Neck Extension Height Formula (Neck angle)

[Darryl Young]

Don, I'm glad you posted this. It's forcing me to think through a few things that came up a little off on my last build.

I just measured the fretboard I used on my last build and it appears it is less than 0.250" thick. Anyone know the thickness Martin uses for their fretboards? I'm guessing that is where my fretboard came from (John Hall probably knows).

Also, my pyramid bridge is thin........and got thinner when I sanded a radius into it. So you can't take the 1/4" fretboard and 3/8" bridge for granted.

[Dan Bombliss]

Make sure you measure you're fingerboard in the max of the arch, right in the center. Because of the radius it will measure lower on each side.

[turnertj]

Thanks guys! I really played around with it, and totally screwed up my neck, then got it back, then screwed it up, then fixed it! Without the fretboard I have a 5/32" gap to the soundboard now at the bridge location. Then with the bridge and fretboard on I have about a 1/16th clearance (maybe a bit less) at the saddle location.

BUT...I have huge gaps at my shoulders where I was unable to sand it correctly with the contour of the side. So, I came up with a fix which I think is kind of awesome. I'll post it in my build blog later tonight when I finish taking pictures...

Tj

[turnertj]

Here's where I landed with my neck set. I have a 5/32" clearance to the soundboard without the fretboard attached, and with the fretboard (non-fretted), I have about a 1/32" clearance to the bridge.

How's that?

Also, I'm about 1/8" off the centerline at the very bottom of the guitar. Is that too much, or good enough?

Thanks all...Tj

[Dan Bombliss]

If you already have you're bridge and fingerboard handy, you can just mock it up like you have there, and shoot for the settle in that you want.

The neck angle would be flush with the straight edge, from fingerboard and then flush to the bridge. If you're top pulls up (Settle in) then you're neck angle will be off by how ever much your top moved. So guestimating the settle in comes into play. My guess is that with the formula, with your fingerboard measuring a little under 1/4" and I rounded it up, is most likely the reason why you're 5/32" and it's still 1/32 lower than you shot for. Could be a combination of that and measuring a little on the safe side combined (my assumption).

If you have you're fingerboard and bridge on hand and mocked up, then you'd shoot for the settle in height above you're bridge. Meaning in the picture you just sent me, you're looking for 1/16" above the bridge.

The REASON as to why the NEH calculation is important, seeing as how the fingerboard and bridge mocked up solve the problem for you is that, when you want to get the perfect ramp in the soundboard to accommodate your fingerboard, for the smoothest look, you'll want to know that neck angle height.

So when I'm about to set my neck, I go through the formula for my NEH, and in you're case It was 5/32". So with that said, I mark out the saddle location on the top, and put a stack of 5/32" shims, and then take a sanding stick that rests on the stack of shims with sandpaper on the end of it. Then you can sand the landing on your soundboard from about the rosette to the edge, for your fingerboard landing to be same angle so no kinks or bends when you clamp it down to the top.

Because you can't just set your fingerboard into place with the bridge on it when doing this process, you need to know how high to make the shims with your fingerboard and bridge not involved at all in this equation.

Anyhow, long story short, with you're problem right now, you set everything in place like you did, and overshoot your neck angle by amount of settle in you want to compensate for.

-Dan

[tippie53]

Dan
I don't shoot for 3/8 without the fretboard that is to be 3/8 with the board and then with the frets you want to see about 1/16 inch off the bridge .
If I said that anywhere is was an error.
The exact number you should be looking for is .093 at the point of the saddle without the fretboard on the neck. That will get you pretty close , and you can adjust the bridge a little. Martin will use a number of bridge thicknesses . I do prefer a 3/8 bridge and will go down to .330 and not over .420
I have # 150 on the bench and this works for me . I agree that you all need to find the technique that works best for you , there are plenty of ways to do this.

[Herman]

On the guitars I made I aimed in the space John mentioned. And that works for me. All the guitars are in good condition. some of them have a quite low saddle, and none of them has a too high saddle. So my goal is not to aim at dead flat on the bridge, with the fretboard and frets on, but 1mm (about 0.04") above it.

Herman