D/A rattle problem at the nut?

[mercy]

When we file nuts its done my hand and sight I understand. It would seem reasonable that there would be some variability in the final product. How many thousandths difference from ideal doesnt matter. Im seeing that in the action at the nut on my guitar.
The reason Im asking is that Im getting a rattle on my D and G strings. The action at the 12th is good at 6/64ths for both of them. When checking the action at the nut the action of each string is different. I would have thought that they should be the same at the nut. I understand why there would be more action at the 12th to give room for string wobble but thats not an issue at the nut.
Is there some way for a tech to get the same action at the nut? Is that improtant? Do I need to have a new nut filed to get rid of the D/A rattle?

[charles Tauber]

Theory is that the height of all of the strings at the nut should be the same as the plane of the frets. In practice, some people like to allow a few thousandths of an inch more than that and to vary that amount by a few thousands of an inch from bass strings to treble strings.

If the "rattle" sound you have is due to the A and D strings being too low at the nut, those two slots can be filled with CA glue and baking soda or bone dust and then recut to the correct depth. (The symptom of a nut slot being too low is that the open string buzzes or rattles on the first fret.) Alternatively, one can shim the entire nut and recut all of the slots to the correct depths. Or, one can simply replace the nut and cut each slot to its correct depth.

One method that I like is to use a stack of feeler gauges that total the height of the first fret - or a few thousandths more. One then cuts/files to the top of the feeler gauges with the stack of gauges adjacent to the nut.

[mercy]

Thank you Mr Tauber,
I could fill with soda and I have bone dust and guages but its the round over toward the tuner post for the string to follow that I dont have the confidence to do.

[BradHall]

The round over is the easiest part of making a nut. You have the existing nut as a template if you want to make a new one or refurbish the existing one. If you decide you want to move foreword pm me and I'll send you a couple nut blanks to practice/learn on.

[runamuck]

Originally Posted by mercy

Thank you Mr Tauber,
I could fill with soda and I have bone dust and guages but its the round over toward the tuner post for the string to follow that I dont have the confidence to do.

The string should touch only the leading edge of the nut, or the edge of the nut closest to the first fret, and the angle of the ramp back toward the peghead isn't necessary to be absolutely the same string to string. What's important is the depth of the nut slot and that there be some ramping back.