"Rogue" String -- or what?

[JayVeeGee]

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I don't even know if that's a possibility ~ a 'rogue' string causing a raised string to return sharp?

My low B string (10) is returning sharp after raising it with the A pedal. It only has that single raise on it with nothing else passing through the changer finger that could be binding. I've tightened the tension on the return spring that's attached to the lowering finger but it still returns sharp.
The new changer has just been recently installed after new lubrication so nothing there should be binding/sticking.
All other raises and lowers return to pitch without issue.

I have read the suggestion that the angle of run of the string as it comes off the nut roller to the machine head could have an adverse effect. That 10th string does come off at a bit of an angle and if that's the cause then I'm a bit stuck without performing some fairly major surgery.

Any suggestions will be welcome.

[JohnDavisStringsHere]

Jim, if your not to far from Ron Bennett get him to have a look, i dont think its the string but i could send you a couple of 38's if it helps?

[Mcneilwaeasteel]

Jim
Here comes some theory from a Numbtie if a string is stretched between two fixed points and returned to the same fixed points, it should have the exact same tension on it
B U T ———
If the roller at the headstock is slightly oval, ( like a rugby ball for instance ), when it moves with the string it could return to a slightly different position and that could be stretching the string enough to make it sound slightly sharp.
I know your method of making the rollers is limited and they cannot be completely accurate, as they are “ hand turned” on an electric drill or filed, it’s a long shot but it could possibly be an answer to your problem.
As I mentioned in my opening statement.
THIS is only some theory from aNUMBTIE but it may be the answer to your problem, so try another roller and measure it with a micrometer if you can, then check the old one to see if there is any discrepancy between them, OR
if it cures the problem just sit on your and play the beast!
I hope this helps, as it’s the best I can come up with this early in the morning!
Cheers
Robert

[JayVeeGee]

John ~ thanks for your very kind offer . . . I'll hold off for now as I try a couple of things.

Robert ~ Thanks for your suggestion. I've backed off the 10th string enough to slip it past the nut roller and had a good look at the roller. It moves freely and I can't see anything wrong there. Popped the string back on and pulled it up to pitch. With that 10th string there isn't much movement in it at the changer end when the pedal is pressed (and that's a whole tone raise) and there is no perceptible movement of the string or roller at all at the nut when the pedal is pressed and released repeatedly.
As you mentioned, my rollers are hand made and my main concern at first was that there may have been some string buzz especially with the bar at the lower frets, but the first thing I did before even trying to play a note was to check all strings with the bar down at the lower frets, right down to fret 1 and no buzz was detected.

In my earlier post I said the string comes off the roller towards the machine head at a bit of an angle -- now I'm not sure where I was when I thought I saw that! . .
. It comes off pretty much perfectly straight. (It's only the 9th string that has a bit of an angle and that's because of the way it has been wound on to the peg)

[Mcneilwaeasteel]

Jim
Could you try placing a bit of angle over the roller, or add a bit of metal in front of it to raise the string up and give you a fixed nut?
Then try using the pedal to raise the string and see if it returns to the same pitch, if it does return ok, it’s the roller end that’s causing the problem, if it’s still going out of pitch it’s the changer end.
Could it then be something to do with the string ball end moving or jamming in the finger if you’ve eliminated any other movement somewhere else in the mechanism?
I hope this helps you in some way, as this Numbtie has run out of ideas and my brain has now went numb!
Cheers
Robert

[Tony Russell Davis]

I'm assuming the guitar is an all-pull and that, when you re-fitted the changer after stripping down, you put all the rods through the same changer holes as before? Or was it a completely new unit?
'Drag' at the nut generally causes a raise to return flat, because the string gets pulled over the roller but can't return all the way back - so there's more slack left in the string than before.
A raise returning sharp is usually because the pull rod doesn't have enough travel, i.e. not enough clearance at the tuning nut. When you tune the open string and then engage the pedal, do you have to retune the raise? And having done that, when you let the pedal off, do you have to retune the open string? If so you need to back off the 'hard stop' a tad to give the rod a little more travel. The 'hard stop' is generally at the pedal crank.

[JayVeeGee]

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('Heavy duty' child minding has kept me away from the forum and the steel for a couple of days! . . . but I'm 'off-duty' for a few days now. How has my life got so much busier since retirement???)

Robert ~ You mentioned the ball end of the string being properly fitted into the changer finger. I had noticed it was possibly not seated properly so I tweaked it into position then tensioned the string. That seemed to help a little . . . or maybe I just imagined that? but now it's over to > > >

> > > Tony.

Tony, I hang my head in shame a little as I should have known to have backed off the nylon adjuster at the changer. I had been aware that it was tight against the raise finger but that other half of my brain didn't click in!
I've backed off and locked the pedal stop so that the floor pedal now has a little longer throw but that has allowed me to adjust the nylon tuners on both 10th and 5th strings - - - and they're now both sounding right.

THANK YOU for pointing out to me what I should have realised.

Now all I need is someone to come along and show me how to play this thing. (How many years have I been saying that???)

[Tony Russell Davis]

Great to hear that Jim - "my work is done"

[JayVeeGee]

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Yeah, Tony ~ great work! Thanks again!