# Converting Millimeters to Fractions



## CharlieM1958 (Nov 7, 2006)

Okay, so it's a slow day at work, but this has been a pet peeve of mine. I often run across a measurement given in millimeters, and wish I had a handy reference to convert that number into fractional inches.

There are a lot of charts and calculators online that will give you decimal equivalents, but nothing I could find that will quickly tell me that 17mm equals pretty close to 11/16ths. So I used my Excel skills and some free time to come up with my own. You can get it here:

http://www.loyno.edu/~cbmarsh/mmtofraction.htm










I have included columns to get you to the nearest 16th, 32nd, or 64th, depending on how precise you care to get. The PDF version will be easiiest for most of you, but I've included a link to the Excel file as well, in case you want to monkey around and modify it to best suit your own needs.


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## Russel (Aug 13, 2007)

Very cool. Thanks.


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## lew (Feb 13, 2008)

Thanks, Charlie!

This will be great laminated and hanging in the shop.

Lew


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## PurpLev (May 30, 2008)

Thanx! a good reference to keep around….. now if everyone would only work in metric…. we wouldn't have these problems to begin with would we? lol…

sorry, but metric just makes sense, and working in fractions is a pain in the a$$ sometimes.


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## Karson (May 9, 2006)

Thanks Charlie. Print out nice on the color laser.


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## CharlieM1958 (Nov 7, 2006)

I couldn't agree with you more. But the old inches and fractions system just wont die.

If I'm not mistaken, it was something like 30-40 years ago when it was officially announced that the U.S. would be going to the metric system. I guess the wheels of progress turn slowly, huh?


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## bnoles (Aug 25, 2007)

Charlie,

I really apprciate your sharing this with us. This will come in soooo handy!


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## SteveKorz (Mar 25, 2008)

That's pretty handy… looks like a good reference to put in the shop… Thanks Charlie!


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## gwurst (Nov 28, 2007)

That's going in the shop. Thanks for the effort!


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## MrWoody (Jan 25, 2008)

I definitely appreciate your work on this but I won't be using it. sorry. Canada had the metric system forced on us a number of years back and one thing I have learned in that time is to never convert.
If it's in imperial measure use imperial. If it's in metric use metric. The cost of appropiate measuring instruments is very low compared with the aggravation and inaccuracy of converting. 
*Just the opinion of one ticked Canadian.* It wasn't broken and didn't need fixing.


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## CharlieM1958 (Nov 7, 2006)

LOL, MrWoody!

I'll try not to take it personally.


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## GMman (Apr 11, 2008)

I know what you mean I have sliding ruler that works well but get yourself a tape measure with both English on top and Metric at the bottom


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## Zuki (Mar 28, 2007)

Thanks Charlie. I use both out in the shop. At time I find that metric is more accurate.

The chart is super.


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## RobH2 (May 11, 2008)

It prints well in good ole b&w too. Thanks Charlie, great idea.


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## thetimberkid (Apr 5, 2008)

Thanks Charlie,

I am lucky, I have a built in converter on my cell phone

Callum


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## Radish (Apr 11, 2007)

Thanks, Charlie. Powerful tool, that Excel. One of the best things Bill Gates ever sprang on us (I recall trying to use Lotus123 with a great deal of wailing and gnashing of teeth).


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## CharlieM1958 (Nov 7, 2006)

Doug, do we *have* to say anything nice about Bill Gates? (I do love Excel, though. I've used it for years and am still finding new things I didn't know it could do.)

Callum, be careful using that cell phone in the shop!


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## croessler (Jun 22, 2007)

Charlies,

Thanks for the converter… Now I won't have to write one!


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## tenontim (Feb 24, 2008)

Thanks for the chart, Charlie. I'm sure it will come in handy. Very colorful too. You DO have too much time on your hands, to sit down and create this. Or is it too much Luzianne (w/chickory)?


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## JohnGray (Oct 6, 2007)

THIS SITE MAKES CONVERSIONS EASY.
http://www.worldwidemetric.com/metcal.htm


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## CharlieM1958 (Nov 7, 2006)

John, that's a good site. I have a little conversion calculator on my desktop that does the same thing also. But for me, the missing element that I always seem to be looking for is the mm to *fractional* inches conversion. I could not find that on the internet anywhere. (I'm sure someone will provide a link to prove me wrong.)


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## miles125 (Jun 8, 2007)

I had a guy once told me he wanted a board ripped two and two thirds inches wide. I told him i couldn't help him because it wasn't on my ruler. Lol

As for metric. I admit its a better system. I think the answer to why we haven't converted can be found in Americans general distaste for most all other things European. Now i've stepped in it!


