shaping them, some almost like a low flat ladder brace, and others more like a conventional bridge patch. I've seen an awful lot of ukes that show a crack in the soundboard right on the edge of the bridge running along the grain. None of them had a bridge patch.

Finger braces I like at 3.5 mm wide and 8 mm tall. Voiced from there. They usually end up at around 7 mm right above the saddle and taper off to nothing at each end.

Fret boards if they are flat are 3.5 mm thick, If they are radiused I start at 4.2 mm with a 12 " radius on them. By the time I've finished shaping them, the sides are down at around the 3.5 mm and the total thickness might be around 4.0 mm.

Neck without fret board is 13 mm thick at the nut and 15 mm at the 9th or 11th fret (depending on body join).

Nut is anywhere from 34 mm to 36 mm.

String spacing from 42 to 44 mm at saddle.

Action at the 12th fret is .085" for low, .090 for medium and .095" - .100" for high. Some of the low tension strings like Wurth Browns using a low G need a much higher action or they will buzz like mad. I set the action on mine now to .090"

[Insomnomaniac]

Allen, you are a saint...

[mooshalah]

Hi Allan.

Thank you very much indeed for addressing my specific questions. This has the effect of rapidly, positively and dramatically moving things along for me.

You are going a long way to reassure me that my initial thoughts were generally correct. In a way, fundamental good lutherie practices seem to be maintained, but adapted for the differences in scale of the ukulele compared to the guitar.

I wish I'd been a bit more confident of my embryonic opinion before I tried yeterday to bend a set of Birds-eye Maple sides. I left them at 2.1 mm, thinking I'd thin them to 2.0 mm after assembly. Whew! It would have been just that much easier to have taken them down to around 1.8 mm - the figure you're suggesting. I'll take the Blackwood strait down to around 1.8 mm before I start bending. The radii on this uke' are a bit tighter than a guitar.

I appreciate the clear statement regarding brace and bridge patch sizes. I had wondered whether, if one is using a hardwood for the soundboard, whether such a patch is necessary, but one or two of the instruments I'm about to make have spruce soundboards (I'm considering blackwood for the other two) and a scale length a smidgin over 17 inches (432 mm), so I'll take your advice and use patches on all.

I appreciate your comment on radiusing the fretboard. I had though to perhaps radius them a bit less severely (like 14 - 16 inches), but I guess that because the fretboards are so narrow compared to standard guitars, one will hardly notice even a 12 inch radius. Certainly, I'm not going to have any problems with thinning of MOP inlays at the edges of the fingerboard, up near the body and soundhole!

The action you recommend is pretty much in line with a flamenco guitar setup. I guess that nobody likes a "floppy" feeling up near the body, and that one sets up the instrument as low as one can go before buzzing becomes a problem. I guess I'll do mine by trial and error, starting with the highest of your figures, ands paring the saddle down until I'm happy (which often means taking things down 'til the buzzing starts, then throwing that saddle away and making a new one, with hard-won new knowledge!)

I'm now all dressed up and ready to go!

Frank.

[Allen]

Part of the reason for a bridge patch is also to help hold a radius in the top. I use them on all ukes. That is if you are building a radius into the top.

[mooshalah]

Hi Allen.

Thanks for this.

Yes, I'll put a radius onto the soundboard, using the same dish that I use for guitars. I haven't ever radiused the patch; interesting idea for say a Maple patch on a steel-string, but of no real benefit - I don't think - on a Spruce patch for a classical or flamenco - but of course always radius the bridge.

Regards,

Frank.

[Kim Strode]

Hi Allen,

I was interested by your comment about attaching a bridge patch to aid in holding the top radius. Do you simply glue the bridge patch with go bars while the top is laying in a radius dish, or do you radius the actual bridge patch in some way.

[liam_fnq]

Mostly right Kim. You push a flat bridge patch (say 1.8mm) down onto the inside of the top as it lays in a dished solara. Once dry it matches the dished shape as if the solara was a mold. You can maintain a convex top even on a soprano uke which has only a bridge patch and no fan braces using this method.

[Allen]

I use to press in a flat patch, but now I put a bit of a radius on the patch as well. David Hurd used (retired now) CF matt and pressed it into the radius dish with a shaped caul. I'm liking this idea and will change to it I think.