Official Luthiers Forum!

Ok I am not really trying to stir up trouble but I have to try to understand this.

Our friends from overseas use the metric system but us in the US don’t. There was a big push in the 70s to try to convert but we still use inches/feet/yard etc for the most part.

I understand the advantage of the metric system, but if you work in thousands of an inch you get the same advantage. All my machines in the shop are based on the inches and about the only time I deal with metric stuff is for hardware (Gotoh tuners for example use a 10mm hole) … I just don’t think metric.

When our friends from overseas post something and refer to a dimension in mm, I understand. I will take the time to do a conversion to inches for my use.

Now my problem. Why do folks from the USA post on forum their dimensional stuff in mm? Are they being nice to our overseas friends? To me they just sound pretentious, kinda like the people who will put on a fake accent to sound smarter. I am missing something here? Should I really be learning the metric system for use in lutherie?
johno38696.3224074074

I use both. It is hard to measure with a ruler in thousandths. It is easier to measure with the metric system. I have a caliper for measuring tops and side thickness that is also metric. And of course it makes me look cooler than I am.    

[QUOTE=johno]Should I really be learning the metric system for use in lutherie?
[/QUOTE]

I think both systems have advantages, the metric system is decimal, meaning it's much easier to do odd divisions/multiplications, and adding and substracting is straightforward. Learning the imperial system drove me crazy (how many inches in a foot, how many feet in a yard, what's 1'11/16 minus 13/32 and so on) but it becomes handy when doing fractions, or even doing super-tiny and precise measuring (like 64th etc.). I use both all the time, I know carpenters who use metric when calculating stairs for example, much faster than the imperial system which really plays with my sanity in those cases…

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

[QUOTE=Tom Dowey] It is hard to measure with a ruler in thousandths.[/QUOTE]

I have a great little 6" scale and a 24" scale that is graduatd in 1/10s of inches and 1/100 of inches. Use em all the time! Of course my dial calipers measure in 1/1000s.

[QUOTE=Tom Dowey] And of course it makes me look cooler than I am. [/QUOTE]

Remember it is not how you feel ... it is how you look ... and you look marvelous

[QUOTE=highdrawlicks] (pretentious egalitarian artifice) was born in the New World. Might not some of them be European exptatiates
[/QUOTE]

See what I mean? I have no idea what he is talking about ... You must be talking metric ... Just having fun

[QUOTE=laurent]
the metric system is decimal, meaning it's much easier to do odd divisions/multiplications, and adding and substracting is straightforward.[/QUOTE]

Yes I agree but ... if you use thousands of an inch than you have that advantage too AND everything is compatable with the scales on my tools in my shop ... table saw, milling machine, lathe sander jointer etc.

I don't use the metric system too much because I have no idea what a mm or cm is since I don't have a scale but I do use decimals of an inch which I do understand. It does seem rather odd though that we started dividing inches by the fractional the parts that we normaly do, 8ths, 16ths, etc,   must be something to do with the Brits huh?

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Tickle your guitar daily, and it'll tickle you back.

I use metric because I build classicals, and just about every measurement in classical building is given in mm due to historical considerations. Scale length, table thickness, etc. My dial caliper is in mm, and so are my rulers. It's just how I work, so all the thousandths stuff flys over my head. I have no feel for what, say .009 actually is, in terms of thickness. To figure that out, i have to either multiply it out to get mm, or try to figure out what fraction that corresponds to.

There's nothing pretensious about it, it's just how most classicals (certainly not all) are built and measured. Imagine how frustrating it would be to try to work on a European car with American tools. Endless conversions, math, fiddling.

I use fractions too but switch to decimals at fractions smaller than 1/64. I get muddled when I try to think of fractions like 1/128, 1/256, 1/512. Plus, I can't seem to get my digital caliper to give out fractions.

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now known around here as Pat Foster
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http://www.patfosterguitars.com

I would like all measurements in forum to be in metric. I is easier and totally logical. From a Metric American.

As a European early educated in Inches and now a professional scientist teaching and working in metric I know which I prefer and is most logical. And I don't think that US luthiers posting in mm is pretentious just being more rigorous in terms of international acceptance (using standard SI units). And since when was this a US forum, I thought it was just an open luthier forum, or do you consider non-US luthiers to be interlopers?

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

[QUOTE=John How]It does seem rather odd though that we started dividing inches by the fractional the parts that we normaly do, 8ths, 16ths, etc,   must be something to do with the Brits huh?[/QUOTE]

Probably has to do with half of a 1/2" is a 1/4" and half of 1/4" is 1/8" so on ...

I suppose if you did that to centimeters ... made them fractional you would have simular problems. 1/2 of a cemtimeter is what, 5 millimeters? What do you guys do when you want to breakdown a millimeter. What is half a millimeter? 500 micrometers?

So if you are working in thousands of an inches (milli-inch) there really isn't any difference in handling the math except a milli-inch is about 40 times smaller than a millimeter.

Colin please take this as the joke it is meant to be

[QUOTE=Colin S] As a European early educated in Inches and now a professional scientist teaching ... Colin [/QUOTE]

See what I mean about pretentious!

[QUOTE=Colin S]
I thought it was just an open luthier forum, or do you consider non-US luthiers to be interlopers?[/QUOTE]

Not at all of course everbody is welcome but I don't think we should post in french just because some of friends here are from France or Canada.

I don't use metric either. Guess in part that I grew up using inches and I like thous. on my calipers. Stewmac had a thickness measuring caliper tool ( for measuring archtops and mando tops) and it was in Metric. They got enough requests to change it to inches/thousandths. My eyes tend to measure in 1/2", 1/4" and so on. Just can't get this brain to work in the cm/mm mode.

