Official Luthiers Forum!

o.k so here's one:
living in Israel, we use the metric systems(1cm,2mm).
i sort of got the hang of the fractioanl inches thing too(1/8",2/16").
but when calculating fret distance over at the stew-mac site,i get results in "metric inches"(3.14")? dont know how to properly call it.
so how should i properly refer to it and where can a get a ruler marked that way?

thanks,
Udi.

Good question - most luthier and tool suppliers sell rules that measure to 1/64", but not hundredths.

Places like McMaster-Carr (mcmaster.com), who are more oriented to machinists, do carry rules that are marked in .01s", at basically the same price as rules marked to 1/64s".

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Jim Kirby
kirby@udel.edu

Udi, I don't think there is such a thing as Metric Inches. That mixes the two measuring systems. That 3.14" just indicates inches to the hundreth of an inch placeholder.

Many of us have digital or dial calipers. I use a regular English rule to measure the 3 inches off, then grab the caliper tool to get the .14"

Or something within the length of the caliper, as this is for a 6" capacity caliper, we just set it at 3.14" and mark it or measure it.

I never heard of Metric Inches.

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http://www.dickeyguitars.com

Udi,

Just multiply your "metric inch" number by 25.4 and you will have mm (spreadsheets can be wonderful things) . Then round to the nearest decimal place that your ruler (or eye/hand) can deal with.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Just go here and print out the chart.  I have one hanging on the wall in my shop, and refer to it often.

Inch to Metric Conversion Chart

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

the industrial supply houses, e.g., mcmaster carr, msc, graingers, enco etc., carry rules that graduated in metric as well as decimal(that is the term you were looking for) inches. of those i listed enco is probably the cheapest.

unless you super eyes, have a magnifier handy to work in 0.01".

the rules also often come up at good prices on ebay. for some reason ther are a lot of ebay vendors of starrett tools.

guys, thanks for all the advices, but perhaps i didnt make myself too clear.
i'm in the market for a new ruler.
my old one was rather desroyed when a friend used it to seperate a mirror glued on to a closet with silicone .
no need to worry, i broke both his hands so he will not be doing that again anytime soon
so i figured if i'm going to get myself a new one, and i will be ordering it from abroad(couldnt find a long enough,quality ruler locally), i might as well just get one that is most useful to me...instead of going and multiplying things by 2.54 or using charts for conversion.

now Bruce(how are you doin'?), i know there aint such a thing as "metric inches", just didnt know what to call it. its much easier over here, you just go to the store and say "good morning, i need a ruler".
just one measuring system around here.

and J.Kirby,
thanks, i'll look into mcmaster-carr.

dismissed.
Udi.

I work in both .. frets are always done in mm in my shop though (as my spreadsheet prints out in mm), unless I am using the SM templates, and then you just cut the slots, who cares what you call the measure. i do however, always refer to the scale in inches ... I know, wierd. But its handy to know both and be able to transfer back and forth.

Lee Valley has a great set of stainless rulers, 6/12/18/24 inches long, that have both meteric and imperial on them - super stuff, and cheap to boot - I have two sets, one in each shop room.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Hi Udi, like Michael said earlier, what you call these 3.14" stuff is decimal inches

Remind me, if we ever meet to not use your ruler to remove a mirror I like my hands the way they are.

I measure most everything in inches (although Canada is suppose to be on the metric system) but for the placement of the bridge, I measure that out in mm, just easier for me.

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My Facebook Guitar Page

"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

Well, I live in the US of A, and I'm supposed to like and use inches, either decimal or fractions, but, I like and use millimeters.  It is easier to see, easier to read, and fairly easy to convert inches to mm in your head, once you get used to doing it.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Here's a program that we use at work to do some quick conversions.

you can download it free on the internet at this link:
Convert

Enjoy!

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Thanks,
Blain

http://www.ullrichguitar.com

"89.67% of all statistics are made up on the spot."

http://www.onlineconversion.com/length_common.htm

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Freeborn Guitars
and home of BeauGuard©

Kilogram's always mass, weight's measured in Newtons. Any other usage is (technically) incorrect, but scales basically do the conversion for you, letting you weight something (in air, at sea level) to get its mass.

