Neck Angle Calculations

[lucky1]

Edited September 19, 2004 by lucky1

[rhoads56]

Draw the body thickness at the bridge, then add the bridge, drawing it mid way through its adjustment (so you can go up and down). Draw any relevant carving depths, add the thickness of the fretboard (in the centre, not edges) at the neck/body join, and draw the fret height, and string height.

Draw a line from the bridge, through the "action height at body join", all the way out to the approximate nut position. Measure the scale length, draw in the nut, with the string sitting where it would once the nut is slotted, then draw the fretboard (with fret height).

[Setch]

Perry's technique is pretty much foolproof, you'll do fine if you follow it.

I do it a little different, but the end result is the same:

I draw a line which represents the body. I mark the body end of the fretboard, and the bridge on this line. I measure the height of the bridge adjusted all the way down (in the centre if it's radiused like a tunamatic). I measure the thickness of the fretboard plus frets, as Perry said, in the centre. I subtract the thickness of the fretboard plus frets from the height of the bridge, and mark this height at the bridge location. A line from the top of this mark to the end of the fretboard mark will show you the neck angle.

You also need to decide whether you plan to shave the body down to create the neck angle, or raise the end of the fretboard. My method above is for the first technique. If you are going to raise the fretboard, you need to mark the point where the neck joins the body, not the end of the fretboard.

To address the specific questions:

1. I mark out the string height as if will touch *all* the frets between nut and bridge. This way you can always adjust up to achieve good action, rather than being tied to whatever action you chose on paper.

2. See above - You can dial in the height of the bridge an nut when the guitar is completed, so shoot for an action of 0 when building.

3. I measure it bottomed out. Perry measures it halfway up. So.... take your pick - I'm confident that Mr.O' knows what he's talking about, and I know my method works for me.

4. I mark everything using the scale length uncompensated, since any compensation I mark would only be a guess. If you're building a guitar you've built before you can make an educated guess, but that's still what it is. Do what you feel comfortable with, I don't think it will make or break the guitars action.

[rhoads56]

3. I measure it bottomed out. Perry measures it halfway up. So.... take your pick - I'm confident that Mr.O' knows what he's talking about, and I know my method works for me.

I guess i dont really measure it with the saddles halfway up, more that if the saddles are all the way down, then the string would hit the last fret. I guess you are saying the same thing.

[RAI6]

I measure the height of the bridge adjusted all the way down.

I measure it bottomed out. Perry measures it halfway up. So.... take your pick - I'm confident that Mr.O' knows what he's talking about, and I know my method works for me.

The drawback to basing your measurements on everything being "bottomed out", is that if something goes slightly wrong and you would need to adjust down, you're already there...

I would rather go with putting things centered/midways, so that there's a little room for adjustment/errors...

[metallisomething]

for determining the neck angle couldn't you just make a imaginary triangle with the bridge, strings, and guitar body: the height of the bridge (all the way down, middle, all the way up, your choice) is one side of the triangle, the length of the strings is the hypotenuse, and an imaginary line perpendicular to the bridge that goes to the end of the strings is the third side

now you have a right triangle. you can use a trig function to find the angle, you dont even need the "imaginary" line

x = neck angle

cosine x = bridge height / string length

i think this would work

[lucky1]

Edited September 19, 2004 by lucky1

[rhoads56]

for determining the neck angle couldn't you just make a imaginary triangle with the bridge, strings, and guitar body: the height of the bridge (all the way down, middle, all the way up, your choice) is one side of the triangle, the length of the strings is the hypotenuse, and an imaginary line perpendicular to the bridge that goes to the end of the strings is the third side

now you have a right triangle. you can use a trig function to find the angle, you dont even need the "imaginary" line

x = neck angle

cosine x = bridge height / string length

i think this would work

You havent allowed for the desired fretboard height, OR depth of carve (if any). Thats why you need to draw it. A simply drawing will take ten minutes, that is accurate enough for what you want.

[metallisomething]

ok ok fair enough i didnt think of that

in that case could you just take the height of the bridge and subtract the desired fretboard height?

[rhoads56]

ok ok fair enough i didnt think of that

in that case could you just take the height of the bridge and subtract the desired fretboard height?

Huh??????????

Just draw it out

[SonofaMesa]

I just did my SG style guitar and I only get an angle of about .5 deg. The bridge height is about 5/8 in the middle (standard Gibby) and the frets+fretboard is 5/16. The angle seems pretty low. Is this possible?

[litchfield]

Yeah. That actually sounds steep to me.