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accuracy is accuracy no matter what the method of measurement . As a machinist I had to work to .0002 Nothing on a guitar needs that tight of a tolerance.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Yes...not even close.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

MAAAAAAAANNNNNNN this explains alot !!!! I been using one of my stretchy Suspender Scales to get my Scale Length !!!

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The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

"MAAAAAAAANNNNNNN this explains alot !!!! I been using one of my stretchy Suspender Scales to get my Scale Length !!! "

Do you build those gypsy jazz guitars? (The ones that play those minor suspendered 7th chords.)

No need for a guitar strap when you're wearing those babies!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Dave's digital caliper playing up IMO ...

Nope - 1.000" = 25.400mm

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Steve Smith
"Music is what feelings sound like"

Jim and Clay, you guys crack me up, suspendered 7th chords.....

Ken

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Are you guys talking US mm or Canadian Imperial mm, because Imperial mms are bigger than US mms, just like
US gallon and Imperial gallon. LOL !!!
Brent

I am not sure whether that was an attempt at a joke, or whether you are being serious, but on the off-chance that you are in fact being serious, then that is absolute nonsense.

What differs between the US and Canada is the imperial system ... yes a Canadian gallon is different than an American gallon



A metre, however, (or "meter" in the US) is exactly the same length anywhere in the world . . it is an international standard. It follows therefore that a millimetre is also exactly the same length anywhere in the world.

it is a slight confusion that "mill" is used in the US to describe a thousandth of an inch, whereas "mill" in the UK is an abbreviation of "millimetre".

a meter is 39.37 in long
so 1 divided by 39.37=.0254
so there are 25.4mm per inch

http://www.metric-conversions.org/lengt ... inches.htm

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Is an inch EXACTLY 25.4 mm? No, but up to 14 decimal places, it IS 25.4 and another 13 zeros. At precision (NOT accuracy) beyond 14 decimals, it is a wee bit less, not that a luthier would care, but a microscopist would.


Sent from my iPhone using Tapatalk

A wee bit more, surely ???

Ah, no. There are lots of measurement converters on the net, but I like this one because it allows you to specify the level of precision: http://www.sciencemadesimple.net/conversions.html
Check it out and ask to convert 1 inch to millimetres at 15 or more decimal places.


Sent from my iPhone using Tapatalk

The only folks who may have any vested interest in 15 decimal places would be mathematicians.
Tom

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A person who has never made a mistake has never made anything!!!

Sorry, but much as I would like to let the thread fade away, I have to take issue with Tim's assertion that the inch is slightly less than 25.4mm

From Wikipedia (and I have no reason to doubt their veracity on this occasion)


Now, 914.4mm, divided by 36, comes out exactly to 25.4 . . . no repeating decimals, no matter how many decimal places you care to go to. . just an infinite number of zeros.

How that calculator to which Tim linked is programmed to operate, I have no idea, but one thing for sure, their calculation for the number of millimeters in an inch is erroneous, period.

And just to further clarify the matter . . .

Shades of HHG discussions!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

If one wants to study and work with classical guitars one needs to be able to work in mm.
In our recent book "Inventing the American Guitar" we chose to publish both mm and inch values as internationally this makes sense.
It's always interesting how things long established came to be.
It's said that Roman roads were built to accomodate the back end width of two horses as per a Roman chariot. Perhaps the guitar scale was based on half that distance as the early makers had customers who fit the description. <GRIN>

Nice bit of research and I have to eat humble pie on this one.

Hmm, or do I? This is where the story takes another twist, 'cause it turns out that one inch does NOT exactly equal one inch -- at least not in the US (no doubt where the online converter originates). The US and UK have more than once stubbornly retained traditional measurements within their borders, even as they sign international agreements, such as the one murrmac references that redefined one "standard" inch as 2.54 mm, "exactly". BUT, in the US, legal surveys continue to use the "US Survey" inch -- which is indeed a wee bit shorter -- only in America! (You can find all this on Wikipedia as well).

Personally, having grown up in Canada during the active period of "metrification" and being a scientist, I feel that the inch, and especially fractions thereof like 1/64", make little sense and should have been dumped ages ago. I divide/multiply/think by 10's a whole lot easier. Nevertheless, I do have dial indicators and a few other measurement tools in my shop that are not in metric units (yes, all of them American made), so I continue to use inches for some things. Standard or US Survey? I never measure to a precision better than 0.0005", so it doesn't matter.

In 1985 I was giving some Engineering papers in Canada. I thought I would be smart and do everything in metric primarily, with US in parentheses. Well, the Canadians up there where I visited gave papers in US units, British units, and some in metric, but metric was the least used.

But I drift.

As mentioned earlier, the evidence I've seen and measured over the years shows Martin used fairly simple lengths of 25" and 25.5", but spaced to the rule of 18. When they converted to modern spacing they used 24.84" and 25.34" as close approximation to where the prior lengths ended up with the rule of 18 spacing (allowing them to maintain consistent neck lengths/bridge positions). The only missing link is historical documentation from Martin that these were the base numbers used to calculate spacing. Unfortunately even their earlier catalogs use their peculiar definition of scale length as describing rounded end lengths with compensation (24.9" / 25.4"), rather than listing numbers actually used in spacing of the board.

It's the simplest explanation I've found for their seemingly odd lengths, and pretty well supported by measurements on historical instruments.

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Eschew obfuscation, espouse elucidation.

Richard Brune' has done many measurements on Torres guitars and claims they pretty much come out even expressed in inches.

Evidence of their pre-metric origins or Torres was simply using an English made measuring rule.

An interesting check David would be to take precise measurements of the early Martin guitars which had 22", 23 7/8" and 24.5"
scales (sizes 4, 2 1/2 and 2) these sizes did not make it into the modern era and so perhaps have not been "re-interpreted"?

I have to amend my last post actually, and say that I can only identify their intents behind spacings to as early as the 20's. Before this, the spacings are simply too irregular to easily identify the base numbers and intent behind them. It is only from the 20's through the late 70's that their spacing is reliably identifiable as done to the rule of 18. Before this, either the tooling errors are too great, or the system and base numbers they used could be all together different.

So that's a very good point you bring up. Just as the modern 24.84" / 25.34" appear contrived to match the lengths used in the prior 50 years, that system could well be derived from one even different which was used before then. Irregular spacings (whether by intent or error) can pose quite a challenge to figure the underlying numbers and formulas behind them.

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Eschew obfuscation, espouse elucidation.

There being some who believe that the string length is important for the best response for the chosen tuning of the instrument. Is there any evidence or belief that the changes in the customary scale lengths evolved from changes in preferred tunings, including the change in the definition of standard pitch?