the metric challenge

[jpdorn]

every once in a while i set my 6" rule up to my work backwards, displaying the metric side rather than the imperial. when i do that, there's a brief realization of peace and beauty as i reflect on the wondrous system of measurement we know as metric. the zen of that moment is quickly interrupted as i flip the rule over and try to remember what i had calculated a third of 41/32s to be..

i'm a huge fan of relative dimensioning when possible but sometimes you gotta bust out the rule.

enough, i say..

my next project will be designed and built using meters and all its little friends.

any of you other slaves to the imperial system up for the challenge?

anyone else already made the switch?

[petersb]

information overload information overload does not compute does not compute

[iSawitFirst]

I'm all for going metric. My only problem is I can't gauge the size of mm's and cm's. Like, how long is a board that's 300 cm? 750mm? It makes it hard to design without constantly using conversion tables. Plus, using metric tools for projects with standard dimensioned lumber can be a bit of a challenge.

But, for ease of use laying out projects, you can't beat the metric system.

[Vic]

I have the same problem with visualizing in metric. The same applies to celsius. I know what 4 feet looks like and how warm 75 degrees is, but don't have a clue how big anything other than a meter is or 0 celsius is cold.

[wilburpan]

I'm all for going metric. My only problem is I can't gauge the size of mm's and cm's. Like, how long is a board that's 300 cm? 750mm?

I agree. Metric can't be beat for dividing things up. I'm pretty good with metric for smaller dimensions: 1/4" is about 6mm, which makes 1/2", 3/4", and 1" easy. 1 foot is about 300 mm. But for larger measurements I just don't practice with it enough to have a good idea what to expect.

[kpetten]

This is something I have already started to do. I have a metric readout for my planer, and whenever possible I buy measuring tools with both.

Most chisels and sheet goods are also already metric. The reason why 3/4" plywood is not quite 3/4" is because its 19mm(in Canada anyhow).

I find that I make less mistakes when I'm adding real numbers instead of fractions. 4 1/4" + 5 25/64" + 14 13/32" = a big mess for my brain. 101mm + 126mm + 1704mm =1931mm, easy even for my brain.

If need to rip a board 300mm, then rip a board 300mm. What difference does it make how many inches it equals if you are workingand measuring in metric?

The only problem I can see is working from a imperial drawing and building metric, or vice versa. But if you are designing the piece or have a metric drawing to work from, its a breeze.

[TheSwede]

Ladies and Gents,

I have to say I'm impressed by your endevours. Coming from a country that have been using the Metric system for at least 100 years I have no idea what it is like to use anything else, but being a frequvent visitor to Amercian woodworking sites, I can reqocnice your problems.

I have the same issues with the imperial, I cant understand a thing, fractions here and fractions there...

Now I guess I'm bious in this question but you have to love the simplicity of the metric system and the use of a 10 based scale, it's all decimals and dividing or adding is easy.

Not to step on anyonce feet, when are you leaving the imperial system and comming over to "our" side ?

[TheSwede]

my next project will be designed and built using meters and all its little friends.

I just saw it, LoL Its freinds, I guess you are refering to Centimeters and Milimiters.

Good luck in your effort!!

[Beechwood Chip]

If need to rip a board 300mm, then rip a board 300mm. What difference does it make how many inches it equals if you are working and measuring in metric?

If Iknow it's 300mm, there's no problem. And, if I am measuring, then it's no problem. It's when I'm estimating that there's a problem. At this point, I can look at something and pretty accurately estimate it's length in feet and inches. To estimate it's length in mm I'd need to pull a tape measure out to the approximate length and read it. Or, estimate it's length in feet and then do the math to convert.

I mostly use relative dimensioning in the shop, and measured units when I'm buying stuff. And, since everything I buy is in feet and inches, it doesn't do me much good to work in metric - I just have to convert anyway. When I do measure stuff in the shop, I'm often multiplying or dividing by two, and imperial is really convenient for that.

[Dan S]

All you need to know is 25.4, as in 1 inch equals 25.4 millimeters. with that and a $1 calculator, you can get all the info you need to infinite precision.