I do everything in inches, because I believe it's a better system. With metric, using tenths of a mm as the smallest unit doesn't seem small enough, but hundredths of a mm seems a little silly. I like thousandths of an inch. Just right.

Regarding the decimal equivalents of fractions, they are really pretty easy to just memorize because there's a pattern to them. Try it, you'll like it.

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John Watkins
CNC Guitar Parts

To me, metrics refers to the units. Metric unit: cm, our unit: inch. Both can be expressed with either decimals or fractions: 3 1/4 cm or 3.25 cm,   3 1/4 inches or 3.25 inches.

Ron

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OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

I'm 99% sure that you're looking for an SAE ruler.
SAE stands for "Society of Mechanicl Engineers."
If you google SAE you'll find alot of papers wirtten on fuel injectors and how to measure gas emissions and junk like that.
BUT further looking will reveal verniers, calipers and other measuring devices expressed in metric and SAE.
So i guess thats a standard.
Conversions are expressed as: 01mm or 0.0005"

I asked this question to an engineer friend who told me it was called SAE.

I'm sut a lay person but that sounds like the right track.

Don't know where you'd get such a ruler from, however.
Engineerig school, perhaps?

I hope that helps.

Cheers,
Claire

Where's the Edit button...*laugh*
SAE = "Society of Automotive engineers"

Claire

WOW! this has grown much bigger than i expected it to.
any ways, thanks all!
i think i've found what i was looking for over at mcmaster-carr.

you've all been very helpful + ive learned a new term - "deciaml inches".

very productive indeed!

1.00" = 25.4000mm That simple

3/8" x 25.4 = 9.5250mm
.375 x 25.4 = 9.5250mm


2" x 25.4 = 508mm

508mm/25.4 =20"

25.4 is the ratio of mm to inches

Humm dropped a Zero

20" x 25.4 = 508mm

508mm/25.4 =20"

I picked up a nice 6 inch rule at my local hardware store and I've never found another one like it. It is made by General and has four scales: 1/32" 1/64" 100ths" inch and .5 mm. For most lutherie I don't use the 1/64" all that much but the other three get used all the time.

As for why scale lengths are in decimal inches, it is because the American guitar companies were in the US and used inches. And, measuring out fret distances using fractions is awful. Almost every dimension on a guitar is somewhat arbitrary so it is easy to chose a value that is a reasonable fraction. The major exception to this is the fret positions. Those have to be places based on the 12th root of 2 and will never land on a nice fraction of an inch. To use fractional inches you would have to convert the value in decimal inches into the nearest fraction which would be in 1/128th" half the time. Yuck!

I have had many Europeans, Canadians and other non-American machinist and even some engineers try to convince me that the metric system is inherently more accurate simply because it is a base ten system. While this fact may make memorization of units divisions simple, it does not make it any more or less accurate.

In fact it really does not matter what unit of measure you use. One is just as accurate as the next. The only thing that determines accuracy is the the number of divisions of the base unit of measure you are willing to measure to.

A machinist can be just as accurate with one unit as any other be cause all units can be carried out to 10th, 100th, 1000ths and so on and so on

Let say I invent a new unit of measure called "KRUTONS". and let say 1 Krutons is equal to 1.9787 inches. Now for some reason I need to know the inch equivalency of 36.953 Krutons in inches to the nearest thousandths of an inch.

36.953 x 1.9787= 73.118901 (exact inch decimal equivalent)

and expressed in the nearest thousandths of an inch would be 73.119

Some will say "see the inch equivalent is not as accurate and the Kruton because the the actual inch equivalency can not be expressed in 3 decimal places."

That is not an accuracy issue, rather a mater required or appointed tolerance (a point in which the difference in further unit division is inconsequential to the task at hand.)

Famously, the Massachusetts Avenue Bridge over the Charles River between Boston and Cambridge is 365 Smoots and one ear long. The Smoot refers to the height of a pledge in one of the MIT frats who, it is said, was laid end to end while intoxicated for the original measurment. The frat now has a 'standard Smoot' bar, and the pledges resurvey and mark the bridge once a year. Joggers, I'm told, find the markers quite reassuring in a fog.

I like to work in "Skoshes"

So tell us, Robbie, how do you convert between skoshes (from the Japanese sukoshi or skoshi), metric and English?

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