StewMac Concert Uke Kit Bracing Issue

klr

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My granddaughter asked me to build her a ukulele. I know nothing about them, so I bought a Stewmac kit. I've built a couple of mandolins and a half dozen guitars so I'm not new to building instruments, but I need a little advice about the top bracing.

The kit is a concert size with the plywood back/sides and solid mahogany top.

I laid out the braces on the plan and it appears the bridge plate is too short.

Brace1.jpg

I pushed it where it fit between the braces and got this:

Brace2.jpg

Then I laid the bridge where it will attach according to the dimensions given in the instructions and have this:

Brace3.jpg

My thoughts are that the front of the bridge will be supported by the x-braces and the bridge plate extending aft of the bridge will provide support to spread the twisting force of the bridge to a larger area of the top.

So, will it be okay to build it like that? I measured the bridge location several times and I'm reasonably confident that is where it will go.

Advice? I also have plenty of bracewood so I could just toss these braces in the trash and build a better pattern from scratch.

Thanks.
 
So, will it be okay to build it like that? I measured the bridge location several times and I'm reasonably confident that is where it will go. Thanks.

No. Not okay. The bridge plate needs to go completely under the bridge at the required scale length position. This plate was cut wrong or was meant for a soprano. Call Stew Mac or email them with the above picture. I'm sure they will replace it with the properly sized bridge plate. Their customer service is excellent. Even though it is easy to make your own spruce patch, just let them replace it for you. Do not glue it out of position.
 
Do you have any wood that you could make a new one? I built the same kit and it was the same way, they need to look into this and make a correction on that piece.
 
I think I see what is going on. I was measuring based on the fretboard meeting the body at the 14th fret.

I placed the nut on the neck per the instructions, then the fretboard, and then measured. This moved the bridge back enough so that I can bring the x-brace/bridge plate forward about 1/16" and have the bridge plate right under the bridge and fit tightly to the x-braces.

So, do ukuleles not always have the neck meet the body at a fret like a guitar? The pics of the StewMac kit do not.

If that is the case, the plans need revised to show the proper placement of the baces and bridge plate.

Or I still haven't figured out what I'm doing wrong.
 
I was gifted a Stewmac tenor kit to assemble for a family member. It had the same 'X' bracing pattern as your concert size. It also had the same anomaly with the bridge plate, so I cut a slightly longer replacement. After the bracing was glued and sculptured, I performed my usual flex testing and found that it was way too stiff for my liking, so continued paring down the braces with only a slightly noticeable improvement . Reading that the older Stewmacs had good results with fan bracing, it was out with the chisels, scraper and paper and back to my standard two fan braces with a central finger brace and an elliptical bridge plate. This is a bit on the light side for some builders, but typically gives a nice full bodied sound with minimal bellying.
I'll see if I can find and post 'before' and 'after' pics of the actual soundboard.
 
I was gifted a Stewmac tenor kit to assemble for a family member. It had the same 'X' bracing pattern as your concert size. It also had the same anomaly with the bridge plate, so I cut a slightly longer replacement. After the bracing was glued and sculptured, I performed my usual flex testing and found that it was way too stiff for my liking, so continued paring down the braces with only a slightly noticeable improvement . Reading that the older Stewmacs had good results with fan bracing, it was out with the chisels, scraper and paper and back to my standard two fan braces with a central finger brace and an elliptical bridge plate. This is a bit on the light side for some builders, but typically gives a nice full bodied sound with minimal bellying.
I'll see if I can find and post 'before' and 'after' pics of the actual soundboard.

That sounds like a good plan. I'd like to see your bracing. Thanks.
 
Below is a picture of Stew Mac plan for their concert kit:

concert plan.jpg

Below is a picture of the completed concert ukulele

StewMac_Ukulele_Kits.jpg

Below is a picture of the bracing in the concert

concert 2.jpg

Note that the picture #2 clearly shows the neck as meeting at the body at the 14th fret. The scale length is reported to be 14 29/32 inches. The distance from the nut to the 12th fret would be half that distance and the distance from the 12th fret to the saddle would be half that distance again. Question: On the plan, does that half measurement come out the same to the center of the bridge plate? It should. If it doesn't there is something wrong with the plan. This predisposes that the fret intervals have been correctly cut to correspond to a 14 29/32 scale length which is kind of odd, but no matter.

My feeling is that using X-bracing on a concert ukulele is not the best solution. Again, the designer is probably coming from a guitar builders point of view which they adapted to an ukulele. Way overkill as a structural solution in my opinion. I have no idea what these things sound like, but I suspect they sound a little dead.
 
I'd like to see your bracing.

I will post it asap. Unfortunately it resides in an album of many thousands of images with, (as cruelly described by others) a chaotic, bizarre and even 'non-existent' filing system. I may take a little time.
 
I will post it asap. Unfortunately it resides in an album of many thousands of images with, (as cruelly described by others) a chaotic, bizarre and even 'non-existent' filing system. I may take a little time.

Lol. I know the feeling. I used to keep them safe on photobucket, but we know how that turned out.

Anyway, I re-measured, re-checked, and re-dry fitted the parts together.

Stewmac lists the scale length as 14-13/16" (376mm). The instructions state to place the center of the saddle at 14-29/32 from the nut.

I measured from the front of the fb to the 12th fret and came up with 7.390". Double that is 14.78" which is 14-25/32 and short of Stewmac's specs.

I used the metric side of my fret ruler and came up with 187.5mm. Double that is 375mm. Again, short of Stewmac's specs.

So how much compensation is required on a uke? Placing the saddle at stewmac's specs will give about 1/8".

