Official Luthiers Forum!
http://w-ww.luthiersforum.com/forum/

Acoustic dreadnought neck geometry
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=55812		 Page 1 of 1
Author:  guitarjtb [ Thu Aug 03, 2023 9:01 am ]
Post subject:  Acoustic dreadnought neck geometry
What do you shoot for, with the fret plane, on the final set up of an acoustic dread, when strung to standard pitch? In other words, with the guitar strung to pitch, and a straight edge laying on the center line of the frets, theoretically, how much clearance do you want between the fret crown and the bottom of the straight edge? In my example below, I have assumed that the straight edge would rest on the top of frets 1 and 15. I assumed 003" relief at the 7th fret, .010" fall away to the last fret, and just filled in the rest. I know you are not measuring to get these clearances, but in theory, what fits the way you want to level the frets? Excuse all the astericks, but spaces were not recognized by the OLF software.
Fret # ****Clearance
1 ******* .0000"
2 ******* .0003"
3 ******* .0005"
4 ******* .0010"
5 ******* .0015"
6 ******* .0025"
7 ******* .0030"
8 ******* .0025"
9 ******* .0025"
10 ******* .0020"
11 ******* .0015"
12 ******* .0010"
13 ******* .0005"
14 ******* .0003"
15 ******* .0000"
16 ******* .003"
17 ******* .005"
18 ******* .007"
19 ******* .010"
Author:  SteveSmith [ Thu Aug 03, 2023 9:36 am ]
Post subject:  Re: Acoustic dreadnought neck geometry
0.003" is not bad for relief at the 7th if the fret board is properly leveled, I don't measure it anymore but I don't put in anymore than on the treble side except for the rare guitars where it is needed. I level the board by supporting the neck at the 7th fret and then varying pressure on the headstock so that there is more relief on the bass side than the treble side, the result is the bass side might be around 0.010" when the treble side is near 0. Again, I don't measure these things anymore.

I do fall away starting at the 12th fret. I don't measure fall away, I just put masking tape on the leveling bar to hold it higher while it rides on the 12th fret, mark the tops of the frets and then sand until the marker is just starting to be removed on top of the 13th.
Author:  guitarjtb [ Thu Aug 03, 2023 10:18 am ]
Post subject:  Re: Acoustic dreadnought neck geometry
SteveSmith wrote:
0.003" is not bad for relief at the 7th if the fret board is properly leveled, I don't measure it anymore but I don't put in anymore than on the treble side except for the rare guitars where it is needed. I level the board by supporting the neck at the 7th fret and then varying pressure on the headstock so that there is more relief on the bass side than the treble side, the result is the bass side might be around 0.010" when the treble side is near 0. Again, I don't measure these things anymore.

I do fall away starting at the 12th fret. I don't measure fall away, I just put masking tape on the leveling bar to hold it higher while it rides on the 12th fret, mark the tops of the frets and then sand until the marker is just starting to be removed on top of the 13th.

Thanks for the info. That will leave the 13th fret very close to the height of the the 12th. I have always done fall away from the 12th fret also. This example varies from what I do just a little. I don't have a way to measure either. Just feel and magic markers. :)
Author:  SteveSmith [ Thu Aug 03, 2023 10:25 am ]
Post subject:  Re: Acoustic dreadnought neck geometry
13th fret needs to be relatively close to the 12th or it won't play right. I have the measurement tools and used to measure what I did but having done so many I don't anymore.
Author:  jfmckenna [ Thu Aug 03, 2023 10:34 am ]
Post subject:  Re: Acoustic dreadnought neck geometry
I don't measure either. I've tried using feeler gauges but I don't see how it's possible to have that accuracy with human hands and strings that so easily bend. I just eyeball it. But those numbers sound right to me except I don't do fall away on acoustic guitars.
Author:  Ken Nagy [ Thu Aug 03, 2023 3:02 pm ]
Post subject:  Re: Acoustic dreadnought neck geometry
I just had,trouble with buzz on.my.cello. The A (top string) needed ".06" scoop, a little past where the 7th fret would be, at the neck join. The low C, below the low guitar E worked with maybe .05", they recommend .05 and .08. The difference is that even though the A is stiffer, the C is .280" above the fingerboard (at about the 30th fret) and the A is lower at .20 above.
Different animals. Even a violin has .02-.04" scoop.