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## CharlieM1958 (Nov 7, 2006)

How un-politically correct of you, Miles!

Besides, we don't dislike everything European. Particularly those French and Italian women come to mind (at least the ones who shave their underarms).

There…. now I've insulted Europeans and feminists in a single comment.


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## ChicoWoodnut (Dec 15, 2007)

Shame on you Charlie, now we are having the metric -v- imperial discussion again 

Too bad we don't have 12 fingers. 12 is a more natural number for archetectural measurement since it can be evenly divided in so many ways. 10 sucks since it can only be divided evenly by 2 and 5. It's multiples are just as bad. 20 can only be divided by 2, 5 and 10 while 24 can be divided by 2, 4, 8, and 12 which as you can see are all themselves divideable into halves and quarters because they don't have that ugly 5 in the middle.


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## miles125 (Jun 8, 2007)

Nice to see a comrade step in it with me!

As for converting metric to fractions. You really get a skewed result. Because theres too much rounding off going on. Lets say you decide 17mm is 11/16ths. Then when you multiply 11/16ths by say…50…you get a far different answer than 17 mm x 50. 
Getting to intimately know fractions by their decimal equivalents is the way to go for math purposes. After years i pretty much know the decimal equivalents of all fractions from 1/16th to 15/16ths in my head.


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## brunob (Dec 26, 2006)

This ones a keeper Charlie.


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## CharlieM1958 (Nov 7, 2006)

Miles, you're right about the fractions never quite being right. But I guess the applications I had in mind making the chart were more of the "in the ball park" variety. For example, I'm installing some hinges that came with screws, and the instructions say to drill 4mm pilot holes. If my bits are all fractional, what good is a decimal equivalent unless I have the corresponding bit size committed to memory. With the chart, I can look and see that 11/64 will do just fine.


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## boboswin (May 23, 2007)

Charlie did you know that Excel is just a knock off the on original Visicalc that came out when Bill Gates was teething. <vbg>
I used it on my TRS 80 Model I an II with 8 inch floppy discs.

Bob


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## niki (Mar 26, 2007)

Thank you Charlie

It's a good conversion table even for me….a Metric guy 

Working in aviation for 36 years, I'm used to work with English because…...Boeing makes the airplanes in Inches, Feet and Knots but in my "civil" life, I work always with metric…well, living in metric countries…

I can use this chart when I'm adding text to my pictures so they will be "Bilingual" (I'm posting in Australian, 2 Italian, 2 UK, Canadian, a few US and Brazilian forums).

What "Kills" me in the English measuring system is that, on my rulers and measuring tapes, the beginning is 32 or even 64th but later it becomes 16th so, if I need to measure, say, 10-5/64, I don't see it there.

Another "killer" for me is that, if I want to measure, say, 10¾", it's also not written there…I have to convert it to 12/16" and look for the lines….

If you were using everything in say, 32nds or 16th - like 28/32" or 4/16" it would be much easier for me to measure….well, I believe that for you guys it comes natural…

Regards
niki


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## CharlieM1958 (Nov 7, 2006)

Niki, I'm not quite sure I follow. On most rulers, the lines for different increments are different lengths. For example, the longest lines between inches are often the ones that are 1/4" apart. So if you want to mark something at 10 3/4, you look for the 10, then count 3 long lines over. I guess it does seem more natural if you've been doing it that way all your life.

Bob #2, I didn't know that. And I'm going to pretend I'm too young to have ever seen an 8" floppy.


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## motthunter (Dec 31, 2007)

Thanks. Lets see where else metric can help… How many hours are in a metric day? How many months in a metric year? Not everything is based on tens. Woodworking in inches makes sense when you contemplate the width of a standard blade kerf. Think about it.


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## niki (Mar 26, 2007)

Hi Charlie

Yeh, that's what happens when I talk without pics 

On the pic below, you can see that, up to 6" the graduation is 32 and from 6" - 16 so how I'm going to measure 10-5/64" but…maybe on your tapes you have a better graduation that this "bilingual" one 

And than I have to count too many lines and not only but if I have to measure 5-3/8", I have to "translate" it to 5-12/32" so, I'm writing (or reading) one number (5-3/8") and measuring different number (5-12/32") and that's a little bit confusing if I'll compare it to the Metric that I write, read and measure the same number.

I'm sure that for you it comes much more natural but for a "non-native English measuring system" it's a bit of confusing…

Now, let me give you a compliment….look at the ruler below the tape - it's made by "General" and it's "Made in USA"- I have it since 1965 and after 43 years it looks as new as it was….well, when the thinks were "Made in USA".....

