F212XL neck reset

Rob Reilly

Junior Member
Joined
Aug 6, 2017
Messages
28
Reaction score
30
Location
Indiana
New member, first post.
I recently bought a 1973 F212XL Westerly 12 string jumbo body.
The seller was very honest with his description and said he thought it needed a neck reset.
This was allowed for in the price.
The top was bowed below the bridge and the "action" was indeed a little high.
I gave it a thorough humidification with damp sponges in plastic baggies inside the sound hole, with the strings loosened, for about a week in a closed case.
With this treatment the top flattened out pretty well.
I adjusted the truss rods (yes there are two).
It plays very nice now.
I'm thinking it no longer needs a neck reset.

I have read several threads on this forum about neck resetting, but mostly they concentrate on cost and finding a luthier.

Question for the experts: what measurements can I take on the neck, and what parameters define the need for a neck reset?
Don't be afraid to blow me away with detailed instructions. I am a professional mechanical engineer and am familiar with precision measurement, have micrometers etc.
 

fronobulax

Bassist, GAD and the Hot Mess Mods
Joined
May 3, 2007
Messages
24,708
Reaction score
8,836
Location
Central Virginia, USA
Guild Total
5
Welcome.

http://www.frets.com/FretsPages/Musician/Guitar/Setup/NeckAngle/neckangle.html is one article I seem to recall having read before that talks about measurements. I know there are others but the Google-Fu is not strong in this one today. There are also several posters who are luthiers and they are pretty good about discussing what the measurements mean.

You might not get a clear answer on parameters, if only because if the owner thinks the instrument is payable and plays it, then it doesn't "need" a reset.
 

chazmo

Super Moderator
Joined
Nov 7, 2007
Messages
25,473
Reaction score
7,131
Location
Central Massachusetts
Truly excellent idea/strategy to humidify the guitar and see what happened. Cool. Just a note, if your soundboard got kinda out of shape before you hydrated, you might find that one/some of the braces has separated. You should have a look at that and if any have you can re-glue them and prevent future issues.
 

Christopher Cozad

Senior Member
Platinum Supporting
Gold Supporting
Joined
May 11, 2010
Messages
2,415
Reaction score
1,429
Location
near Charlotte, NC
Welcome to LTG, Reilly, and congratulations on acquiring your 12 string.

Frank Ford's article, linked to by frono, above, should give you a general idea of the metrics involved. I would add that the only purpose of the truss rod (or, in the case of your Guild 12 string, two compression rods) is to control what is called "relief" to the fingerboard. This is a very slight, but deliberate, forward bow in the neck that introduces additional clearance for the strings to vibrate freely without rattling (buzzing) against the metal fretwires. Check for and/or set this relief prior to trying to determine the relationship between the neck and body planes.

Adjusting the truss or compression rod(s) affects string height but should not to be used to adjust string height (action). Assuming the plane of your fingerboard is relatively flat (not unduly warped or twisted), and with the guitar tuned to pitch, depress the first string in two places simultaneously: at the first and fourteenth frets. There is a minor dexterity technique involving the use of your pinky on your dominate hand to hold the string down, in order use your thumb to tap the string at the sixth fret - the middle point in between the two outer points. This is where relief is measured. You are looking for some clearance, be it 0.001" up to 0.020", depending upon your playing style. More clearance is required for more aggressive picking/strumming without string buzz. The compression rods in your Guild have each been secured into a concave groove, permanently affixed into the heel of the neck and emerging free into the recess routed into the headstock. (Gently, carefully) tightening the nuts in that recess compresses a washer against the wood at the headstock and attempts to straighten the metal rod, thus bowing the neck backwards slightly. Loosening those nuts allows the string tension to pull the neck forward, slightly.

Assuming the bridge is properly secured to the soundboard, and is not lifting away, verify that you have 0.3125" up to 0.375" of bridge height (for posterity: 5/16" to 3/8"). A bridge measuring lower than 5/16" typically indicates it has been planed down in an intervention attempt to stave off a neck reset. With the saddle projecting from 0.125" to 0.1875" (1/8" to 3/16") above the bridge, you are looking for a bridge/saddle combined height of approximately 0.5" (1/2") off of the soundboard. If the bridge has been planed and the saddle has to be extended in order to achieve that target height, in addition to the risk of splitting the bridge in front of the saddle, your intonation will be compromised, as the saddle bends forward under the strain.

If you use the straightedge test, set the neck relief first, and then verify you have sufficient bridge height. Then you can lay a straightedge down the length of the fingerboard, across the frets and out onto the bridge in order to determine if the neck and body planes are aligned properly (see the article).
 

Cougar

Enlightened Member
Joined
Nov 28, 2015
Messages
5,323
Reaction score
3,016
Location
North Idaho
Guild Total
5

Rob Reilly

Junior Member
Joined
Aug 6, 2017
Messages
28
Reaction score
30
Location
Indiana
Thanks Fronobulax, Chazmo, Christopher, Cougar and Killdeer.
That website frets.com is excellent. I sat up half the night reading it.
Initial 24" straightedge measurement indicates the bridge is 12/64" above the frets.
Looking inside with a lighted mirror, I do not see any brace separation.
I put a tiny drop of oil on the truss rod nuts.
I don't think I can post any pictures until I am out of the novice category.

The musician thinks the instrument is playable and plays it.
 

adorshki

Reverential Member
Joined
Aug 21, 2009
Messages
34,176
Reaction score
6,791
Location
Sillycon Valley CA
Initial 24" straightedge measurement indicates the bridge is 12/64" above the frets.
The musician thinks the instrument is playable and plays it.
Welcome aboard, Reilly!
Are you saying the straightedge test shows the straightedge falling 3/16 (12/64) below the crown of the bridge? (Not Good, sounds like it's been shaved below the ~5/16 ideal height)
OR do you mean the bridge height from top of guitar is 3/16" inch? (also not good, but if you deducted the height of the fretboard from the bridge height that would explain it.)
Bridge height should be measured from top of guitar at high point of crown and saddle height added to it to get the ideal 1/2" bridge and saddle combined height that Cristopher mentioned.
Fractions of variance in the neighborhood of 1/32" aren't cause for concern, in fact my '04 D40 is a full 1/6" taller than the "ideal", but I suspect it's because it has a factory installed under-saddle transducer so a bridge with a bit more mass than usual was used.
 
Last edited:

adorshki

Reverential Member
Joined
Aug 21, 2009
Messages
34,176
Reaction score
6,791
Location
Sillycon Valley CA

adorshki

Reverential Member
Joined
Aug 21, 2009
Messages
34,176
Reaction score
6,791
Location
Sillycon Valley CA
Ah, pesky details. We talks in sixths, and we knows what we means betwixt us. lol

You can talk in sixths if you want, I'll stick the the aforementioned fifths.

eb051d78036ab491e984a657c7428307--whiskey-bottle-liquor-bottles.jpg
 
Last edited:

Rob Reilly

Junior Member
Joined
Aug 6, 2017
Messages
28
Reaction score
30
Location
Indiana
You are quite right that the bridge saddle has been shaved down too much.
There is a tiny string buzz on the high E when I play F through G#.
String to 2nd fret clearance is about .008" when I play F.
The next 3 notes about the same measured under the next higher fret.
I have a bone saddle blank.
I'll make a record of all clearances before I start making a new bridge saddle.
 
Top