Used Metric for the first time on project

[nickao]

I work in mils and any machinist can tell you the benefits of it better than I.

Initially a mil or thousandth of an inch was believed to be the smallest measurement a machinist or human could see(actually 1 arc minute(1/60 of one degree) is the smallest a human can generally differentiate) now a mil is stated as the smallest measurement a human can see and reasonably work with. Anything smaller a human really can not see. For a machinist it is a better measurement than a nanometer, which is way to small to work with, other wise we are in decimals of millimeters, which is a huge hassle compared to using mils. So working in thousandths of an inch is the best way to work for machinist tolerances, which of course in woodworking is probably overkill.

Still, I use thousandths of an inch to set up my tools and measure my router bits so I can get accurate offsets. If you do a lot of inlay and start working in mils or thousandths of an inch you will see the benefit and never go back for super accurate work.

One mil is .0254 millimeters, you can see the hassle that can come up working with such decimal numbers(whether in metric or not) in metal work where parts need to match up precisely. Saying 3mils or even  or 3.52 mils is a pretty simple nomenclature for a very small, precise number.

 

[PaulMarcel]

I'm sure the biggest challenge would be saying "Let's go grab 5 deciliters" instead of "Let's go grab a pint".

 

[tallgrass]

do not worry, the standard is the inch.,,,, the metric system was adjusted to give an accurate conversion, it was not always so.
when you are using metric still using standard, inch based mm...: )' it is like vhs( metric) vs beta (standard). vhs won. I use both, I am an ME and don't really care, i use both. i think the driving force was more post WW2 politics. my biggest problem is the inability of a ten base system's inability to handle real world geometry.

 

[tbellemare]

the inability of a ten base system's inability to handle real world geometry

Fractal math' supports your assertion...

Tom

 

[jonny round boy]

my biggest problem is the inability of a ten base system's inability to handle real world geometry.

Could you explain this further? I don't understand the issue.

 

[jvsteenb]

and I think the Euro was based on the value of a Guilder

Having been a part of the ICT team that was supposed to smoothen the transition from guilders to euro's in the municipality of Arnhem AND having the conversion rate ( 1 euro = 2.20371 guilders ) branded forever in my brain, I seriously doubt that....

do not worry, the standard is the inch.The metric system was adjusted to give an accurate conversion, it was not always so.

I'm afraid that is incorrect. The meter was in fact, derived from natural constants  -  actually the length of a pendulum that had a swing constant of 1s. Since then it was mainly altered to be more precise.
The latest physical definition of the standard was in 1889 and since then, the definition was only changed to enable more precision in the definition.
In 1959, the inch ( which was untill then diversified among the USA and the commonwealth ) was unified to the Canadian inch, which was in turn based on a metric definition, nl. 25.4 mm.
So in fact, your beloved inch is based on the metric meter, and not the other way around.

I'm sure the biggest challenge would be saying "Let's go grab 5 deciliters" instead of "Let's go grab a pint"

Yes, that was a tough one. We sort-of managed to get around it by saying: "Let's go grab a beer".... [cool]

Regards,

Job

 

[AlexThePalex]

do not worry, the standard is the inch.,,,,

Where? You mean the 3 countries of the 195 in the world that still use imperial?

the metric system was adjusted to give an accurate conversion, it was not always so.

Conversion? From what? You sound like you have an insight in these matters most of us don't have, but what do you mean precisely?

when you are using metric still using standard, inch based mm...: )'

Again I have to ask, what does this mean? Inch based mm?

it is like vhs( metric) vs beta (standard). vhs won.

I disagree. VHS an Betamax where two ways of implementing a new form of technology.  Betamax, the superior system lost because it's inventor Philips made a proprietary system of it and didn't want their name be associated with dirty pictures. So all people who wanted to see dirty pictures now bought VHS, boosting their sales.

The imperial system was developed over many thousands of years, because of the need for people to measure distances. Because people didn't really know how to do it properly, they tried a couple of the first things that came to mind, like comparing it with their own body parts. That's how we got distances like the foot, the el (hand to elbow), the step, and the thumb (inch). Cultures before the Romans already did this, and that's what developed eventually into the imperial system. Considering how people all are sized differently, and so are their body parts, you can see how subjective and imprecise this system was.

So there came some clever Frenchy, Napoleon, and he thought this should be done better. Instead of using subjective measures he tried to introduce a measuring system that could be objectively measured, actually involving actual SCIENCE to measure something instead of putting our evolved monkey paw next to it. And so the meter was born by defining it as the distance of a certain metal bar of a certain metal that was to be kept under a set temperature, air pressure and humidity. Then the decimeter, centimeter and millimeter where derived from that piece of metal by dividing it over and over into 10 equal parts.