Regards
niki


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## CharlieM1958 (Nov 7, 2006)

I understand now what you were saying, Niki.

Different rulers are designed for different purposes, and so there are many different ways of marking the graduations.

But think about this… A millimeter is much larger than 1/64, so if you wanted to measure something in millimeters as precisely as 10 5/64, that metric tape would not be too accurate either.


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## niki (Mar 26, 2007)

Hi Charlie

I'm only an amateur but for the last 13 years I never had to measure or cut less than 1mm…(I also cannot see less that 1mm…getting 64…  )

Maybe we (I mean - Americans and Europeans) have different thinking. I did not see Metric plan calling for xx.5mm or xx.25mm…everything is given in full millimeters.

Usually, I plan the cabinets dimensions myself (with general dimensions given by my wife - the designer) and I plan it down to 1mm.

I don't think that you'll have a problem to plan a cabinet with all the dimensions down to /32" or even /16"

The only time that I have to measure less than 1mm is when…..I align my table saw blade with the caliper… 

Best Regards
niki


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## CharlieM1958 (Nov 7, 2006)

Niki, I'm lucky if I can cut a board to within 1/16th of what I want.


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## miles125 (Jun 8, 2007)

There are quite a few examples in woodworking where we do indeed need to be more precise than nearest 1/64th or millimeter. Lets say you want to divide a 62 inch space into 45 equal increments. Or if you're metric you round off that dimension to 1575 mm and divide by 45 equal increments. Either way, for purposes of accurate math calculations, you're going to have to convert both systems to decimal places far more accurate than a millimeter or 64th to avoid arriving at an answer that is not just off, but considerably off. Just because a minute measurement is not visible on our rulers doesn't mean they don't play a crucial role in the math involved in our work.

By the way, theres a name in woodworking for less than a millimeter or 1/64th. Depending on geographic location, it would either be a "smidgen" or a "hair". Lol


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## CharlieM1958 (Nov 7, 2006)

Miles, you're absolutlely right. But I think we're talking about 2 different things.

For planning purposes, we need to be very precise. The example you give is a good one. But once you do the math, say you want to cut 45 pieces of wood that will fill a 62" space. The math tells you that each piece should be 1.37777777777 inches long. But in real life, if you manage to cut all 45 pieces within 1/64th of that figure, you are doing about as good as you can hope to do, in my opinion. Try to put those 45 pieces end to end and have them total 62". I'll bet a rusty block plane that you'll either be a hair short or you'll have to get out the sandpaper.

So my point was that, for the purpose of measuring and marking a cut line, 1/64th is more than close enough.


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## moshel (Apr 25, 2008)

you can use long ruler diagonally to get better accuracy (the same trick used for spacing dovetails). i have several rulers with 0.5mm markings on them, and i agree with niki - you cant see them or use them - they are just annoying. i find that i have better accuracy trying to mark in the middle of 1mm segment than trying to count the 0.5mm and mark on the right one.


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## Loren (May 30, 2008)

I have a Starrett Digital Tape Measure (which I damaged so I haven't
use it in awhile) - that has inches on the tape but will do metric and
inch/decimal readings. Like everybody here I am accustomed to working
in 1/8" or 1/16" but also since I build guitars I became used to using
a dial caliper which runs in 1000's of an inch.

Anyhow, the Starrett tape will do all three and it will convert and allow
you to set "zero" points by clicking a button. It wasn't expensive either -
I just haven't got 'round to replacing the broken tape… which I "dubbed" into
a spinning table saw blade a while back.


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## Grumpy (Nov 9, 2007)

Easy way out Charlie, just use millimetres. LOL


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## CharlieM1958 (Nov 7, 2006)

Ya know, Grumpy, I'd be perfectly willing to go along with the whole metric deal if we could just* change everything *and not be stuck dealing with two systems.


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## boboswin (May 23, 2007)

What Charlie said!

Bob


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## Grumpy (Nov 9, 2007)

Charlie, The conversion part is not too bad. It's the thinking in metric thats the hardest. Like thinking gas per litre as against per gallon.


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## Roz (Jan 13, 2008)

Thanks Charlie,
I can use this. Terry


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## itsme_timd (Nov 29, 2007)

Great chart, thanks - I love Excel for this stuff. I have a set of calipers that do inches and MM and I'd be lost without them. I use them all the time when trying to find a fractional drill bit that's 'close enough' for my pen tubes!


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## Allison (Dec 31, 2007)

Wow charlie this is great!!! I have needed something like this for a very long time. Great! it is going right up to my shop!
PEACE!!!
I not only can use this. I will use this!