You guys are measuring TENTHS! I didn't even like turning hardened steel tools on the CNC with +0005 -.0000 tolerances.

I just measured my guitars. I never did before. I bought a carpenters square? to get a long flat edge. .016 or so on the nylon strung Stauffer and that much from the 3rd to the 10th fret on the archtop. That one has a truss rod. I could move it.
Author:  Hesh [ Fri Aug 04, 2023 4:04 am ]
Post subject:  Re: Acoustic dreadnought neck geometry
How it's done is relief is adjusted with the truss rod, nut slots are cut as the final, low cut and then action is measured at the 12th fret. Point being and this is important the 12th fret action measurement is taken AFTER other things have been addressed or, in other words there are dependencies here.

In our shop we use inches and fractions and decimals because that's what our customers understand where we live.

Martin has set-up specs that I use and that guide me. Our business very early on made the set-up a very big deal because I contend it's the human interface to the instrument and nothing can be more important.....

So with the above in place, truss rod and neck adjusted for minimal relief on the treble side and more relief on the bass side if the neck has more relief on the bass side, 50% of the time they don't. And with the nut slots cut to the final, low cut we measure at the 12th and set the following to the following. Also these are some of my specs there are many more AND individual players OF COURSE have bearing on this. If I know Ryan to be a heavy hitter with tens I go higher to accommodate.

Acoustic:

12's 12 fret action high e 4/64th" low e 6/64th" this is for a dread and a generic player further adjustments are player specific
13"s 12 fret action high e 4.5 - 5/64th" low e 6 - 7/64th" also for a dread.

Smaller bodied finger style guitars <4/64th" high e 5 - 5.5/64th" low e

Mandos are also set at the 12th

3/64th" or less high strings and 3.5 - 4/64th" low strings and sometimes lower. I've done mandos at 2 - 2.5... but the fret work was perfect. We always say the treble side first too so 2 - 2.5 means treble side 2/64th" and 2.5/64th" on the bass side.

12 string acoustic: <4/64th and >4/64th they are OK a bit rattly

Electric Gutiars:

10's 4/64" or less high e 4.5/64th" or less low e. This goes up and down with the attack of the player.

shredder action for very light touch and/or some jazz players, requires perfect fret plane: 3/64" and 4/64" give or take some

So with what I just shared some will recognize is pretty valuable... and a slice of the commercial world that most importantly makes folks happy, is possible and has worked for all concerned. Again the fret work must be good for these numbers to be possible in some instances.

You also can see that the other frets and measurements are useless and will not get us where we want to go. Why the 12th fret? It's the center of the "speaking length" of the string.

I buy a lot of guitars and see other people's set-up specs too and I'll take mine thank you.... and mine are not mine again these are industry specs that for those of us who share with other pro luthiers are not uncommon to use.

So the action gets progressively higher as we move down the neck to the body.

Fall-away starts around the 12th and when I was building I took Mario's guidance and shot for .010 - .020" fall-away measured at the last fret and in respect to the 12th fret action. What's most important if someone goes the fall-away route is not to have any kick-up or ski ramp at the end of the fret board. Shredders are not going to want fall-away and bluegrass pickers are. So fall-away is also somewhat of an individual thing.

I added fall-away to all the acoustics that I built and am glad that I did. I would not add it to a shredder guitar but I would add it to a generic Strat player.

Guitars most likely to develop the ski ramp are Fender style bolt on necks.

Lot here hope this helps.
Author:  Hesh [ Fri Aug 04, 2023 4:06 am ]
Post subject:  Re: Acoustic dreadnought neck geometry
Bet you never saw fractions and decimals combined either as in 4.5/64th" :) But it's how we communicate in our shop, our language if you will and it makes perfect sense to us.
Author:  Ken Nagy [ Fri Aug 04, 2023 11:56 am ]
Post subject:  Re: Acoustic dreadnought neck geometry
Well my relief is about 1/64" Tightening the truss rod that is where it goes. The low E/high e is 5/64 and 3/64 on a 14 fret archtop with 25.2" scale and 80/20's that measure at .010".

The .016 relief doesn't seem like much. But it is 5 times a 3 thou relief.
Page 1 of 1 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/