[kpetten]

If Iknow it's 300mm, there's no problem. And, if I am measuring, then it's no problem. It's when I'm estimating that there's a problem. At this point, I can look at something and pretty accurately estimate it's length in feet and inches. To estimate it's length in mm I'd need to pull a tape measure out to the approximate length and read it. Or, estimate it's length in feet and then do the math to convert.

I mostly use relative dimensioning in the shop, and measured units when I'm buying stuff. And, since everything I buy is in feet and inches, it doesn't do me much good to work in metric - I just have to convert anyway. When I do measure stuff in the shop, I'm often multiplying or dividing by two, and imperial is really convenient for that.

I find it easier to do any math with whole numbers. Most of the drawings/blueprints for my day job is in metric, but there is still a lot of imperial measurement in the materials we use.I know how one measurement roughly relates to the other without thinking of it from doing 400 times a day.

If I could do a project and only use metric from start to finish, it would have less mistakes, and less waste.

Most millwork shops use some combination of the 32mm system. And if you use cup hinges at all,installation will go mush smother if you use metric bits and measurements. All the sheet-goods are also metric. If you build, or work in a shop that makes, frameless cabinets, you are well used to the metric system.

I'm not saying its for everyone, but I like it.

And don't get me wrong..... I still like my backyard, quarter pounders and my uncle Miles.

[jhl.verona]

The rot has set in. Resist at all costs. Look what happened in the UK. Suddenly gas pipes became 12.7mm in diameter, milk came in 568ml bottles, and sausages in 454g packs. Oh the shame of it all. We should never have given up the pounds, shillings and pence (1 pound, 20 shillings, 240 pence).

Imperial measures are designed to make you think. A 17/64" measurement is poetic, a work of art, precise - it's not your common or garden 6.75mm.

There is sound reasoning (which we mere mortals cannot understand because forever lost in the mists of time) why there should be 14 pounds in a stone, and 16 ounces in a pound. Or 1760 yards in a mile, and 4,840 square yards in an acre.

Life just isn't the same without the yard, chain. league, fathom, acre, or furlong. "And as they round the bend towards the last 201.168m, Red Rum leads..."

They'll be decimalising time next. Fight back, go FFF. Now we're talking, wood density in firkins per cubic furlong anyone?

John

[TBaiga]

what? no cubit advocates?

[Beechwood Chip]

There is sound reasoning (which we mere mortals cannot understand because forever lost in the mists of time) why there should be ... 16 ounces in a pound.

OK, I know that no one cares, but this is one of my favorite stories. The "ounce" and the "inch" come from the same Latin word (think of pronouncing "ounce" with a soft "C" like in "cello".) The Romans didn't like fractions any more than the Babylonians did, so they liked to use round numbers that could be divided evenly by 2, 3, 4, and 5, like 60 minutes and 360 degrees. But no one has 60 fingers, so sometimes they compromised and used 12, which at least is divisible by 2, 3, and 4.

And that's why a foot is 12 inches, a pound is 12 ounces, and a day is 12 hours (a night is 12 hours, too).

OK, I hear you all saying, "But, no one has 12 fingers!" Next question!

OK, I hear you all saying, "But, a pound is 16 ounces, not 12! What's up with that?" Ah, good question!

The Roman Empire had contracts to pay soldiers, etc, in ounces of silver, gold, etc. And the Empire was running out of money. So, they redefined the ounce to make it smaller. They made it a 13th, then a 14th, etc, until it hit a 16th of a pound, and then the Empire fell. Since the Empire wasn't paying anyone in inches of anything, the inch stayed 1/12th of a foot.

How's that for the mists of time! I bet the metric system doesn't have any cool stories like that!

Note: I might be making this up.

[Gregory Paolini]

Well.... Seeing as the bulk of the cabinetry I build is Euro in nature, I've embraced metric, as well as Imperial. Sometimes my mind things metric while my hands (And saw fence) work in inches, and visa versa. Although, I generally keep my 35mm's, and 32mm's in good shape...