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## CharlieM1958 (Nov 7, 2006)

Glad to have been of service!


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## ryno101 (May 14, 2008)

Thank you so much!!!! I've been working on a sketchup plan for a kayak I'm hoping to build soon, and all the plan dimensions are in mm's, this is a HUGE help.

Thanks!


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## mondo (Oct 30, 2009)

Where did you learn Math Charlie? I checked your chart out.. 1/4 of an inch is .25!!!!! not .2362!!! After seeing that one conversion. I wondered where you learned how to add?


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## davidpettinger (Aug 21, 2009)

Hey Guys, I've been using this chart for a while, I call it close enough for government work!!!!

http://www.penn-union.com/ref%20material/Millimeter%20Decimal%20Fraction%20Conversion%20Chart.pdf

I downloaded it along time ago and have by my drill press on the wall along with this chart.

http://www.csgnetwork.com/drillsizeconvert.html


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## Roger Clark aka Rex (Dec 30, 2008)

The Metric measurement System was adopted by the United States as the ONLY legal method of measurement in the United States way back in the 1800's (early I believe ) where it was made into Law.
The Imperial Measurement System is an insane system where units defy logic and are based on obtuse objects:
A foot is the length of a Roman Soldier's sandal, the Yard is a measurement from the King's nose to his outstretched index finger tip. There are many differnt fractions of an inch to 1 inch, there are 12" to a Foot, there are 3 Feet to a Yard, 22 Yards equal one Chain - and we have'nt even mentioned decimals of an Inch!
The Metric ISO system is MUCH SIMPLER and MORE ACCURATE and is based on Physical and verifiable measurements. Linear measurement is based on the Meter (Metre) and if you can multiply and divide by 10 you have it made to get to all the other linear units. There are NO fractions in metric, but there are fine measurement deciimals (Deci is a metric term).
I can work in both systems and the metric system is hands down the best. And being it's the law, we should be using it. Of course we want to be different, so now we are compatible only with Nigeria - the only other country that uses the Imperial system in the world. But the metric system is used in the US secretly: 35mm film is not specified as1-3/8" film. Ever had had any medical injections that were in fluid ounces? Ever smoked a 100 long cigarette? - the 100 is for Millimetres (also the 120 cigs). Do you think NASA or air plane makers design and build vehicles to the measurements of a Roman Soldiers Foot? How much more confusion do we need?, after all a 2×4 is NOT 2"x4" is it?, so why do we call it a 2×4? In metric lumber you get a 90×50 and guess what?, it's 90mmx50mm - no false size claims of what the lumber WAS before it was cut to a stud!!! So we get charged by a 2×4 which is not a 2×4, so why not just call the lumber an 8' foot log because that was the size it was to start with. lol.
I really don't kow why we are so against changing to a better system and I am sure we lose some oversears trade by using an "oddball" measurement system. Perhaps we should be operating to the full Measure of the LAW??? lol


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## TopamaxSurvivor (May 2, 2008)

Yeah, but I'll use 1/8 meter if i want to, you can't do anything about it ;-))


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## Roger Clark aka Rex (Dec 30, 2008)

Hey Topamax, How are you doing?
I guess you're on of those people who won't give an inch!, but I'm the one that won't give a millimeter!!! lol
Got a true story to tell re: metrication. A while back when the USSR was in business, they ordered a load of wheat from the US because they had crop failures. The US took the order and a ship showed up in the USSR filled with the grain order. The soviets were not pleased because they had ordered X amount of metric tonnes and had been sent only X amount of Imperial tons. The shortfall was another ship load which had to be sent to fullfil the order as both countries and International Law specified ALL contracts MUST be made in the metric system. We lost our ass on that one.
Now go have a great weekend. ;-))


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## TopamaxSurvivor (May 2, 2008)

Why convert? If you're uisng metric, use metric, forget the conversion, it's easier than moving back and forth.

Anyways, i read a while back why railroad tracks are the width they are. It goes all the way back to the width of 2 Roman Chariot pulling horses behinds. The wheels had to be so with to accomodate 2 horses, but no wider than necessary. The history went up through the ages of all the inventions that were based on the previous item. It all made sense as they progressed.

Anyway, i still like my fractions for meters) It keeps one's math skills sharp; ie, 1/8 meter = 12.5 cm or 125 mm, right ?