Instead of just 'everybody' making up their own subjective measurements by using their differently sized hands, thumbs and feet, now there was one objective standard object to fall back to. This standard has been refined over time, first by using a better type of metal and more precisely controlled atmospheric circumstances, later by defining it with the use of radio waves, then X-ray waves, and the currently accepted way used by the scientific community as the distance traveled by a photon in a vacuum in a certain amount of time.
       
So it is a matter of evolution. Instead of a inaccurate trial an error system that developed all over the world it was consciously developed where we actually started to use our brain as the ultimate body part, instead of our feet and thumbs.

And let's not forget the current precision of the imperial system was developed after imperial scientist saw how good the metric system really worked. After the metric system was developed by the French the imperial scientist finally realised how subjective their system was and started to look for ways to define the imperial system to the exact same objectivity and precision the metric system had. Unfortunately they never realised that it was easier to work with factors of 10 instead of 12. And even if they did, their national pride stood in the way.

The difference between the imperial and the metric system is not, as described above, a mere difference between VHS and Beta, it is the difference between riding a horse and driving a car, between a mud cabin and a skyscraper, between a $45 Chinese saw from a big box store and a Festool TS55.  

my biggest problem is the inability of a ten base system's inability to handle real world geometry.

As already requested by somebody else, please explain this remarkable statement you make here.

 

[AlexThePalex]

I work in mils and any machinist can tell you the benefits of it better than I.

Initially a mil or thousandth of an inch was believed to be the smallest measurement a machinist or human could see(actually 1 arc minute(1/60 of one degree) is the smallest a human can generally differentiate) now a mil is stated as the smallest measurement a human can see and reasonably work with. Anything smaller a human really can not see. For a machinist it is a better measurement than a nanometer, which is way to small to work with, other wise we are in decimals of millimeters, which is a huge hassle compared to using mils. So working in thousandths of an inch is the best way to work for machinist tolerances, which of course in woodworking is probably overkill.

Still, I use thousandths of an inch to set up my tools and measure my router bits so I can get accurate offsets. If you do a lot of inlay and start working in mils or thousandths of an inch you will see the benefit and never go back for super accurate work.

One mil is .0254 millimeters, you can see the hassle that can come up working with such decimal numbers(whether in metric or not) in metal work where parts need to match up precisely. Saying 3mils or even  or 3.52 mils is a pretty simple nomenclature for a very small, precise number.

This entire post shows how little you grasp of the metric system and machining. You always like to express your opinion vocally nickao, sometimes sounding like you declare an absolute truth but this time you're far off. I hope you don'tmind me saying this, but in Holland we have a saying that I think applies, 'what the peasant doesn't know, he doesn't like to eat'.

Let me explain.

Initially a mil or thousandth of an inch was believed to be the smallest measurement a machinist or human could see(actually 1 arc minute(1/60 of one degree) is the smallest a human can generally differentiate) now a mil is stated as the smallest measurement a human can see and reasonably work with.

It doesn't matter what a machinist can see. Machining is not done on the eye. It is done with machines. Machines that are very exact because you need a high precision. Because of this a high precision is built into every machine used for machining, and into the measuring tools the machinist uses. It is actually required to use this precision, and a machinist who merely uses his sight wouldn't get much work besides building a cart for his 8 year old son.

For a machinist it is a better measurement than a nanometer, which is way to small to work with, other wise we are in decimals of millimeters, which is a huge hassle compared to using mils. So working in thousandths of an inch is the best way to work for machinist tolerances, which of course in woodworking is probably overkill.

One step at the time please. You go here from millimeter to nanometer and forget about the micrometer between it. The correct order is:

Meter
millimeter (1x10^-3) or a thousandth meter
micrometer (1x10^-6) or a millionth meter
nanometer (1x10^-9) or a billionth meter
etc
etc
....

Machinists in metric countries use the micrometer as the most used unit to measure required tolerances. The millimeter is too big and the nanometer too small, except for special applications that require an even higher precision. You can only measure micrometers with specialised equipment and not by the eye.

You say a mil is a thousand of an inch. One inch is still 25,4 times bigger than a millimeter, so one mil is still 25,4 times bigger than a micrometer. Since engineers can measure with micrometers very exactly and easily, the micrometer offers 25,4 times the precision of the mil.

One mil is .0254 millimeters, you can see the hassle that can come up working with such decimal numbers(whether in metric or not) in metal work where parts need to match up precisely. Saying 3mils or even  or 3.52 mils is a pretty simple nomenclature for a very small, precise number.

I don't understand why saying 3.52 would be easier than saying .0254 just because the later is one syllable longer. But to be honest, the engineer/machinist doesn't say 0.254 millimeter, he would just go one step down the ladder and say 254 micrometers. If your logic applies 254 would be easier again to say than 3.52.

