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People have been building these lovely boxes for a very long time, so I doubt I could ever dream up anything that hasn't been done before, but I recently devised and built a jig that I'm kind of excited about.

The problem I was trying to overcome was that of keeping the blocks properly aligned while closing the box. Using standard external molds and internal spreaders has worked well enough for me in the past, but I kept wondering if I might be able to control the geometry of the neck block more accurately from outside the box, as opposed to inside. That's hard to do when you have an external mold and its fasteners in the way.

This is kind of hard to describe and a picture is worth a thousand words, so here's a shot of what I've built:



Basically, I place the rims and plate in the appropriate solara (or radiused dish) and fit them between two right angle cauls. (One thing you don't see in this photo is that the top plate should be secured in place by a caul tightened through the soundhole.) The adjustable cauls are then forced together and locked in place once the blocks are determined to be level and square. This does require me to move things during the process, which flies in the face of the idea that everything stays in the mold until the box is completely closed. However, this allows me to double-check things after the first plate is on and before the second plate has been affixed, which I found difficult to do using an external mold and spreaders.

This also requires me to drill small holes through both blocks. Not a big deal to me as I'm going to do that anyway, but this may not work for everyone.

As I said above, everything has been done before and it may be that the reason I've never seen anything exactly like this is because it's a really dumb idea. I'd love to know what you all think about this, if only to save myself a lot of heartache later!

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George :-)

How do you control the final shape of the sides?

In this case I used my external mold to affix the top plate. At that point the sides measured true outside the mold, so I switched to this jig. I then adjusted the blocks, double-checked the sides and affixed the back plate. However, you could also align the sides correctly and clamp them in place before gluing the top plate's linings--as you might for a classical guitar.

I agree that side shape is a potential problem that needs addressing. If I take this further I'll add some adjustable "wings" that can be fitted with cauls and maneuvered to keep the sides properly aligned.

Maybe this is overly complex and the external mold offers a simpler solution, which is why it is so widely used. I've had neck blocks move on me, though, which is what prompted this experiment.

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George :-)

We're thinking of doing something similar, but simply modding our outside molds to accommodate it.

Otoh, it's not an actual necessity to have the blocks square...

Nice idea. I have been thinking about going to the screwed into the mould approach on my next one.

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Pat

Hi George

I think you have a good idea. I have been using something like that for awhile. All my guitars have pick ups or end pins and all are bolt on necks so I already have the holes for bolts. The picture below shows my method - which seems to work for me to keep sides, top & back in correct alignment while gluing. - Mike

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guitarsbygiltzow.com

Michael - Yeah, I've always been intrigued by setups like yours. I'm probably just dreaming, but my ultimate goal is to try and devise a kind of Swiss Army knife cradle type thingy that carries the guitar through from affixing the ribs to the final fret set up. I can kind of see it in my head. Might be too weird. We'll see!

Ed - I don't follow you. I find keeping the neck block at a right angle to be pretty helpful. Perhaps square is the wrong word?

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George :-)

I like it a lot George. Keeping the neck block straight with a M&T joint is very, very helpful. Especially when you cut the mortise in the block before assembly like I do.

I just might tackle a similar arrangement the will work for me.

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Joe Beaver
Maker of Sawdust

Just that there's certainly room to make corrections if the blocks aren't square.

Ed,

Yes sir! I have done that to various degrees on many builds.

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Joe Beaver
Maker of Sawdust

Gotcha, Ed. Yeah, there's room for correction. I'm just exploring methods that might help me minimize the need for such adjustments. Building only one or two guitars a year, as I do, sometimes makes it seem as though I'm relearning the entire process every time I start out. Even the exercise of thinking these things thorough gives me a better idea of what it is I'm trying to accomplish at every step.

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George :-)

George,
This is very interesting and it has obviously stirred up some thought. This is exactly why we all keep coming to our forum. I'll be watching this thread. I expect there will be a lot of positive insight shared in the coming days.

Patrick

It's definitely better to get them square, or as close as you can. Just that perfection isn't mandatory, like say, the overall neck angle...

I really like the idea of making the neck block immobile, indeed a pre-slotted neck block mis-aligned in any direction can be a real headache/problem down the construction path. Getting this right can be particularly challenging for a cutaway. I don't recall ever seeing much about the assembly process for making a cutaway guitar -- so lets get started here. To my way of thinking the most important and perhaps the most challenging aspect of the build is keeping all the components on center and on plane -- especially the neck block. Here's some photo's of my special fixtures -- note the neck block locators, the hinged mold to allow easy clamping and the alignment tool to use prior to gluing on the sound-board. I am sure this will raise a few questions and get those creative juices going. And -- yes you need a work-board, to me the handiest guitar fixture in the shop!

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Ken Cierp

http://www.kennethmichaelguitars.com/

I think we started yesterday, but welcome to the thread.

I've been seeing a lot of hinged molds lately and others with the fasteners moved away from the neck and heel block areas. Those are great ideas, in my opinion. I like the neck block locators, Ken; that's a good trick.

On a cutaway, as you depict here, with its neck block affixed in two directions, I can see everything staying put quite readily. However, if you remove your "alignment tool" before affixing the soundboard on a non-cutaway, what's keeping your neck block from potentially shifting?

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George :-)

"Get started" is in reference to cutaway's in the context of your post.

The picture in the adjustable mold shows the use if the "T" alignment tool, shims are positioned to lock the rim square and on center. At that point the sound board is attached.

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Ken Cierp

http://www.kennethmichaelguitars.com/

I should also mention that the reverse round ribbon lining even when applied to just one rim edge tends to keep the profile in position. This stiffening affect is one of the reasons I like RR.

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Ken Cierp

http://www.kennethmichaelguitars.com/

And I thought I was the only one with that affliction !!!

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Joe Beaver
Maker of Sawdust

Nope. I have a collection of jigs. Aha! I should make a thing to do this! (Makes thing to do this) Does it. Puts in drawer beside previously built jig to do this...

Lol. I know the feeling. "Why didn't I think of that before?" "Oh wait a minute, I already did!"

I made some end/neck block clamping caul extension things which I think help me get everything lined up better.

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Pat

Pat,
That's brilliant! Especially the beer can holders!

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George :-)