Now here is how my nut, neck, fb go together.

FB location:
20191208_151633-1.jpg

Add nut:
20191208_151627-1.jpg

Neck will join body midway between the 13th and 14th fret:
20191208_151643-1.jpg

I think I'm going to email Stewmac a few pics.
 
Something goofy is going on here... The 14th fret should align with the top of the body and still give you ledge enough to allow the nut to lay flat on the peghead.

Yes, the stated scale length is 14 13/16. The instructions say to place the saddle (which should be centered over the bridge plate) at 14 29/32 which would mean they are building in 3/32 compensation. This is the standard "rule of thumb" compensation for a tenor scale length (17 inch). I would think that the "rule of thumb" compensation on a concert would be less and more like about 1/16 inch. Regardless, 3/32 is close. But 1/8th would be way too much in my opinion.

I'm wondering whether you got the wrong fretboard in this kit. Anyway, take this up with Stew Mac. I've found that their technical help is, for the most part, excellent.
 
I was gifted a Stewmac tenor kit to assemble for a family member. It had the same 'X' bracing pattern as your concert size. It also had the same anomaly with the bridge plate, so I cut a slightly longer replacement. After the bracing was glued and sculptured, I performed my usual flex testing and found that it was way too stiff for my liking, so continued paring down the braces with only a slightly noticeable improvement . Reading that the older Stewmacs had good results with fan bracing, it was out with the chisels, scraper and paper and back to my standard two fan braces with a central finger brace and an elliptical bridge plate. This is a bit on the light side for some builders, but typically gives a nice full bodied sound with minimal bellying.
I'll see if I can find and post 'before' and 'after' pics of the actual soundboard.

You said I performed my usual flex testing, what did you mean by flex testing, and how do you do it?
 
Unsure where to go with this, but ;
It is not as mystical as it is sometimes made out to be.
It is a simple procedure conducted on the braced sound board where the thumbs are firmly placed in the centre of the bridge patch and the four slightly spread fingers of each hand pull down on the periphery of the outer edges of the sound board. This is done (with a consistent moderate pressure) progressively in all directions, with the relative stiffness being felt by the amount of 'give' for each direction, this is mentally noted.
Hopefully your chosen top bracing will be relatively stiff in the longitudinal direction (parallel to the strings), relatively flexible (but not at all limp) laterally from bout to bout, and somewhere in between across the diagonals. This is for the lower bouts only, don't expect useful feed back from above the sound hole.
I know that the term 'relatively' is not very helpful here, but it doesn't take too many builds to form a 'feel' for the differences in sound boards of different sizes, wood types and bracing patterns.
In the past, I have applied the same principles to unbraced boards, but it is the effect of the bracing that I want to check, rather than just the top wood. Others strongly disagree on this point.
You may have seen demonstrations where the sound board has been gripped by the edges and twisted diagonally in both directions to guage stiffness. I am unsure of how helpful that can be.
There are some very interesting presentations online showing more scientific approaches to sound board/bracing testing with very exacting jigs, loudspeakers, sound spectrometers, weights, etc and all manner of sensitive measuring equipment.
Hopefully others will chip in with their methods and experience, and provide a bit more colour to a grey area.
 
Found it.
There's a lot of wide open space on that sound board.
I'm not encouraging you to do this, but there will be less vacant space on your concert sound board.
If I can be strictly objective, for a tenor I would likely now go for the extra full fan, and a wider three fan spread.
If you look carefully you can make out the shadow of the original 'X' bracing.P1010308.jpg
 
Thank you! I'm going to build mine with that bracing pattern.
 
My first uke was a tenor that I built from a StewMac kit. While it looks good and plays fine, it doesn't seem to have the "sweetness" I hear in other tenor ukes I see online. Because I didn't know any better at the time, I just used the x-braces supplied in the SM kit, and I think the instrument is overbuilt. I've spent a lot of time studying uke and guitar construction since I built that kit, and if had it to do over, I'd have a much lighter 3-fan brace setup like the tenor uke I'm currently building. I fully expect my current project will sound much better than that first SM uke.
 
what did you mean by flex testing, and how do you do it?
An afterthought on this.
If you are following a proven plan, using the recommended materials, and stick to the given criteria, then there is little need to worry about this. Its primary value is for assessing combinations of different top woods and bracing patterns.
 
On completion, please consider posting your opinion, it could be of interest to future kit builders.

I sure will. Although my opinion may not be worth much given my lack of experience.

On another note, the holes in the heel are drilled off center. Sigh.

20191209_184030-1.jpg

I contacted Stewmac tonight and asked for an email address so I can send them pics of the neck and bracing.
 
Don't worry about that.
The position of the holes is inconsequential.
I made some 'dowel locating pins?' from SS rod. They are simply a short length of rod (a little longer than the hole) with a concentric point machined into one end. It was quite easy to do this accurately on my drill press. Brass rod would be very easy to fashion. You will need two. I was quite aggrieved when a few years later, I saw a set of common diameters offered for sale in a nice little case with matching drill sizes. They may be available in your area or online. They are indispensable for accurately positioning any dowelled joint components.
The idea is to offer up the pinned component to the other and after careful alignment, press firmly to leave two pin point impressions on the receiving piece. Providing that you can precisely drill from that point, you will have a perfectly aligned neck. I found that the positioning was simple and quick when done (inverted) on the flat machined surface of my table saw after carefully marking the lateral alignment on the instrument body. This eliminates any possibility of rotation.
The ruler and pencil method leaves too much room for error.
 
Thanks for the help. I'll look for a set.

The inverted alignment method is great. I have a granite surface plate that will work for aligning the neck.
 
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