When Stratocaster Nuts Drive You Nuts - Keeping The 6-Screw Fender Tremolo In Tune:

Inspector #20

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I wrote previously about my difficulties with my YelloStrat tuning issues, specifically that it went sharp after every tremolo bend.

The Warmoth neck came equipped with a Graph Tech Tusq XL nut that was CNC machined. The slots measured .047, .037, .027, .017 .012 & .010 - exactly .001" wider than the strings and cut parallel to the fretboard.

Here's the neck as delivered:

20210225_141146.jpg

As one might expect, I had tuning issues. Most articles say the nut slot should be no more than. 002" wider than the string. Ok, I had that. Other articles said to.polish the other and I did that too, but it still went sharp on dives...even shallow ones.

Another issue with the short, vintage tuners was the angle on the low 'E' was quite extreme. This is due to the relatively short post on the hollow shaft tuners:

20210308_065735.jpg

I cut each slot downward towards the tuning keys. The notch in the neck is not from filing. It is from me pushing down on the string behind the nut.

No matter what I tried, the low 'E' would go sharp by 4 or 5 cents everything I would release the bar. Fretting and bending a note would return to pitch.

My local tech - 30 years with Fender - agreed to setup YelloStrat but wanted $200.00 to do it. He also told me,, " The Gotoh (SD-91) tuners are cheap, Jap junk. You need to get them off of there."

That statement really turned me off. I think $200.00 is certainly fair and about the going rate here in SoCal for a full setup, but then, i decided against it, because I could buy a brand new, yellow cream Fender hardtail body from a mutual friend for $100.00, and a Gotoh hardtail bridge for $40.00 and solve the problem permanently.

Tonight, I decided to conduct a few experiments. I attached a dial indicator to my headstock and checked each tuning post for movement.

When I press my tremolo bar down to the pickguard, I can drop 11 semitones to D#. If I pull up, I can raise my 'g' string to b flat. This works out to the Fender spec of the bridge plate being 3/32" off the body.

Not one tuner showed any movement, forward or backwards.

Then, I started examing the strings as they moved through the nut under magnification. Sure enough, the low 'E' was hanging up.

I took the low 'E' slot out to .049" and the string still hung up in the nut. Then I remembered an article about nuts written by Paul Hostetter. Paul said the nut slot needs to be "funnel shaped" in order to guide the string, but not bind it, with only about the front most 2/3 of the nut contacting the string.

Paul posted these diagrams to illustratehis point:

picard.horn.3.jpg

picard.horn.4.jpg

I started by opening the low 'E' slot with a .052" round file. I then angled the slot down towards the tuning keys. The idea was to alleviate as much string pressure as possible on the nut.

20210308_190030.jpg

Next, I opened each slot to form a "double bell" shape. The low 'E' has the largest bell and each successive string has a smaller bell shape.

20210308_185924.jpg

I retained my setting of .020" at the first fret:

20210308_190221.jpg

Guess what??? Zero tuning issues after 15 all-the-way- to-the-pickguard dive bombs.

Interesting!!!!!
 
Great work! I would have said more simply that the low E, and your other strings, are too low in the slot. About half the diameter of your wound strings should be above the nut. As for the unwound string, they still show not be down too far.

I notice most of my hand crafted guitars are cut that way, except PRS. They must depend more about the slipperiness of the nut material, probably like graph tech does.



nutslot7.jpg

nutslot4.jpg
 
Lube your nuts.
It's fun and enjoyable.
Especially on bone or dare I say it, plastic nuts.o_O
But Robert speaks the truth. Funnel shaped nut slots and a generous fall away, help a tremendous amount at relieving wound string hang up.
Taller string trees help as well, as we're looking to eliminate as much friction as possible over the nut.
A big plus is also paying mind to the number of string wraps around the tuner post.
I like no more than three, that way when you dive the bar there's less chance of unravel.
 
Great work! I would have said more simply that the low E, and your other strings, are too low in the slot. About half the diameter of your wound strings should be above the nut. As for the unwound string, they still show not be down too far.

I notice most of my hand crafted guitars are cut that way, except PRS. They must depend more about the slipperiness of the nut material, probably like graph tech does.



View attachment 60902

View attachment 60901

I could sand the top of the nut down to give what is shown in the photo, but once it returned to pitch, I just left it alone. I think it may also help me since I am not using string trees.
 
Lube your nuts.
It's fun and enjoyable.
Especially on bone or dare I say it, plastic nuts.o_O
But Robert speaks the truth. Funnel shaped nut slots and a generous fall away, help a tremendous amount at relieving wound string hang up.
Taller string trees help as well, as we're looking to eliminate as much friction as possible over the nut.
A big plus is also paying mind to the number of string wraps around the tuner post.
I like no more than three, that way when you dive the bar there's less chance of unravel.

Good points. I'm not using string trees at all on this guitar and thus far, no strings are popping out of the nut.

Now, on vintage tuners, I like two wraps on the wound strings, but prefer about 4 to 5 winds on the plain strings which seems to add a little light downward pressure in the nut.

I have roller string trees on hand. I am just hesitant to use them...
 
@RVA - I have found that creating a more generous oversized slot works better. In this case, with a .046" string, opening the slot to about .052" was when the tuning began to start returning to pitch.

Now, while this may seem like a lot, keep in mind that Gibson's published spec for the low 'E' nut slot is .070" with a .046" string, so I'm quite conservative at a .006" oversize.
 
One trick I was shown is that on the tremolo itself, only really tighten down the two outside screws.
You don't leave the others loose, just snug down the two outside.

It's a little thing, that seems to contribute to the overall tuning.

Of course totally agree with the nut prep, huge part of this issue.
 
One trick I was shown is that on the tremolo itself, only really tighten down the two outside screws.
You don't leave the others loose, just snug down the two outside.

It's a little thing, that seems to contribute to the overall tuning.

Of course totally agree with the nut prep, huge part of this issue.

I use a different approach that Fender uses on the bench. It was shared with my by a 30 year Fender retiree:

1. Remove strings

2. Loosen all bridge screws

3. Tilt tremolo forward until the "slant cut" on the bottom of the bridge plate is resting flat on the body.

4. Tighten all 6 screws evenly until the underside of the screw head just touches the bridge plate.

Oh!!!

Another thing...I have long questioned Carl Verheyen's use of an angled claw on Stratocasters.

To me, changing spring tension along a fixed point made no sense, as the bridge block will not impart a different tension across its length because of where the entire unit pivots is immovable.

However, I did try it and it made no difference. I am using 3 genuine USA made Fender springs arranged in a | | | pattern.
 
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