Stress on tuning head

Construction and repair of Classical Guitar and related instruments
Kevin L Benbow
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Stress on tuning head

Post by Kevin L Benbow » Sun Sep 09, 2012 11:33 pm

Hi all:

I'm playing an Admira Virtuoso that is about 10 -12 years old.

When I changed my strings yesterday I decided I would try a set of D'adario EXPs. I found out that the extra thickness on the basses caused some unwanted buzzing on my fifth string at the second thru seventh fret and on the 4th string from the 7th through 12th fret when playing forte.

Upon inspection I discovered that because my action is relatively low (3 mm on the 6th string, 12th position) these strings were simply striking the adjacent fret, and hence the buzz.

So, I took them off and replaced them with a new set of my normal D'adario pro arte EJ-45 normal tensions. I had no problems with buzzing after that.

However, I noticed that now when proper tension is applied to my 5th string there is a horrible slipping sound from the machine head. :shock:

I should mention that because I change my strings about every 4 weeks (I play about 15 hours per week) I bought a string winder. I have used it now three times.

So, I have two questions:

1. How do I remedy the horrid noise in my 5th machine head? (and, is it about to fail on me? :chaud: )

2. Though I am careful with the winder, is it advisable to use them on CGs?

Kevin L. Benbow
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Marcus Dominelli
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Re: Stress on tuning head

Post by Marcus Dominelli » Mon Sep 10, 2012 12:02 am

As for the machine tuners, it could be any number of things. First, tighten all loose screws (both the wood screws holding the plate to the headstock, and the machine screws holding the cog tight to the rollers). Second, lubricate the gears and the tuner shafts with a couple of drops of oil. Wipe up any excess with a cloth.
If it's still making noise and binding, you may need to lubricate the rollers where they slide in against the wood. Take the tuners out, use a wax crayon against the wood. Don't get any where the string winds onto the roller. If you're still getting binding, the string is probably sticking in the nut. Actually, you should check this first. If this is the case, the nut slot causing problems needs to be re-cut to allow free movment of the string.

Those tuner things work fine on classicals.
Good luck.

Dominelli Guitars

Kevin L Benbow
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Re: Stress on tuning head

Post by Kevin L Benbow » Mon Sep 10, 2012 2:38 am

Marcus, the nut slot makes sense. For my D (4th) string, the slot is slightly angled and I can hear a very mild crackle from time to time.

How do you suggest I check the nut?

BTW, the gutars on your site are beautiful.

klb
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robin loops
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Re: Stress on tuning head

Post by robin loops » Mon Sep 10, 2012 4:20 am

If indeed it is caused by a loose tuning head part and it won't tighten you can try a rubber band around the faulty one and the adjacent one
One Ring to rule them all, One Ring to find them, One Ring to bring them all, and in the darkness bind them.
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James Lister
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Re: Stress on tuning head

Post by James Lister » Mon Sep 10, 2012 9:48 am

Kevin L Benbow wrote:How do you suggest I check the nut?
You could try lubricating the slots in the nut with some graphite (pencil lead). If lubricating the rollers (as Marcus suggests) and the nut doesn't help, you might want to consider replacing the tuners. Most guitars in that price range (and quite a few at much higher prices) are fitted with VERY cheap tuners.

James
James Lister, luthier, Sheffield UK

Kevin L Benbow
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Re: Stress on tuning head

Post by Kevin L Benbow » Mon Sep 10, 2012 3:38 pm

I think it is indeed the nut. Last night I put a very, very small drop of machine oil on the nut and the problem vanished.

It was back a little later though.

klb
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Waddy Thomson
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Re: Stress on tuning head

Post by Waddy Thomson » Mon Sep 10, 2012 5:30 pm

Now you need to loosen the strings and clean the nut with Naphtha, to get the oil off. You don't want machine oil on your fretboard. If you want to lubricate the nut, use the suggested - graphite or a dry lubricant. Oils like Mineral oil might not be harmful, but machine oil is not a good thing on wood.
Waddy

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Kevin L Benbow
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Re: Stress on tuning head

Post by Kevin L Benbow » Mon Sep 10, 2012 6:34 pm

Thanks Waddy. I'll get right on it.
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amezcua
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Re: Stress on tuning head

Post by amezcua » Thu Oct 12, 2017 12:11 am

Is it possible to add a question here after a 5 year gap ? I wanted to know if the inner part of the tuner shaft needs the central wooden part as a support against string tension . The tuners fitted have roller shafts with narrower spacing than many tuners . 33mm instead of 35mm .The original holes look like 35mm spacing . I suppose a few pieces of nylon strip closing the gaps on the top and bottom E strings would support and smooth out any contact . I rubbed a little candle grease on the ends before reassembling. Most of the fixing screws needed at least half a turn to get them snug .

