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I have a 1980 Kohno 30 classical that constantly slips out of tune on some keys when I play. Some good repair men have looked at the guitar and they believe that the machines are in good condition and installed properly, hench no change other than lubricate the gears and rollers, which did not help. So, I guess I need to try other machines, but I do not see a source. Best I can tell they are 78 mm from end to end. Is anyone familiar with this guitar so that thye can recommend replacement machines?

Try sending them an email.  Maybe they can tell you what the machines are.  Here msakurai@kohno-guitar.org

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Waddy

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Actually, Kohno did use a larger spacing on many of their guitars and 78mm sounds about right. You could check around at some of the classical guitar retailers, or go with the Gilbert individual machines. Gilberts are not the most beautiful machines, but they work well.

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Hi Bill, Alessi makes machines in various spacings I believe. How are you measuring? Just measured a set of 35mm spacing machines and from the front to back they're right at 79mm (at the gear). Its not a good way to measure. Let us know what the measurement is from the center of one gear or roller to the next. 35mm is standard, 36 wouldn't be uncommon for your guitar though.

Also.. check the nut to make sure the slots aren't too tight or rough, if your guitar is not holding tune well.

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Gilberts are on 35mm spacing.  Good chance they are Gotoh's.  Do they have a screw in the bottom of the knob?  Do you have a picture?  That might tell us a lot.

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Waddy

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Bill,
if indeed 78 is the spacing, you'd might like to check this out:
39 spacing classical machines

there was a german company who used to make tuners with this spacing - i think it was called "kolbe" but i'm not sure if they are still in business.

also, you'd might like shooting Martin Guhl
(martin.guhl@googlemail.com) an e-mail.
he is involved with a german based company who makes tuners, called "Rubner".
he might be able to help.

Udi.

Gilbert 3-on-a-plate are 35mm spacing. You can use the individual machines to work with any spacing.

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Sure you can, but I don't think I'd do that to a Kohno.  It would require drilling a  bunch of new holes in the headstock.  It is a fairly valuable Classical Guitar.  New ones are in the $6K range I believe.  In 1980, a Model 30 was probably somewhere in the $2000 +/- range.  By the way I noticed that the new Kohno's have Van Gent Tuners on them.

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Waddy

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My 1979 Sakurai (supervised by M. Kohno) guitar has the 39mm machines, and has no problem.
I would look elsewhere for the cause of your problem.
Nylon strings are constantly stretching, and need to be retuned frequently until they reach some degree of equilibrium. Changes in humidity can cause the treble strings to shrink and tighten - resulting in higher pitch. I find it necessary to retune my strings every week or so.

Ray

Why not just measure from the top of one roller to the top of the next.  Same as center to center isn't it?  Or from the top of the bottom roller to the top of the top roller for full distance?  I assume you are locking your strings in some way to the rollers to keep them from slipping. If you look on Dave Schramm's website, there is a Gilbert article on how to string a classical that is very good - trouble, but good.

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Waddy

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Good point Todd...  I hadn't allowed for the difficulty of measurement in that manner.

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Waddy

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Sound Clips of most of my guitars

Didn't read it all.  If you pull the tuners you can measure the rollers with a ruler.

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Waddy

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Sound Clips of most of my guitars

I just came across these wide spaced machines on Allparts site. Might be just the ticket?

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Stay with the happy people.
--Reynolds Large

Thanks for all of the comment.   By ene-to-end, I meant all three keys and not two, but I did measure from center of gear screws and other correct locations so that I am not double counting the ends. 78 mm is correct, unless it is some tiny fractional mm also, which I doubt. The guitar recently got a new nut by Yuris Zeltins along with other work. It had the problem before, and still does. It stays in tune in the case, usually, but the A and D go out of tune in a few moments of playing, and go out again and again after I retune and play again. I am careful to finish tuning with a tightening turn, so that if the strings were hung up in the nut, they would go sharp when they slip, but they always go flat. It does this even with old strings. The machines are definitely slipping. All of this is in addition to changes with weather, which is normal.

Does anyone have knowledge of the proper clearances needed, if any, for the rollers? I was wondering if the machines are not developing enough friction becasue maybe the rollers are supported by the wooden holes, and maybe should be clear of support, so that the strings can torque the worm and gear together. Does that make any sense?