Side - HEY JOHN how are? haven't seen you around these parts in a while. Glad to see your input/back.

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Dave Bland

remember...

"If it doesn't play in tune...it's just pretty wood"

[QUOTE=johno]
What do you guys do when you want to breakdown a millimeter. What is half a millimeter? 500 micrometers?
[/QUOTE]

0,5 mm.

We use only the metric system in this country, I think we became "officially metric" in 1873. Obviously both systems work, you just need to learn it by heart early on and it becomes second nature. I don't have an opinion as to which system is more logical as I only learned the metric system and my opinion no doubt would be colored by this (I think most of the posts in this thread are evidence of that). However, we all have to deal with the very real problems of diffent standards for dimensions for machinery and such. The world oustside of north America and to some degree Britain and parts of her old empire is metric. I think you should join the rest of us, it works just fine, you'll see!

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Rian Gitar og Mandolin

I was at David Berkowitz and Linda Manzer's baritone guitar class at ASIA this year. Linda Manzer was just as bad, it was a riot!

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Rian Gitar og Mandolin

I think one of the hurdles I face is trying to convert metric to Imperial measurements. For example: rather than excepting that something is 6 cm, I have to convert it to inches, dividing by 2.54 and figuring it out to be 2.362 inches. But when I look at inches, it's just inches. I think what you grew up with is pretty much what you use unless you are some sort of science geek. (ducking for cover now. )

A while ago I sent a six inch scale to a luthier in Spain who said he was
raised on metric but preferred the "greater accuracy of the inch-based
system." It took me a while to figure that one out, and I finally decided
that it was a matter of orders of magnitude.

Working with thousandths of a inch is a decimal system, and easy to
manage, and the units are a convenient size for accurate work - not that
I'm prejudiced, mind you. The units below a millimeter get to be a bit
less easy for me to understand. Tenths of millimeters are a big (.004"
each), and hundredths are really tiny - only 40% the size of a thousandth.

As to the conversion to metric - I really wish that had happened. I'd have
learned to use the system that, in spite of my foregoing rationalization,
makes more sense overall. I recall reading in "My Weekly Reader" more
than 50 years ago that we'd be using the metric system long before now.

Of course, we'd also be driving cars in tubular skyways, and be living with
World Peace by now, too. . .

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Cheers,

Frank Ford

FRETS.COM
HomeShopTech
FRETS.NET

I was lucky, at school I'd just learnt Imperial measurements the year before we adopted the metric system which I then had to learn. So now I use either, any job I do is usually half metric half inches - which ever side of my rule is facing up. The exception is when I need to start dividing, I'd much rather do this in decimals.

When I post here I try to keep it in inches simply because most members are in the US and don't use the metric system.

I find mm are plenty accurate to measure pretty much any part of a guitar (it's made of wood, it'll move anyway), and it's easier for me to think in mm. This said, due to the overwhelming majority of steelstring builders being American, I'm fairly conversant in larger dimensions in inches (ie, lower bout width, overall length, etc.) but it makes more sense to me to measure the smaller stuff in mm. Anything much smaller than 1/4 of a mm requires major magnification to actually mark onto anything. Fractional inches are especially annoying when I have to start thinking about adding them, etc. And decimal inches are frankly relegated to machining, and I've yet to meet Americans without a machining/lutherie background who think in decimal inches.

There's also tradition mixing things up: classical builders tend to refer to dimensions in mm (Spanish tradition), steel string builders tend to use inches.

Honestly, as long as you know what you're measuring, it really doesn't matter. But for general ease of use, international standards compliance (some NASA projects have gone haywire due to metric/imperial snafus), metric is more logical choice, and can be just as accurate.

I do both, have to, being a Brit of a certain age (40shhh.. ) I was brought up inch's ect, but use mm for smaller messurement as they knock down easier, my mind just won't do 52/64th's or what ever but nether will it do "yes it's 15 km away", I mean what that! miles man give me miles! I still think in inch's, feet, miles ect I still drink a pint and still buy my apples by the pound, although their proberly french grrr now there's something to hate.

It sounds like many people use both. At SCGC we used both, depending on the process or part. No specific reason that I could tell, but we had some things in fractions, some in decimal equivalant and some metric. When we started using digital calipers it became very easy to move between units. I was once giving a tour to a un-named but well known builder from a country that obviously ONLY used the metric system, and when he asked me about the dimension of a particular part, I answered with a fraction, and he actually became a bit upset and dismissive, as if you could'nt possibly measure anything accuratlly without the metric system.    

    One thousandth of an inch is the same whether measured with standard or metric scales. I use a machinist scale that is cut in .100" or 1/10th on an inch increments alond one edge and .010" or 1/100ths of an nch on eht other. Flip it ove and you have 1/64ths and 1/128ths on each edge.

   If youn have a scale that is cut to 1/64th increments, just conside that a 64th is about .015" or 15 thousandths of aninch an you'll be able to measure with very close estimation down to .005" or so.

   If your really in need of an accurate measurement, though, a scale and your eye aren't enough and you need to get either a veneer or dial caliper to give you true readings that can be taken to .0001" or a tenth of one thosandth of an inch increments. I prefer a vem\neer caliper for my metal machine work, but it is completely unnecessary to use them for wood and I keep a couple of dial calipers on my bench at all times for that work.

   Whatever system you meausre with, it all works out and the same results can be achieved.

Kevin Gallagher/Omega Guitars