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## Roger Clark aka Rex (Dec 30, 2008)

Just in case
The "key" to using the Metric ISO system is NOT to convert from Imperial measurements, a redesign in the metric system is the right way to go, then you don't have to bother with 2 systems. If you need to go less than a millimeter then you use Micrometers. Use the letter designations as a guide: Centi = 100 as in cents, Deci = 10 as in a dime (10cents) Milli = 1000 - therefor a Millimeter equals one thousandth of a Meter. Nano Technology relates to Nanometers (very small). You can find engineering drawing that are dimensioned in Millimeters and all you have to do to make 1000 mm to one Meter is to divide it by 1000 = 1 Meter or divide by 100 to get Centimeters or divide by 10 to get Decimeters, in other words just add/move the decimal point. In Mechanical Engineering you will find a lot of metric usage as it is so precise and does not lend itself to dimension errors, but I guess in woodworking if you make something to the nearest spliter, then that is considered good. If you use fasteners say a 1/4-20 bolt you have to find a 7/16" wrench to tighten it, while in the metric system an M6 bolt takes a 6 mm wrench - makes sense???
Anyone got a 9mm handgun? or an M16 or maybe a AK47? - all metric ammo! Tanks and warships use metric sized ammo (105mm etc). Your med pills are in grams while temperature has a stupid measurement where 32 = freezing and 212 = boiling where in metric Celceus 0 = freezing and 100 = boiling. It is time we got compatable with the rest of the world (sorry Nigeria) and make the change for our own benefit - sadly many many years late. After all the British Imperial System was abandoned by the British nearly 30 years ago in favor of the International Metric ISO system …..makes you think? Kilos and grams don't just belong to hard drug busts.


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## Roger Clark aka Rex (Dec 30, 2008)

Hey Topamax,
You go with what you feel comfortable with my friend, most of us old farts are too much set in our ways and as stubborn as a mule. Ain't old age great? 
The history is always very interesting showing reasons how things go to be like they are. One of the interesting things is that the Imperial Ton is heavier than the US ton and that the Imperial gallon is larger than the US gallon - that's why we have 55 gallon oil drums while the Imperial (same capacity) is 50 gallons.
On the lighter side I have found that cooking with metric measured ingredents makes a repeatable recipe better - yeah I do use 1.2 mil foil and clean up with 1 mil trash bags.
Well, I'm off to bed now as I have to be up at 0700 hours.


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## patron (Apr 2, 2009)

so what do we do with the c… hair ?
it seems to get into all the systems !
and is universally understood .


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## Roger Clark aka Rex (Dec 30, 2008)

Hey david, what are you doing up so late? - you must be converting inch fractions to millimeters. lol
The only reason I stayed up is my meds won't let sleep right now. 
I did hear that the folks in NM were still using cubits as their standard measuring unit. I'd meet you for breakfast half way, but it would well after lunchtime by then. Now go to bed and get some rest. I'll stay up and monitor the LJ site for you until daylight.
You have a wonderful weekend and keep smiling.


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## patron (Apr 2, 2009)

not up till late ,
woke up at 1:30 .
nowdays sleep is in nap form ,
maybe 3 hours tops !
whenever .


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## Gene01 (Jan 5, 2009)

Thanks Charlie.
As to the argument between advocates of the two systems, I won't offer an opinion….except to lament that I wish tool manufacturers and plywood manufacturers would get their acts together and settle on ONE system and stick with it.


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## CharlieM1958 (Nov 7, 2006)

Dave, thanks for defending my honor.  Mondo, the purpose of the chart is to start with a millimeter measurement and give the *closest* fractional equivalent. In the case of 6mm, you'd have to get into 128ths or beyond to get closer than 1/4.


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## Roger Clark aka Rex (Dec 30, 2008)

Charlie,
Your chart will be of great use and it is well laid out, but you need to add convertions for tolerances: Like -
Tad
Hair
Smidgen
Close
No Cigar 
No Way
Sheesh
OMG
Idiot
Why

Etc. lol
Well done Charlie, your chart will also help folks visualize metric sizes so they will get to know "round about" equivalents. This is certainly a great help.


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## a1Jim (Aug 9, 2008)

Thanks Charlie


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## CharlieM1958 (Nov 7, 2006)

Speaking of hair… there are three hair measurements: H, CH, and RCH.

If any of you do not know what these abbreviations stand for, I will *not* be providing any further clarification.


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## ROY53 (Sep 12, 2009)

I use a digital caliper that will switch from fractional to decimal or metric with a push of a button. Don't recall where I got it, but I use it all the time.


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## huff (May 28, 2009)

Charlie, did you every think you would open such a discussion on your forum? LOL. Roger you forgot one: "Close enough for Goverment work"! 
I feel guilty. Think I need to throw all my tape measures away, burn my lumber, shred my drawings and pick another line of work! LOL (I think).
Anyway, Thanks Charlie.