I have a question here.  Do you expect your guitar to stay in tune from one day to the next?  I can't imagine that.  I have to tune frequently.  The D and A strings will probably have a little more variation than the E or some of the trebles, because of their limited diameter in wound strings.  It is also the reason the D is usually the first to break.  As a matter of fact, I was reading an article on the Kohno site, and in the FAQ section, they recommend detuning a couple of turns every day when you put your guitar away.  I had never heard that before, but it probably is like taking the pressure off a bandsaw blade, and it makes sense for the health of the guitar.  It does however create a tuning monster, in that newly stretched strings usually don't settle down for an hour of playing or so.  I guess that's where the hour or so of warm up comes in, huh?

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Waddy

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No, I don't expect it to stay in tune from one day to the next, or even for an hour. But I need it to stay in tune until a piece is finished. It is really getting bad.

PS I have other guitars that stay in tune.

Yeah, that is bad.  Although, since a lot of my playing is outside in the fall, I'm used to going out of tune before the end of a piece.  I have guitars that stay in tune too.  Although, I think most of them probably need new strings when they get to that point.

Have you taken the tuners off?  Can you tell if they have metal centers to the plastic sleeves, or are they plastic all the way through.  I have seen some that are, though most good ones have steel or brass bars through the middle.  Also don't forget to send an email to Kohno, address in my first post, they may be able to tell you exactly what tuners are on the guitar.

Here is something else to try.  Take a grease pencil and mark the tip of one of the gear teeth and put a mark on the tuner wall at that spot.  See if it is slipping there.  If not, it is either the strings slipping or the sleeve slipping.  If it is the sleeve, it is either cracked, loose, or stripped - you have probably tried this, but see if you can tighten the screw, or take it out and try putting some kind of filler in the hole, maybe epoxy, also see of it is cracked.  Sometimes you can get replacement sleeves for these tuners.  You can also do the slip test with the sleeve.  put a little piece of tape on the inside of the slot, put a mark on the sleeve and a mark on the tape.  If the screw does not move and the sleeve does, there you go.  Either way, you are probably going to have to take it apart.  I should've thought of all this before.

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Waddy

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Sound Clips of most of my guitars

  Oh yeah, if nothing moves find a new kind of strings.  Some strings notoriously do not stay in tune, and some will not intonate right no matter what you do.

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Waddy

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Sound Clips of most of my guitars

I was using strings brands that I have for many years, and I use them on the other guitars. The tuners have metal centers in the rollers, so I assume if the plastic sleeve kept slipping, they would shear the strings, but I will try the tests you suggested. The D roller is cracked. I did email Sakurai, but it is the weekend, and no reply yet. As far as other posts with sources for 39 mm or 1-17/32 ", I do not think that my eye could tell the difference in these two lengths, and I do not have a vernier caliper. I guess I would need to go to a shop and just try them, if they have these in stock.

1 17/32" is 38.89375mm.  Most places would call that 39mm. 

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Waddy

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Sound Clips of most of my guitars

I believe that Kohno at that time was using Fustero tuning machines, which are available in both 35mm and 39mm spacings. Rubner and other European vendors still supply tuning machines in both spacings although 35mm is now the standard for the majority of tuning machines.

Shawn, are you back?  Look forward to your review of the class.  Hope things went well.

Sorry for the hijack!

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Waddy

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Sound Clips of most of my guitars

The machines look just like the Gotoh that one of the others posted a link to. I got replacement Gotoh rollers from LMII and they fit, but that is not the problem. They were cheap, so I just did it. In the process of disassembling the keys, I noted that the crown gears are visibley worn, and that may be the problem. LMII says that Gotoh does not sell parts, and apparently LMII doesn't know of other substitutes. Does anyone know of a source for replacement crown gears for Gotoh classical?

Another thought...if it is just your A and D that go out of tune, it could be that the strings are pinching at the nut or are rubbing against the headstock. If there is something that is holding the strings as they are being tuned such as a nut slot that is too tight, tuning will result in the right pitch but the section between the roller and the nut may be loose. Then as the guitar is being played the vibration of the strings may be moving the string enough to get it to release some of the slack which is why it may be going out of tune.

Are you using the same strings?...if this same behaviour is happening with different brands of strings then I would look first at the nut and or saddle and in most cases the tuning machines may not be the culprit.

Hi Waddy...yes I am back. Will post info on the Romanillos class separately.