Spanish heel problems

Hello, this is my first post, and I am pretty desperate about a problem I am currently having with a batch of 4 tenor ukes I am building. I am hoping someone here has a smart idea of how to solve it.

Being unsatisfied with the way the sides are wedged into the heel slots with thin slivers of wood, I decided to try something else this time. I adopted a different kind of wedge joint, where the sides of the heel slots are not parallel to each other, but flare slightly to allow a wider wedge driven into the slot from the back to close the joint. This is something Jose Romanillos has been using for classical guitars.

BUT - I managed to cut these slots the wrong way around, meaning they are narrower on the side of the back, rather than on the top side as intended. This means that after the top has been glued to the neck table, I can no longer access the wider part of the slots to drive the wedge!!!

My last resort is to "fill" the slots with a corresponding wedge, thereby making the sides parallel again - but this would be to admit defeat entirely, and to resort to the original solution that left me unhappy the last time.

Pictures of the current state of affairs are attached for clarity.

Anybody got any good ideas how to deal with that problem??

Cheers - happy building - Andreas - Nene Ukes - Vienna, Austria

Go ahead and fill them, then recut. Will not affect the build and once buttoned up, there's no evidence of a "mistake". We all make mistakes (I prefer to call them "challenges") and learn from them. The next batch will be better. BTW - Nice bench!!

I don't use the wedge system at all on my necks. I could never get them to fit to my satisfaction. You might like to consider how I do this.

I use a very snug slip fit. That is to say that the slot to fit the side is cut with a blade that has a 1.75mm kerf. And the sides are machined to 1.70mm. After bending the grain has stood up a little bit and that slip fit usually needs to be adjusted by giving the sides a light sanding until they "just slip in again. When glue is applied you have to move quick because the wood will swell up again and can make those sides tricky to slip back in.

But the results are a very good neck to body join.

Hi,

You could machine your wedges to fit perpendicular to the face. One that you drop into the cavity large end first, and the second driven in thin end first. Stair risers are driven tight to the skirt board in this manner. You'd be performing the same operation in miniature. I use a spanish heel myself, and had never considered this before your post. I've been using a thinner kerf than you're using, and installing 4 tiny wedges per side.
Good luck

Sorry Andreas, I took a closer look at this, and can see your problem. My suggested approach won't work here unless you adjust the kerfs to become parallel-sided. You'll be using 2 wedges instead of the single one intended.

Slip Fit might work

Allen, I like the idea of a tight glued slip fit. What I do not like about the conventional wedging system (and why I chose the advanced vertical wedge) is that the wedge will drive the sides out of shape at the heel joint.

A tight slip does not do that, and I can easily fill the current slot with a corresponding wedge that leaves just enough width for the sides to fit tightly. I actually came up with that as my best way out myself, but had not considered gluing the joint.

Hal - the bench is my pride and joy. I built it myself from a beech countertop (2 x 9 feet) with a sturdy base, a front quick release vise, and plenty of dog holes to clamp things down. It is doubled up in places to accommodate holdfasts as well. The top is flush with the base, allowing me the easily clamp long boards for side planing etc. (for when I am not building ukes...).

Best - Andreas

Allen said:

I don't use the wedge system at all on my necks. I could never get them to fit to my satisfaction. You might like to consider how I do this.

I use a very snug slip fit. That is to say that the slot to fit the side is cut with a blade that has a 1.75mm kerf. And the sides are machined to 1.70mm. After bending the grain has stood up a little bit and that slip fit usually needs to be adjusted by giving the sides a light sanding until they "just slip in again. When glue is applied you have to move quick because the wood will swell up again and can make those sides tricky to slip back in.

But the results are a very good neck to body join.

Click to expand...

There is still plenty of wood left inside the heel ...recut the taper slot the correct way and use thicker wedges.

Timbuck said:

There is still plenty of wood left inside the heel ...recut the taper slot the correct way and use thicker wedges.

Click to expand...

Timbuck - i would do that if the tops were not already glued to the necks, giving me no access to the slots. Taking off the tops would surely ruin them, hence this is something I would like to avoid. But maybe I am missing something?

Cheers - Andreas

The solution to this is to go to the double wedge system, which is what Romanillos is using at the moment, although you may have to open up the slot a little more.. Romanillos got the idea of the wedge from a 17 th century Guitar. That's how old the method is.

If you shape the side side of the wedges it won't change the shape of the sides. Does that make any sense? Wedge from the sides is what I would do, a thick one near the soundboard (shaped to fit the sides) and a thinner one, also shaped.
Take care,
Thomas