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I'm thinking about buying, or making a neck jig, but I'm not sure how to use it.

As I understand it, it's used to support the neck, and hold it in place when the strings are moved, so that it keeps the exact shape as if it had the strings on.

But when the strings are off, are the frets supposed to be leveled straight while the neck is in this position?

When I have strings on my guitar, the neck has a slight bow, so that if I press the string down at 1st and 22st fret, there is some room between the string and the 12th fret.

But if the neck is fixed in this position when the strings are removed, and I use a file or sanding block to level the frets, won't I ruin that slight bow?

I'm having some trouble understanding why it should be done that way. I would think that the neck should be completely straight when the strings are removed and the truss rod are loosend, but not when the trus rod is tensioned and the strings are on.

Can anyone help me?

Tommy

Tommy, I don't use one of these yet and I have to assume that your talking about Dan Erlewine's neck jig right?



Have you checked out the instructions for use on the Stew Mac site?

Neck Jig, Instructions hope this will help some.

I'm pretty sure that Tim McKnight uses one similar, hoping he will chime in here.

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You adjust the neck so it's as flat as possible with the strings on (ie, tweak the truss rod), clamp it all up so it won't move with the strings off, then go for it.

I liked what I think Rick Turner posted once: string up the guitar, tune to pitch, set the neck as straight as you can get it, then use some angle iron with sandpaper glued to it to level the frets under each strings, while tuned up. Then take the strings off, recrown, polish, done. Voila. No Neck Jig needed! Note: I've only done this once, but it seemed to work...

Ok.. I thing I got it now. The whole point of the jig is to be able to straighten the neck, without adjusting the truss rod.. that makes more sense.

But how do you measure that the neck is dead straight before you start sanding/filing the frets... By using a straight edge...or your eyes?

Tommy

No, the point of the jig is to simulate string tension with the strings off. That way you can work on the neck and get accurate results once the strings are back on.

And, no, you absolutely have to have an accurate set of straight edges. Usually one long enough to measure the entire fretboard, an even longer one to check the bridge height, a small one to "rock" on the frets to check their height when dressing them, and a notched one is nice too to check the board as you are adjusting the truss rod.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

ok..

But if you want to simulate string tension, with the strings off, that means that the neck will have a sligt bow while in the jig, just like it has when the strings are on.

How can you level the frets if the neck has the same slight bow that it has when the strings are on?

On the erlewine instructions page it says:

" The guitar neck remains free, as the Neck Jig and guitar are tilted toward 90 degrees into the “playing position.” Here, with the strings tuned to pitch, the neck is adjusted (usually straight) for the type of fretwork you are about to do."

Seems that the neck should be adjusted straight before removing the strings..?

Tommy

The neck is adjusted to straight with the strings on in the jig, and there are supports that fit under the neck after you get it straight so when you take the strings off the neck stays exactly like it was with the strings on. This is the simulated string tension.

Make sense? It is hard to explain.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

The most important feature of the neck jig is simply that it holds the neck
in position while being sanded or filed, whatever position you decide is
appropriate. You can set the instrument up on the jig with the neck
straight, or you can set it in relief and then manipulate the rods from
there to raise or lower areas which you want to remove more or less
material. Then it holds the neck in that position while you sand or file.
Bass necks will often move .030"+ at the nut between horizontal and
playing position just from gravity on the headstock, and in the process of
pressing a file up and down the neck you will movie it even more.

Another thing to remember is at the time this tool was first made
adjustable truss rods were a very new thing on Martin guitars. If the neck
was straight or in moderate relief under string tension, then it would be
in backbow when the strings were off. The old way to straighten and
simulate string tension was to support the end of the neck in a cradle and
put about 8-10 pounds of weight on the shoulders. Even the early
versions of this jig were a dramatic improvement from that. The neck jig
is a wonderful tool for dealing with non adjustable truss rods or necks
that are in backbow when the strings are off.

I don't use mine on all fret dresses, but mostly on problem or squirrely
necks. I did use it on all fretboard levelings and fret dresses when I was
building though, and has really proved invaluable at times. The most
important thing is that it holds the neck where you want it while leveling.
The dial indicators are wonderful to help understand and monitor
changes in the neck position as adjustments are made. Details of how the
neck should be adjusted however is really up to the judgement and skill
of the person using it.

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it is easy to reverse engineer one of these and build it yourself for $50 or less depending upon what you have handy in the shop. the most expensive items are the 6 flexible feet for stabilizing the platform and to serve as rests for the instrument(graingers), about $30 or so, and 2 dial indicators, about $14 from harbor freight or similar.

s-m used to sell a video on how to use the jig, and it is of particular value in accomplishing a number of repair work tasks. i have never had to use it when building.

Tommy, I have an early version I purchased from Dan Erlewine before they were available in the catalog. I use the neck jig any time I am leveling frets. The intent is to simulate string tension in the playing position. The rods are only there to support the adjusted neck, not to actually push it into any certain shape. My procedure goes like this: 1. Fasten the guitar into the jig. 2. Rotate the jig, placing the guitar into playing position. 3. Tune the guitar to pitch and adjust the truss rod until the neck is straight (I usually use a notched straight edge to read the fingerboard instead of the frets). 5. When the neck is straight, set the dial indicators to zero, adjust the support rods against the neck, and rotate the jig back to the normal position. 6. Remove the strings. At this point the dials are going to move and you will use the peghead jack and/or the adjustable tie down strap (fits across the nut slot)to flex the neck enough to return the indicators to zero. The neck is now is the same shape as if it were strung to pitch, adjusted straight, and held in the playing position. I then level, recrown, and polish the frets. When finished you merely string the guitar and adjust the truss rod to the proper amount of neck relief.

Thanks, that makes sense.

I guess you could straighten it without touching the truss rod too...if that is important. However, if you level the frets, you'll probably have to adjust the truss rod after removing it from the jig anyway..

I got to get a good straight edge and some sanding blocks. I might try to make the jig myself..

Tommy

It's useful in a number of ways, and I do differ from Mark in that I do use
the rods to push the neck to where I want it to be. For example, if I am
refretting an neck with a non-adjustable truss rod, or one with an
adjustable rod that will not pull in to relief with the truss rod loose. In this
case I would set it up on the jig in playing position and zero out the dials.
Then with the strings removed I would push the rods in the center to read
about -.007" to -.010", while holding the end at zero by the nut. By
leveling in this position you will have sanded .007" -.010" relief in to the
board that will be there when it is strung up to tension.

This is a simplified version, and there are really a lot of other variables
that come in to play in setting it up. That example doesn't account for
fret compression, which will depend on the wire you're using, fretboard
material and the condition of the slots. It could also be adjusted if you are
doing this work for someone who wants to use light strings on a
dreadnaught, but you know it should be able to accommodate mediums
in the future. That's a brief example, but there are a number of different
scenarios where you may want to manipulate the playing surface and this
tool allows you to do it with greater control and precision than the
traditional free hand approach.

I made my own about 8 years ago based on the original neck jig we used
to use at the Guitar Hospital (Dan's old shop). The original one just had
rods to hold the neck in place, but we eventually replaced a few of the
rods with dial indicators which opened up a lot more potential for the
tool. I still prefer the jig to be built in to a heavy bench top hinged to
rotate at the center rather than the modern compact version. I'm sure the
new one is fine too, but I suppose I'm used to what I have.

David Collins39080.3342708333

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David, you are absolutely correct. There are instances where the rods would be used to assist a stubborn neck. I attempted to put a brief description together but am glad you pointed some of the other variables.