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## Roger Clark aka Rex (Dec 30, 2008)

Huff and Charlie,
My (serious) input on this discussion is based on personal experiences. As many of you know I'm an English American (well why not?). My work background has been mechanical design and CAD with a lot of precision engineering drawings. I went through the metric conversion in the UK in 1971or 1972 and at first I was not happy to do it but when I found out how easy and precise it was, I changed my attitude and got into it.
About 4 years later I was doing contract work in Africa - mech eng, and there they were trying to use both systems. With my contract was *fixing* (a colloquial colonial expression) to expire in a few months I answered an ad for a mechanical design guy who was fluent in the Imperial and Metric systems. I answered the ad and was offered a job Teaching college drafting and design students to go metric; I was also the campus guru on metric ISO standards - at that time there was a government push to get the US into using the metric system.
The government backed off the metric push due to public complaints that purchasing gas in Liters would be too difficult for them - but don't most people get $10, $20 worth or so of gas, so whether it is delivered in gallons, liters or spoofulls it really does not matter - you get the amount that you for! I did the teaching stint for 8 years, then moved on to 100% CAD.
It's not really practical to hang on to the Imperial system as all but one other country still uses it as their standard. If we export, we have to go metric and I don't think people realize just how much $'s are lost or wasted by clinging on to an obsolete system. FDR said the only thing we have to fear is fear itself - so we should not fear change.
Ever looked at - say a box of detergent or cake mix or such? - they give 3 different measures of what the box contains, wouldn't it be nice and easy to have just one?
True story: When I came to the US, after a while I purchased a house and decided to add a wall, so I went to get lumber for the job - 2×4's. When I got home I was horrified to find the lumber was the wrong size as I had drawn up a plan using 2×4's. I headed back to the store and complained that they sold me the wroong size lumber - that's when I found out that a 2×4 is *not* a 2×4 but a 3-1/2×1-1/2! Being from England I just had to ask what size was a 1/2" bolt was then!
And to quote 2 of my favorite and dearly missed people:
"And that's the rest of the story" 
"And that's the way it is"

Have fun and take care


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## TopamaxSurvivor (May 2, 2008)

Nice chart Charlie!! Great work. Sorry i messed up your thread making wise cracks about using a fraction of a meter ;-))

You guys still missed the 2 most important units of measure the old time gunsmiths used in the 19th century: a trifle and a scoche.


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## jimc (Mar 6, 2008)

It's the same as a foreign language - as long as you have to translate everything to your prime language, you will never be comfortable. If someone tells me a widget is 32 cm long, I have no clue whether it is 1" or 20". I have to say, "ok, 2.54 cm per inch, 32/2.54 - oh ********************, where is my calculator. OK, 32/2=16, 32/3=~11, so it must be about 13-1/2"". Having been in the Navy, I did use the metric system some but never enough so I became comfortable with it. Same thing with km - I know it is 1000M, and since a meter is 39.36 inches, which is about a yard, 1KM is about 1000 yards, which is about 2/3 mile. Weight is even worse - 454 grams per pound… uh, what's an ounce? What do you use when cooking - what's a cup or teaspoon in metric??? I have no idea!

I agree that we should fully adopt the metric system for its preciseness but don't see it happening any time in my lifetime.


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## niki (Mar 26, 2007)

I would not suggest to convert Metric to English for any job that requires measuring….

An Inch will never convert round to mm and a mm will never convert round to Inch…

Just a small example 1/2" = 12.7mm…..we don't have any means to measure .7mm (the best ruler will have a graduations of .5mm that is very difficult to see and usually we work in whole mm unless it's for NASA and they also work in metric)

Another one, 13mm = 65.511811/128" that you can not read anywhere and you shall have to round it to 65/128" (if you can see it and if it's practical)

I think that the accumulative "left overs" will lead to a big mistake at the end of work…the best is to stick to the plan measurements, be it Metric or English…

Jim
Just for you, we measure Weight in Grams (1000 grams = 1 Kg) or Kg or Ton (1Ton = 1000Kg)

As for volume, the smallest unit is Milliliter…(1000ml = 1 Liter)...the next is CC (Cubic Centimeter - used usually for car engine volume)

As you can see, the pattern is constant for weight, volume and distance and it goes - Milli - Centi - Deci and Kilo….we start with the smallest unit and always multiply by 10 to get the next size unit (but, I'm sure that you know all that)...even though, the woodworkers are using only mm and it sounds very funny (even to me) that the cabinet length is 3,450mm instead of 3.45 Meters…

But, if you are used to the English system and live in a country that almost everything is English, I'm sure that it will be easier for you to think and work in English measuring system….I also would not change my Metric even if the English is easier.

