Build Thread: Todd Rose Allegheny with adjustable neck

[Todd Rose]

This thread documents the construction of a special Allegheny (my SJ-ish guitar) for a customer who is a good friend of mine, named Dan. Dan wanted me to build whatever I wanted to build and extended endless patience to allow me all the time I needed to arrive at the completed guitar. Since my last post in this thread near the end of 2014, this project was put on the back burner for a period of time while I fulfilled several other orders, did a lot of repair work, etc. I've now completed the guitar and delivered it to Dan. I'm happy to report that he is totally thrilled with it. I am, too -- I can't deny that it sounds fantastic! Honestly, we are both blown away by its amazing sound. Photos and recordings of the completed instrument are at the end of the thread.

With Dan's encouragement, I made this guitar with an adjustable neck inspired by Rick Turner's design -- thanks are due also to Laurent Brondel, who makes an adjustable neck joint similar to this and gave me much useful input. Along with the adjustable neck joint, there are several new design ideas being incorporated into this guitar, which you will see in this thread.

Starting with the drawing:



Update: Apparently, most of the photo links in this thread don't work any more, and I don't have time to fix them all. Sorry! All the pics can be seen here:

https://www.facebook.com/todd.rose.7...4412412&type=3

(Please don't be offended if you send me a facebook friend request and I don't accept it. I'm not in the habit of having a lot of facebook friends I don't actually know.)

Here are a few pics of the completed guitar, to whet your appetite:

[Todd Rose]

Indian rosewood back, Lutz spruce top, figured bubinga rosette. I really like the brick reds in this set of rosewood, and the top is a sister to a top on another guitar I made, which came out sounding great.

[Todd Rose]

This is a shot of the guitar with the sister top.

[Todd Rose]

It took several drawings to get the fretboard extension shape right.

[Todd Rose]

Now here's the actual FB lying on the top. Ebony with Madagascar rosewood bindings (just happened to be the best color match I had for the reddish IRW B&S). This shot gives you a little closer look at the bubinga rosette, too, which reflects the reds in the other woods.

[Todd Rose]

Spruce and Ipe back bracing. I've done back bracing very similar to this (with results I've been very pleased with) using carbon fiber on top of spruce. I decided to do this one using all wood on the back braces. I chose Ipe for its extreme stiffness. These braces are arched by laminating them in the radius dish. They maintain the 15' radius dome of the back extremely well. They are beveled at the ends and stop short of the linings. You'll see that better when I have the "boat" done.

[lpa53]

Just beautiful! I'll be watching this build for sure.

[Todd Rose]

Originally Posted by lpa53

Just beautiful! I'll be watching this build for sure.

Thanks, Ipa53!

[Todd Rose]

Top bracing.

[Todd Rose]

These angled shots give you a better picture of the brace profiles.

[Todd Rose]

The bridge plate is laminated from spruce, palo escrito, and hard maple, and then coated with CA glue to toughen the surface against which the ball ends of the strings will bear. Palo escrito, for those who may not know, is a Mexican rosewood that is much lighter weight than other rosewoods. I used it to cap the X's, too, as you can see in these photos.

[lpa53]

Originally Posted by Todd Rose

The bridge plate is laminated from spruce, palo escrito, and hard maple, and then coated with CA glue to toughen the surface against which the ball ends of the strings will bear. Palo escrito, for those who may not know, is a Mexican rosewood that is much lighter weight than other rosewoods. I used it to cap the X's, too, as you can see in these photos.

Non-builder question: In displays of commercial makers' tops I've seen x-braces capped but usually done with some sort of cloth-like material and usually in both directions. Why do you choose wood and run it only one way?

[Todd Rose]

The braces form a lap joint at the X, like this:



The brace that goes over top acts as a solid beam because it is "capped", or bridged, below by the soundboard. The brace on the bottom needs the cap on top in order to have the strength/stiffness of a solid beam, otherwise it would be dramatically weakened by the notch.

I don't believe a cloth patch really accomplishes this, so I've never really understood the reasoning behind the use of a cloth patch.

[Todd Rose]

While I'm here, a little more explanation of the bridge plate. The spruce, palo escrito, and maple laminations alternate grain direction. The p escrito center lam grain is parallel to the soundboard grain, while the spruce and maple go cross-grain. This gives the bridge patch more stiffness in the direction that helps resist distortion from the string-tension-torqued bridge. At the same time, the plate is virtually guaranteed to never split as all too often happens with conventional bridge plates. This bridge plate is thin, very lightweight, and appropriately stiff, which makes it work great both structurally and acoustically. With the CA-coated hard maple top lam, it is a plenty tough surface for the string ball ends to bear against. With the final step of slotting the bridge pin holes rather than using slotted pins, which seats the ball ends firmly against the solid plate surface rather than against the edges of the holes, this bridge plate will be trouble-free for the life of the guitar.

[needspeed]

Originally Posted by Todd Rose

I don't believe a cloth patch really accomplishes this, so I've never really understood the reasoning behind the use of a cloth patch.

I am going with cloth is cheap and easy and better than nothing.

Thanks for creating this build thread. I really enjoy watching the builder and the build process. So far, so good, and I look forward to your continued updates......Steve