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I watched a PRS video today. After face milling the neck shaft they showed a closeup of the tuners being drilled. Anyone seen this fixture up close?

LOL, if the one in the video is the new one, I designed that fixture.

Trev

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http://www.PeakeGuitars.com

I'm all ears for your version

http://www.youtube.com/watch?v=jDhjKGF8e9w

At 1:39 you see the whole fixture. It looks like it could pivot at about where the heel starts and there looks to be an air cylinder underneath the center.

At 1:44 you see the holes being milled.

My problem would be it has to tip at an angle parallel to our nut which is 34 degrees from the perpendicular.

Yep, you got it. It's actuated with an air cylinder that is triggered using one of the M codes. PRS headstocks are in the neighborhood of 12 degrees. The old way was to use an angled head, but that thing was a pain to change....but for a 34 degree headstock that may not be a bad way to go. The one we used to use was speed limited. Using this jig we were able to eliminate a jig change and speed up the feed rates...good all around!

In all fairness, I took the idea from some jigs that a contract guy had made for PRS years ago (Eric Pritchard).

I hope that helps...!

Trev

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http://www.PeakeGuitars.com

I don't see any reason why the same concept could not be used on a neck with a 34 degree headstock. Depending on the machine of course. With a mill you would have plenty of Z axis travel to accomplish this. Let's see if you are doing a 25" scale with 22 frets that gives you a nut to 22 fret distance of approximately 18". So a triangle with a hypotenuse of 18" and at a 34 degree angle would give you a rise of about 10". Just about any mill large enough to fit a neck should be able to accommodate a 10" part, plus tool and fixture. If you are using a CNC router though your prolly not going to fit. So really it depends on your machine but I don't see why you could not make a similar jig and accomplish the same results.

I think Sheldon is talking about bass necks, but even so, they could be accommodated if he has a large enough working area.

Eric is a character, for sure...!

Trev

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http://www.PeakeGuitars.com

I see. Well even with a bass I see no issue. At a 30" scale you are still only looking at about 11 1/2" rise which should still fit in just about any CNC mill large enough to fit an entire neck in.

Wow, that's a crazy fixture. I love it.

I should clarify that our headstock angle is 10 degrees from the plane of the fretboard surface but because we do fanned frets, the angle of the nut is 34 degrees from perpendicular so the neck needs to be both tipped and tilted. Or at least the hinges would need to be at 34 degrees.

Trev, the fixture top looks pretty thick but it also doesn't look like it's made from solid stock. Is that correct? By the way beautiful work!

Hey Sheldon, Thanks! I really enjoyed my time there, and hopefully they don't mind if I share some of what I learned. I suspect they don't - guitar builders are a really gregarious group, even at the industrial level. We got tours from the Martin engineering folks when we visited them, and we of course returned the favor. Same thing with Taylor, Collings, etc.. I remember when we were planning our acoustic manufacturing line, and we were wondering how many man hours were in a Collings....so one of the guys called and asked! Not many industries willing to share that type of info...!!!

I want to say that the base is made from solid aluminum jig plate and the individual vacuum fixtures are indexed with precision dowels and bolted with machine screws. When you do that type of construction, you do need to use O rings on the bottom of the vacuum fixtures to seal them against the jig plate base. The vacuum comes in from the manifold on the right and enters the vaccum fixtures from the right side.

I hope this helps! I really like your instruments, great work!

Trev

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http://www.PeakeGuitars.com