BTW, in Europe, there are at least two things that are measured in English - the iron pipe diameter (the plastic ones are measured in mm) is measured in "Zall" (Tsall) and the TV screen is also measured in Inches…

Best Regards
niki


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## Gene01 (Jan 5, 2009)

Don't GARA which system is used. Just make a router bit that will cut a dado in which a standard piece of plywood will fit. Yeah, I know about jigs but, why do we have to use them? I cant even use my stacked dado blades, with or without shims, to get a groove(with one cut) for anything but BB plywood. 
I'd gladly outfit my shop with metric tools….or inch tools. If someone would just make the materials standard the same as the tool standard. I just got the Kerf Maker I ordered. $60.00 just to cut slots in odd sized plywood. RIDICULOUS! 
Rant off.


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## TopamaxSurvivor (May 2, 2008)

If materials were standard sized like they used to be, the CEO bonuses would have to go back to those standards too )


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## ventifact (Jan 14, 2010)

One inch is EXACTLY 25.4 millimeters.


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## BritBoxmaker (Feb 1, 2010)

Nice work, Charlie but isn't it time you guys caught up with the rest of the world and started using the metric system? lol

I have been doing these conversions most of my life and find its best to use either system for a project but stick ONLY to the one you started with. Spacecraft have been lost through neglecting this simple expedient. Not to mention woodwork projects and fingers.


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## SCOTSMAN (Aug 1, 2008)

When I bought the incra jig I got a friend of mine who was travelling to the good old US to buy me such a calculator not cheep but works decimals to fractions etc so will convert 2.3/4 to mm's which from the top of my head is nominally 69mm correct me if I'm wrong. and it shows exactly that 2.3/4 not 2.75Alistair


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## Dez (Mar 28, 2007)

Add another thanks to the list from me!


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## NBeener (Sep 16, 2009)

I love stuff like this, but … then … I'm really strange, that way ;-)

Thanks, *Charlie*!


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## Dennisgrosen (Nov 14, 2009)

thank´s Charlie
and every body ells who take there presures time
to do theese kind of work and share them

Dennis


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## WillyWally (Apr 10, 2009)

Yike, all this fuss over fractions and little tiny stuff I can't see any more. I settle for a split pencle line. How wide is a pencle line?


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## Roger Clark aka Rex (Dec 30, 2008)

WillyWally,

Would that be a 0.3mm, 0.5mm, 0.7mm or a 0.9mm mechanical pencil ? lol


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## TopamaxSurvivor (May 2, 2008)

A lumber pencil can be about 1/4" ) After all Lumber Jocks use Lumber Pencils don't they?


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## daveator (Jun 20, 2011)

Just stumbled across this very useful table…Thanks for creating it.


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## roman (Sep 28, 2007)

you can buy tape measures with imperial on one side, and metric on the other ?


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## 47phord (Apr 10, 2012)

Thanks! I wish we would just adopt the metric system here, nothing is more frustratiing than trying to divide 7/16" by 4 or something equally obtuse (no math pun intended). When I bake, I always weigh things out in grams-I find it's alot easier to deal with. But, baking formulas in metric are easy to come by, woodworking plans-not so much.


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## TopamaxSurvivor (May 2, 2008)

With a cm being .3937", it shouldn't take long to convert most plan dimensions to metric.


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## Charlie5791 (Feb 21, 2012)

I have a "yard stick" marked imperial on one side and metric on the other. Got it at Lowes. I'd love a better quality one. Also have a tape measure marked with both. I'm really close to the border (7 minutes to the Queenston-Lewiston bridge). If I stop at a Home Depot or something next time I'm in Canada, will I see a better selection of metric measuring tools? Or….. maybe not Home Depot, but somewhere else? I know we have some LJs from the area. Thoughts?

I started getting these metric measuring tools when I was building the drawers for our kitchen. I used Blum Tandembox hardware. It was just easier to do it all in metric. Now I prefer it.


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## MontanaBob (Jan 19, 2011)

Thanks-This chart will be in the shop today..


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## CharlieM1958 (Nov 7, 2006)

It's kind of funny how I posted this over 4 years ago, and all of a sudden it's got new life.


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## Swyftfeet (Jun 15, 2012)

25.4mm to an inch… I always just think "Christmas for my money"


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## Dennisgrosen (Nov 14, 2009)

thats just show people are happy for the work you have done Charlie 

Topa just multiply with 2,54 and you have the inches in cm and mm

Dennis


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## BRAVOGOLFTANGO (Nov 30, 2012)

Just what the Dr. ordered today, thank you.


