Hello,

I installed an LSR roller nut a while back. I was checking and adjusting the setup/action yesterday and when i was satisfied happen to check the first few frets for tune accuracy. I noticed the 1st frets were sharp but seem to correct around fret 4. So i removed the Shims under the nut. This made a dramatic improvement but still a tad sharp. I plan on busting out a file and trimming down the wood underneath little by little til i get it in check.

Anyone ever done this work themselves?

Is ther any exact mesurements to be aware of?

Anything I should be aware of other than the potential of having to buy a new neck?


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"Question about your nuts"

Now that's a little personal.

"You're gonna love my nuts."

Captain

Trust me mate, this is a rabbit hole you dont want to go down. I've spent the last 18months researching compensated nuts. Designed and made my own, tried manufactured ones.
You will never get completely accurate low fret intonation, whatever you add one place you have to take off somewhere else. When/if I ever crack the code, I'll make and sell em.

On height adjustments of a LSR, be very carefull with that file. You have to keep the underside of the nut as near perfectly flat as possible to ensure it doesnt rock in the slot. It's very unlikely that your bass string slots need to lower as much as the treble strings. Then bare in mind one pass too many with the file can ruin all your hard work and leave you with a unusable nut.

Also you may want to go buy a cheap set of feeler gauges and cut the blades down for shims. Then should anything go wrong atleast you have a accurately sized set of shims.

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No no and no

thanks....

Yeah maybe i'll just take the blue pill. It was only sharp by 1 LED light on a Boss tuner but spot on as far as 12th fret intonation goes so probably best not to push my luck.


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12th fret intonation has next to nothing to do with low fret intonation. Adjusting your saddle wont affect anything below the 6-8th fret much. Its all on nut slot height and nut position (forwards or backwards along the headstock) after the slot is cut.

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No no and no

All nut/fret placement systems are a compromise at best. Theoretically you could fret a guitar perfectly for one gauge of strings, and one person, provided that person was super consistent with their fretting hand pressure, and perfect placement of the fingers every time (which isn't possible with some chords.

As we can't be absolutely perfect, we need to decide how close is close enough.

I would say Niki is right on the money. you could drive yourself crazy trying to fix this issue. in order to get perfect intonation at every fret on every string you would need to refret it with perfectly measured frets that look like these:


Unless you understand these:






it might be a pretty overwhelming experience.

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I'm not an expert, but I play one on the internet.

What effect would lowering the nut slot do, sharpen or flatten the note? On my guitar the note at the first fret is sharp on the G string but I attribute that to the small groove that is on the fret under the G string.

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Tune Low, Play Hard & Floor it!

Hi captianc: I've done plenty of this kind of work myself and I am very doubtful about what you say. The shims are there to set the nut at the right height in relation to the first fret. Unless it was set badly wrong to begin with removing the shims will introduce much worse problems than a slightly sharp note at low positions.

As they pass through the nut slots/bearings the underside of the strings should be 0.020" above the height of the top surface of the first fret. That is a pretty fine tollerance and there is not much room for adjustment in it. Check that measurement before doing anything else.

I won't explain how to measure that height unless you want it, because it is quite wordy. Happy to if needed, though. As suggested above, you are going to need a set of feeler gauges (very cheap tool) and a steel ruler...

I wouldn't dream of removing any timber from around that nut unless there was a very good reason indeed. You've already taken out the shims - why remove wood as well?

Good luck - C

Hi VB: sometimes a nut is cut far too high. In that case pressing the string down to meet the top of the fret bends it enough to make it sound sharp. The effect is most noticeable on the lowest fret positions.

Perhaps captainc has that problem - though I'm worried about the solution he's suggesting, as mentioned in my previous post...

There's a simple visual check to be done to determine whether nut slots are cut too high or not.

Cheers - C

As Ceri said if your slot is too high, you will have a sharp couple of first frets. You only ever lower to a hairs width above the height of the first fret.

Backwards/forwards placement of the strings break point is what really governs your intonation at that end of the neck. It has to be set on a individual string to string basis resulting in a misshapen leading edge of the nut. This is best acheived by creating a shelf rather than removing wood. I suppose you could do it by welding pieces of metal to a LSR, but you'd ultimately defeat the purpose of the rollers.

Here's my measurments for the offsets after the initial measurements were taken.


Here's what it ended up being when it was carved, fitted and slotted.



As you can see they are very differently shaped. The only real way to compensate a nut is to shape it, fitted to the guitar its intended for.

A whole load of mucking about for something you may well not appreciate too much.

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No no and no

Not being an expert Luthier or claiming to be one at all for that matter i can only concur that because the height was to high, it was requiring increased pressure to fret the note at the first fret. About 5 LEDs too sharp on the Tuner to put an image with the thought. Once i removed the shim, i got a one LED sharp result. I got no addition of fret buzz so i'll consider it luck i guess.

I'm reading about 2/64 from the top of the first fret to the bottom of the strings.

Maybe i should just leave well enough alone. I'm happy with the way it sounds and plays, its a frankenstrat, and when the money starts flowing in like leaves on an autumn breeze, Mrs. CaptainC wants to buy me a really nice strat anyway.

Is that with the 3rd fret of that string fretted?

You need to be aiming for around .009" clearance between the underside of the high E to the top of the fret when the 3rd fret is fretted. Your generaly ok up to .012" which is around fender factory spec.
On the bass side you need to be aiming for .018-.020" on the low E. It's lower tension means it vibrates in a wider arc.

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No no and no

Ahhh.

No, I took that with a 64ths ruler from the top of the 1st fret to the bottom of the low E string. My guitar is at work now so will have to re visit tomorrow. Thank you VERY much for your input and advice. And that extends to all tje members here that offered their wisdom. I'll let you know what I find.


Set the gearshift for the high gear of you soul