[jpdorn]

you guys are funny..

swede, my wife wanted me to thank you for loaning us forsberg again. he's in town skating with the avs at the moment.

wilbur, this is kind of your fault this all started with the infection of japanese chisels. '6mm? how the hell am i supposed to dimension a mortise/tenon for a 6mm chisel?!? duh, measure in mm and use the rule of thirds.. wait! what if i did the whole project that way..' clearly, the decent thing for you to do would be to join me.

now i just have to find a good pocket tape in metric and buy another 12" starrett combination square.

and so it begins

[TheSwede]

You are most welcome, and I hear Forsberg is not making a fool of himself either, I heard he won some prestigious award, perhaps I got it wrong

Who says we don’t have interesting stories about the metric system, they may not be about ancient roman empires but of precision and science

The official definition of 1 Meter is the distance light will travel in vacuum during 1/299 792 458 parts of a second

How’s that for precision in your next project?

[MTR]

I have started to mix and match measurements on my projects. I started to get into the 32mm system and along with a Domino it kind of forced my hand. I got a Fastcap tape that reads in both metric and inches to help out the visualization of what 300mm is. I agree that is the biggest stumbling block. I also have a Fein and Festool folding rules that I use for most of my layouts that have both measurements on it.

As far as precision - are we talking about converting from International-foot or US-Foot?

fastcap tape: http://www.mcfeelys.com/product/FSC-403/FastCap-MetricStandard-Tape-Measures

Folding rule - http://www.highlandwoodworking.com/festool6ft2mfoldingrule.aspx

[flairwoodworks]

Living in BC, I'm used to some metric. I drive 3km to buy 4L of milk and a 54g chocolate bar but have to be careful when it's below 0 degrees Celsius. However, I don't know what 640 cm is without first converting it to inches. My shop is mostly inches with the exception of a 35mm drill bit, 8mm spiral router bit, backside of a couple rules, and Festools (and plywood if it is really metric - someone once told me that the sheets of plywood at the bottom of the stack are thinner than those at the top...).

I have the same problem with visualizing in metric. The same applies to celsius. I know what 4 feet looks like and how warm 75 degrees is, but don't have a clue how big anything other than a meter is or 0 celsius is cold.

0 celsius is cold. It's actually the freezing point of water. That makes it easy.

Who says we don’t have interesting stories about the metric system, they may not be about ancient roman empires but of precision and science

The official definition of 1 Meter is the distance light will travel in vacuum during 1/299 792 458 parts of a second

So, are you saying that even when dealing with the Metric system, we still can't eliminate fractions?

[Pete Bennett]

The rot has set in. Resist at all costs. Look what happened in the UK. Suddenly gas pipes became 12.7mm in diameter, milk came in 568ml bottles, and sausages in 454g packs. Oh the shame of it all. We should never have given up the pounds, shillings and pence (1 pound, 20 shillings, 240 pence).

Imperial measures are designed to make you think. A 17/64" measurement is poetic, a work of art, precise - it's not your common or garden 6.75mm.

There is sound reasoning (which we mere mortals cannot understand because forever lost in the mists of time) why there should be 14 pounds in a stone, and 16 ounces in a pound. Or 1760 yards in a mile, and 4,840 square yards in an acre.

Life just isn't the same without the yard, chain. league, fathom, acre, or furlong. "And as they round the bend towards the last 201.168m, Red Rum leads..."

They'll be decimalising time next. Fight back, go FFF. Now we're talking, wood density in firkins per cubic furlong anyone?

John

I know just what you mean John!!!! I've been using this metric stuff since 1972 and still I can only visualize in feet and inches. If and when I weigh myself (Rare) I still have to take the kilogrammes and convert to stones etc. before i can make sense of it.

[Simon]

In Canada, the metric system was adopted a while back. Even so, many are fine when it's time to purchase something at the food store or to find out how cold or warm it is outside. But when it comes to woodworking, not that many work in metric.

It is not the mesurements themselves that are the problem but the materials and tools. It is not easy to follow a plan when all your plywood is 3/4 or 11/16 inches thick. You can always say that the plywood is 1.9cm but is it really? In fine furniture, this may end you with a shelf that does not fit in a dado or is too loose. Even if there is a tiny difference, it adds up in the long run.

What about all the 1/4, 1/2, 3/8 and 3/4 inch router bits you own ? Are you going to purchase them in metric now ? Are you going to buy metric T-Nuts and Forstner bits for your jigs ?

I have seen a few of you mentionning the confusion between millimeters and centimeters. Well, it happenned to me. I had a piece of wood that needed to be 112cm. My tape measure is graduated in millimeters so I cut at 1012mm. See my mistake ? my piece was exactly 108mm too short.