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## stefang (Apr 9, 2009)

Bless you Charlie. I just saw this one a little late, 1650 days late to be exact. Nevertheless I want to thank you for this wonderful gift. A very useful conversion chart.


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## CharlieM1958 (Nov 7, 2006)

I'm glad folks are still running across this and finding it useful!


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## RonInOhio (Jul 23, 2010)

Thanks Charlie.


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## runswithscissors (Nov 8, 2012)

We are gradually coming around to metric. Most people know a 12" ruler is close to 30mm, have one or more sets of metric wrenches (which fortunately almost always work on SAE nuts and bolts), as almost everything nowadays automotive is metric. You get used to it. Mr. Woody is right, it's better if you don't have to make the conversion. This means familiarizing yourself with common measurements so you don't always have to be converting. And dividing/multiplying mms is much easier than doing it with fractions. Less chance of making a mistake (quick! what's 11/16 plus 7/8" minus 3/32"?)

By the way, I have as much trouble with decimal inches when my tapes and rulers are fractional. I'm glad we now have digital calipers that give both. Oh, I have somewhere in my pile of stuff a tape that has both metric and inches. These aren't hard to find (I mean, mine is, but in general, you know).

That's not to say you didn't make a useful tool, Charlie. I'll probably copy it off myself for the shop.


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## roman (Sep 28, 2007)

its like a language

immersed

no conversion, no second thought

its like being bilingual


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## roman (Sep 28, 2007)

looking in a book of translation from one language to another is such a slow painful process for both listener and speaker

im so happy to be bi-lingual and betting the chart helps many in translating hard to easier ?


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## TopamaxSurvivor (May 2, 2008)

runswithscissors, Ask me when I'm not on the edge of a migraine.


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## BRAVOGOLFTANGO (Nov 30, 2012)

It also inspired me to pickup a new app, $6 for my android phone from Calculated Industries, the Measure Master Pro will convert (instantly) m, cm, mm to yds, ft, inches & vice versa in fractional imperial values or metric. That with your hardcopy now in my project shop binder is a nice shop add, so again thank yous sir.


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## oldnovice (Mar 7, 2009)

In my last employment all our scales, form 6" to 24", were marked in fractional, decimal inches, and cm/mm so when I left, a few of them got mixed up with my belongings and I never had the chance to return them!

These scales were supposed to be part of the"move to metric" yet all our prints were dual dimensioned in decimal inches and mm. I think the movement was somewhat halfhearted!


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## stefang (Apr 9, 2009)

I don't really need inches. Since moving to Norway so many years ago I have been happily using the metric system. It is super easy because everything here is metric. I realize that it's quite a different story for those who have a mix of standards. They have the same problem in the U.K.

When I write posts for LJ I try to describe the measurements in inches, but this means converting from my metric to the imperial measurements. Charlie's chart will help me with that. I have digital calipers and angle finders, but they don't have fractions and neither does my conversion tool on my MAC.

There is a website that I have bookmarked that converts decimal inches to fractions at the following link. http://www2.whidbey.net/ohmsmath/webwork/javascript/decin2fr.html


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## b2rtch (Jan 20, 2010)

Thank you very much for posting this, I was born metric.
For me fractions are a real headache.
As an maintenance tech, I use tools from this webpage:

http://www.engnetglobal.com/tips/


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## RMHutchins (Aug 27, 2011)

Thank you! This was very helpful. I'm glad you took the time to prepare this


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## rickyswoodcrafts (Mar 10, 2013)

This chart is the bomb!

I am DW and do a lot of sewing & quilting. The internet is good for going to a site and having a program calculate (or goggle has a calculator) but just having a simple easy to read chart is so much easier.

Hanging on my wall and will probably do like another commenter and laminate.

Thanks from DW Donna


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## distrbd (Sep 14, 2011)

I worked for 35 years in metal manufacturing in Toronto,Canada and all measurements were in imperial although we are supposed to have already converted but as far as metal manufacturing/fabrication is concerned it was all in imperial system,we would see metric off and on but never needed to convert .
I buy most of my rulers,measuring tools from the US only because it's in inches on both sides.


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## NotToDay (Feb 15, 2013)

Here is another one from Engineering ToolBox
you can click on the pdf conversion and save or print it 
http://www.engineeringtoolbox.com/inches-mm-conversion-d_751.html


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## tme4tls (Mar 21, 2011)

Or: You can go to www.WorldWidemetric.com for an easy conversion. Converts liquid measurements as well.


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## runswithscissors (Nov 8, 2012)

You can also get a digital caliper, quite cheaply, that will give you fractional and metric either simultaneously or by toggling between them. I have never found decimal inches to be useful in woodworking, just confusing.


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