Brace yourself for more bracing questions about bracing

mike_tatt

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I’m getting close to assembling my first ukulele

I’ve made and formed some lovely spruce bracing already glued to the top and back and ready to trim. I’ve also made - from said spruce a backplate for the bridge.

Question 1.

I haven’t made any pieces for the spines - are they really essential.
The front and back are both two piece.

I have a 1930’s Spanish soprano - which has small spruce square’s spaced down the spine rather than a full length strip - is this enough - it seems to have been okay for 90 years on this instrument.

Reason I didn’t make a spine strip - I have no more spruce - well - not a lot - only enough to make small squares.


Question 2

I have no spruce - but I have some mahogany offcuts - is mahogany a good / suitable alternative?

Question 3

okay - this is not strictly bracing -

Is mahogany okay for the bridge backplate - I fancy using this for my next build as I want to have the strings pass through the bridge - knotted under the soundboard (or even pegged) and thought that mahogany might be more resilient to spruce.


Any feedback appreciated

Cheers
Mike
 
I am not a pro just a hobby maker, but here's my take:

The back strip is there for reinforcement and the grain direction of the strip is across the joint and not along it. It is possible to leave it out or use small cleats but its generally considered worth doing. Any wood is possible though often its spruce or cedar. See this:

https://www.youtube.com/watch?v=6podvjBY9i8

As for the soundboard, on a soprano it often only has a bridge patch as bracing and no joint reinforcement.

The grain of the patch (which should be quarter sawn) runs across the soundboard : it is often of spruce or mahogany but other light woods can be used. If a pinned or tie through bridge is used then a hardwood patch is considered better.

On a concert there may be 2 fans in addition to the patch: the centre seam may be left unreinforced or cleats or a cross banded strip added-its down to the makers preference! A tenor often has 3 fans so one of them runs along the centre seam, and in this case grain direction of this fan brace is obviously along and not across the seam.

There's lots of information on Youtube on ukes and classical guitars. The more you watch, the more you'll realise there are many opinions and many ways of doing things.
 
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Sopranos don't seem to need a bridge plate (aka bridge plate).
Mahogany would be fine for a bridge plate. Id make it .050"-.070" in thickness and longer and wider than the bridge (by say 1/8" all around at least)

The success of the top not bellying with no bridge plate (or even with one) also depends on the quality (stiffness) of your top.
Most Sopranos have a top in the range of 0.060"
 
Thank's for the info Beau

My tops are Spruce - running at about 0.66 - so seems like I'm close to the general parameters for a soprano - phew.

I'm intending on installing a bridge plate from Spruce (already made) - on uke No1 - - partly because it seemed 'the thing to do' and also I want to understand the mechanics of actually doing it - making / measuring gluing, clamping etc - so that I learn the skills.

Uke No 2 - I'm considering using bridge pins - I like the look - and was thinking that mahogany would increase the strength and reduce any wear caused by any increase in lateral tension around the bridge. Not certain if it's needed and might be overkill - but again it's part of the learning curve.

Thanks again

Cheers
Mike
 
I think you must mean 0.066. Oh those pesky zeros... I don't build sopranos so can't comment on approximate top thickness, but it all depends on how stiff your top is. As to making a bridge plate; nothing to it as long as you get the grain perpendicular to the top's grain. For a basic soprano bracing scheme go here:

https://www.stewmac.com/freeinfo/i-5351/5351.sopranoplan.pdf
 
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