In conclusion, I work in metric when I absolutely have to.

[TheSwede]

So, are you saying that even when dealing with the Metric system, we still can't eliminate fractions?

offcourse you can, it is simply a mather of adding a zero at the end

If a board of ply is 1.22 meter it is also 122 centimeter and equally 1220 millimeter

we use decimlas, not fractions, for example 10,5 millimeters, in a fraction system that would be 10 1/2 (ten and a half) which would be simply enough but it gets messy when you want to express 10,7 millimieters with fractions.

The metric system is also refered to as the decimal system, everything is based on 10

you goto to love the simplicity of it, when you think about it, this is a natural way for humans to calcualte as we do have ten fingers.

[wilburpan]

wilbur, this is kind of your fault this all started with the infection of japanese chisels. '6mm? how the hell am i supposed to dimension a mortise/tenon for a 6mm chisel?!? duh, measure in mm and use the rule of thirds.. wait! what if i did the whole project that way..' clearly, the decent thing for you to do would be to join me.

It gets worse with Japanese chisels. The traditional unit of measurement is called a shaku, which is pretty close to a foot. A shaku is divided into 10 sun, and a sun is divided into 10 bu, which is very close to 3 mm. So your 6mm chisel is actually 2 bu.

So when you see Japanese tools being measured in mm, it's probably really in these measurements, converted for your convenience. Although it's probably not really 6 mm, any more than 3/4" plywood is really 3/4".

It is not the mesurements themselves that are the problem but the materials and tools. It is not easy to follow a plan when all your plywood is 3/4 or 11/16 inches thick. You can always say that the plywood is 1.9cm but is it really? In fine furniture, this may end you with a shelf that does not fit in a dado or is too loose. Even if there is a tiny difference, it adds up in the long run.

What about all the 1/4, 1/2, 3/8 and 3/4 inch router bits you own ? Are you going to purchase them in metric now ? Are you going to buy metric T-Nuts and Forstner bits for your jigs ?

Well, if these days you have to buy plywood specific router bits, why not metric ones? Those 1/4", 1/2", and 3/4" router bits aren't going to be useful in that application anyway.

[jpdorn]

i honestly can't remember the last time i cared about the diameter of a router or forstner bit. i just don't use them that way.

interesting wilbur. i knew about shaku but didn't know that chisels were actually dimensioned as such, vs. mm.

no matter. i figure the best thing that could happen would be for me to get stuck and learn to measure even less than i already do.

[Bob Rozaieski]

OK, I know that no one cares, but this is one of my favorite stories. The "ounce" and the "inch" come from the same Latin word (think of pronouncing "ounce" with a soft "C" like in "cello".) The Romans didn't like fractions any more than the Babylonians did, so they liked to use round numbers that could be divided evenly by 2, 3, 4, and 5, like 60 minutes and 360 degrees. But no one has 60 fingers, so sometimes they compromised and used 12, which at least is divisible by 2, 3, and 4.

And that's why a foot is 12 inches, a pound is 12 ounces, and a day is 12 hours (a night is 12 hours, too).

OK, I hear you all saying, "But, no one has 12 fingers!" Next question!

OK, I hear you all saying, "But, a pound is 16 ounces, not 12! What's up with that?" Ah, good question!

The Roman Empire had contracts to pay soldiers, etc, in ounces of silver, gold, etc. And the Empire was running out of money. So, they redefined the ounce to make it smaller. They made it a 13th, then a 14th, etc, until it hit a 16th of a pound, and then the Empire fell. Since the Empire wasn't paying anyone in inches of anything, the inch stayed 1/12th of a foot.

How's that for the mists of time! I bet the metric system doesn't have any cool stories like that!

Note: I might be making this up.

Actually, there is a lot of merit to this system. The French used a similar system of inches and lines. Each inch was divided into 12 lines. It's sort of like the metric system, but better. While metric can be easily divided by 2, 5 and 10, the old French system of inches and lines could be easily divided by 2, 3, 4, 6, 8, 9, 10 and 12. It's like the best of the Imperial system and the best of the metric system all rolled into one. I don't know why the system was ever abandoned. It seems so much easier.