Thursday, August 28, 2014

More Necking with Bruce! A perfect fit!

Just take a good look at how the buildmyguitar project looked at the end of the day Thursday.

I think this guitar is lovely. I can't wait to play it. That should be maybe late next week, or certainly the week after that.  It took a good deal of time Thursday to get the neck set into the guitar properly, and I now know why Bruce's long experience at fixing and building guitars adds so much value to the instrument.
My guitar with the neck set

This is about the most important part of the project as far as the playing condition of the guitar is concerned. The neck does a lot of work and it has to be set just right to make certain everything lines up properly. There is only one way to do that, get out your chisels, put on your glasses and put the neck on and take it off about a half a million times or so. (Actually, about a dozen times. But it took a long time to do that.)

It's not actually a geometric formula that defines all of this, but you do have to think of the neck at work on a couple of different planes. Let me explain. First, it has to sit under the string just right so they can be toned properly. Just a hair off and that E won't sound so good when you move up the neck to G and A and beyond. And that's just one string. All six have to be sitting the right way.

How hard could that be?

Take a look at the working end of the neck.

Checking the angle on the face of the neck
What you are seeing is the end of the neck, the tenon joint, the bolts that will hold it firmly in place and the small aluminum legs Bruce installed to make certain the fingerboard (that's the dark brown piece that faces up) fits tightly against the top of the instrument. A lot of guitar builders and companies glue all of this into place. But a couple of decades of guitar repair led Bruce to this system, which, once it is in place, can come off easily and cleanly without damaging the surface of the guitar.

The challenge now is to fit it properly to the guitar. It doesn't just stick in there. It has to sit at the proper angles vertically and horizontally so the neck is in the right alignment with the bridge, where the strings hook to the top of the guitar. The only way to do that is to put it in place, see what happens, measure all of those different planes and then take a chisel to whatever part needs to be cut down to improve the fit. Bruce will actually back cut around the tenon, from the sides inward, to make that part of the neck a little concave.

Trimming away another slice to improve the fit
It's a pretty physical job and it takes a good deal of wood away from the edges that fit against the guitar. You want the outside of the neck edge to fit tightly against the body, even as the inside of that edge is concave from the carving so it will fit right. It seems to me that it would take roughly a dozen guitars built and working well just to get into the swing of it. Bruce has built lots more than that. So he keeps slicing away and putting the neck back in place to see how it fits. This is the perfect time to have a good talk about old girlfriends, embarrassing moments and a couple of other things that should be in a completely separate blog about the wonders of aging! But it does kill a little of the time. If you are not actually doing the work, this is kind of boring. If you are doing the work, I suspect, its a little scary because it has to be right. A beautiful guitar with a bad neck set will be good for hanging on the wall and not much more.

Using a string to check the set

This is what Bruce uses to check whether the neck needs to shift left or right. It's a sophisticated piece of equipment I would call, "An old piece of string!" He does this on both sides of the neck. There is a separate tool, a piece of straight wood with a little heel on it, that lets him check the "action" (how far the strings will be off the fingerboard) and how high the saddle will be on the bridge. Watching the process, it's easy to see that he has to take a little wood off of the left side of the base of the neck to move that string a little toward the center. The problem is the same on the other side of the neck, but the adjustment needs to move the string a little toward the outside of the neck.

There is no simple way to describe how to do this. Bruce (and all good guitar makers) use their eyes and their experience in trying to figure out how much to slice away. It's kind of unnerving because my typical mistake would be to slip with a chisel and put a deep gouge someplace it should not be. Bruce doesn't do that. Not at all in fact. He is confident and specific about what he wants to remove, does just a little at a time and constantly checks to see what effect the trimming had on the set of the neck.

At one point in the process,  Bruce found an irritating squeak when you shifted the neck in its groove and traced it to one of the holes in the body that the bolts in the neck pass through. He attacked with his chisel, making the round hole a little oval to solve the problem. I commented that this process must take a lot of patience and Bruce said it wasn't about patience, it was about building the guitar right. There are reasons why so many steps evolved in this process, and this is one of the most important. It's one place where it pays to be fussy.

Looking at string and bridge height, all a function of the set of the neck.
After a good two hours of trimming, removing and replacing the neck, Bruce affixed the two nuts to the bolts that hold it all in place, tightened them down and it all pulled together quite nicely. This means there is not much work left to do before we can string it up and play it.

Eyeing the neck set
It's all looking good, Bruce says at the end of the session. Next week, we cut the slot for the saddle, make the holes big enough to hold string pegs and put the final touches on the headstock of the guitar. We're thinking a piece of copper should cover the adjusting rod. That will match the copper strap that will go across the top of the guitar.

Come back, please. I'll play something for you before you know it!

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