New neck machining process

So I’ve spent most of this week developing an improved neck machining process, refining the design of the necks to correct a couple little things which have bothered me about them, and developing a new “long neck” neck variant that results in bridge position more like the “Ms. Griffith” Loar A-5. I don’t know if it’ll work great, or not really do much to the sound, so I’m only trying it on Kris’s #24. I approximated it as well as I could on #13, as a test, and it wasn’t night and day, but it was a noticeable difference. A little more percussive.
Came up with a new headstock to go with the long neck, to help out the visual balance a little bit. I think I’m going to use this headstock shape on #26, as well.

Anyway, here’s the new vacuum fixture. It’s very frustrating to work with vacuum, because if you have even a microscopic leak, the part won’t seal at all. It’s all or nothing. For the first few cycles I run on a new fixture, I’m biting my fingernails because if it breaks loose, it’s going to fling across the room at high speed.

But I finally got the seals worked out, and here’s the gauge reading 20 inches of mercury. So with about 20 total inches of surface area, that’s like a couple of full-grown men standing on top of the part. It’s not going anywhere.

First pass is roughing, then a finish pass, and the part gets flipped onto the vac fixture.

[IMG]https://lh6.googleusercontent.com/-Bh99oom0iKI/UcN-am201FI/AAAAAAAAluU/6EYwxrWc1z0/s1000/20130620-IMG_1222.jpg[/IMG]

The result is very clean, and almost polished, in most places. This is the neck for #24.

The best thing is that the new code dances around the direction of the grain. I have never gotten clean corners right off the machine on mahogany before. They always blow out a huge chunk of wood, and require significant sanding in order to be cleaned up.

That’s the neck for #25.

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