OldPotter
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Re: Stress on tuning head

Post by OldPotter » Thu Oct 12, 2017 8:38 am

I wanted to know if the inner part of the tuner shaft needs the central wooden part as a support against string tension .
Yes, most plates that the rollers are mounted on are not strong enough to support the strings on their own. Too much twisting of the plates will lead to excessive wear and probably make the tuners hard to turn.
The tuners fitted have roller shafts with narrower spacing than many tuners . 33mm instead of 35mm
This would be a bit unusual, perhaps check the distance with calipers. Measure between the centre of the screws holding the crown wheels. I'm not sure why you don't want to fit the correctly spaced tuners.

If you like the idea of improving the bearing surface in the central part of the head, look at rollers incorporating a Teflon or ball bearing??
"When I was younger, I could remember almost everything, whether it happened or not." Mark Twain

amezcua
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Re: Stress on tuning head

Post by amezcua » Thu Oct 12, 2017 5:07 pm

This is a guitar from the 50s that I have just bought. The tuners are not the original ones .You can see different outline traces in the varnish . They needed a good clean and all looked a bit loose on the treble side . Thanks for the reply . I had not considered the support aspect before .The screws are very tiny for such an important job. I wonder if factories have thought about that .

Alan Carruth
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Re: Stress on tuning head

Post by Alan Carruth » Thu Oct 12, 2017 8:09 pm

The screws holding the tuners in actually don't take much stress; a lot of it is carried by the bearing of the roller on the wood. You want the roller to fit pretty nicely into the hole, not too tight, but certainly not loose either.

If the strings are creaking in the nut slots it helps to polish them. Plastic nuts, which you get on many production guitars, tend to dent from the pressure of the strings, and can take an imprint of the winding. The string then tends to skip as it moves, the length of one winding at a time. Bone is less prone to that.

You can use a number of mild abrasives to polish the slots, traditionally it's rottenstone and water. Rottenstone is a fine, soft grey powder that is left behind when limestone breaks down in the acid of rain or groundwater. To polish the slot you dip a piece of cotton string or twine into water, and use the wet string to pick up some rottenstone. Saw it back and forth in the slot for a while, and clean the residue up with more water. This won't remove much material, but it can leave a mirror shine that will allow the strings to move more freely.

I learned about this when I studied lute making. With the extreme back angle of the head they can't stand to have too much friction in the slots, so they make them very shallow (so as not to pinch the strings) and polish well.

amezcua
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Re: Stress on tuning head

Post by amezcua » Fri Oct 13, 2017 3:11 pm

Oh you moved onto nuts Alan. Going back to the mismatch of shaft spacing and hole positions I first noticed the treble side plate was lifting on the e string end. All the screws holding the plates on both sides needed at least a half turn before they were secure .What I think happened over the years was the e string leverage was pulling the roller down without the centre wood supporting the inner end .That worked on the fixing screw and started lifting it outwards.
Have you seen the blueprint diagrams for tuners? They give all sorts of measurements with arrows in inches and millimetres but often fail to write in the roller spacing. But in articles about tuners the roller spacing is one of the first things they mention . There is a newish looking model which fits on either side .There is no difference for left and right. So on one side the rollers tend to press the gears together (traditional design with peg above the gear ) . But on the other side the rollers will be pushing the gears apart .(Peg below the gear . It will start to look like a violin with asymetrical peg positions .
Now I need to take them out for a proper measure to see if any woodwork was done to get the non originals in there . I magnified a photo of a Velasquez guitar head to see the gaps between shafts and holes . 2 out of 3 were spot on with no gap at all on the lower side .The e string was probably a good fit internally though .

Alan Carruth
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Re: Stress on tuning head

Post by Alan Carruth » Fri Oct 13, 2017 5:54 pm

Geared tuners should always be installed with the gear pressing into the worm. If you do it the other way they wear quickly. That's a design fault on the old Gibson F-5 mandolins. You can get one that was 'optimized' by Loyd Loar for, oh, $75,000 or so, and it will be unplayable because the tuners don't work. If you replace them you ruin the 'vintage' value.

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Kent
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Re: Stress on tuning head

Post by Kent » Fri Oct 13, 2017 6:01 pm

Alan Carruth wrote:
Fri Oct 13, 2017 5:54 pm
Geared tuners should always be installed with the gear pressing into the worm. If you do it the other way they wear quickly. That's a design fault on the old Gibson F-5 mandolins. You can get one that was 'optimized' by Loyd Loar for, oh, $75,000 or so, and it will be unplayable because the tuners don't work. If you replace them you ruin the 'vintage' value.
Alan is correct. It is a shame that most F-5 mandolin makers still use the traditional worm under design, when better working worm over designs can be made.

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