So in short I'd say that you might be heavily opposed to the metric system because you don't fully understand it. On the other hand I realise that is is difficult to switch over to a new system especially if it's not widely used in your area. And it's true you probably won't need it in your lifetime, so you can go on as you're used to without any problems. But woodworkers might not need it, but a lot engineers and the scientific community already use it exclusively. And as always, when the higher educated people in a country, who are often the leaders, adopt something, then eventually the rest will follow suit. 

 

[image132]

Wow Alex...

 

[Wim]

This is a very interesting subject to me.
When I started my technical education in Holland in the late 50's, we had to learn the metric and the imperial system. In daily life then (in Holland) you shopped in kg and liters, but the industry used more imperial than metric because of the overdose in English and American machinery and material. And a lot of people hated "made in Germany (= metric)" because of WW2. Slowly this changed and now (to most Dutch) imperial units are something from Ruritania (except for regular visitors of the UK or the USA).
What is best is what works best for yourself. I have used metrics all my life but I'm able to do imperial calculations. And I think calculations in metrics are much easier and less error prone. Ask the English how it went with the "metric" pounds when they got rid of the shillings. And is working with metric dollars difficult?
In the old days most market squares had their local measurements carved in stone. Every market vendor had to copy his measuring sticks from it. I found such a stone in Italy.

 

[tbellemare]

It's interesting that you should talk about US or English machines. I think the only reason that a worldwide standard hasn't been adopted for many different things is because businesses in various countries have a lot of control over their respective governments.

As and example, the automobile was invented in Germany and I suspect the the U.S. has more roads than anyone else in the world. Both countries put the driver on the left and the car on the right. The former island empire a few kilometers away decided to do it backward and the only reason I can think of is so that their people and colonies would buy cars from them.

I've driven on the right side sitting on the left - here and in Europe. I've driven on the left side sitting on the right - in England. I've even driven on the left side sitting on the left - in the U.S. Virgin Islands (yes, it's a little bizarre). I don't see any advantage of either of the first two so why are they different? I suspect to promote commerce of a specialized type.

Why does that same former empire have to have electrical outlets and plugs that are different from everyone else?

I really think the reason the U.S. hasn't gone Metric is a perceived advantage for commerce. Notice I said "perceived".

Tom

 

[cje]

As and example, the automobile was invented in Germany and I suspect the the U.S. has more roads than anyone else in the world. Both countries put the driver on the left and the car on the right. The former island empire a few kilometers away decided to do it backward and the only reason I can think of is so that their people and colonies would buy cars from them.

I've driven on the right side sitting on the left - here and in Europe. I've driven on the left side sitting on the right - in England. I've even driven on the left side sitting on the left - in the U.S. Virgin Islands (yes, it's a little bizarre). I don't see any advantage of either of the first two so why are they different? I suspect to promote commerce of a specialized type.

I think referring here is better than copying: Wikipedia has an interesting article.

Best, CJ'60

 

[woodguy7]

Alex, how much of a geek are you  [poke]

I always learn stuff on here, especially when Alex is on 

 

[VictorL]

I'm sure the biggest challenge would be saying "Let's go grab 5 deciliters" instead of "Let's go grab a pint".

Nope. Wrong answer.  
The best answers are "Let's go grab medium bottle". Or glass of beer.    The right answers are "Let's go grab half of liter" or "Let's go grab 500 grams"  You still can tell "Let's go grab 500 milliliters"  or "Let's go grab 5 deciliters" but beauty of metric system that you always have the same base.  It is still five something.  I hate to convert cubic feet to gallons. Square inches to square feet or yards. Too much math.
My height is 1m76cm this is 1.76 m or 176 cm, or 1760 mm, or 0.00176 kilometers. Magic number is 176. But when I switch to imperial it is 5'10" or 70" or one yard, 2 feet and 10 inches, or 5 5/6 of feet. But what's my height in miles? Why I can't measure myself in yards only?   Where is convenience of Imperial units?  

Regards,
VictorL

 

[AlexThePalex]

.... but beauty of metric system that you always have the same base.  It is still five something.  

I hate to convert cubic feet to gallons. Square inches to square feet or yards. Too much math.

My height is 1m76cm this is 1.76 m or 176 cm, or 1760 mm, or 0.00176 kilometers. Magic number is 176.

But when I switch to imperial it is 5'10" or 70" or one yard, 2 feet and 10 inches, or 5 5/6 of feet.

But what's my height in miles? Why I can't measure myself in yards only?  

This . Demonstrates . It . All .

Good post.

 

[tallgrass]

alex-
sorry for my late response.
This is interesting. I just got back from Boeing, where i showed the head of the machining facilities. your post. head scratching insued?
Here is the problem. If i understand what you are saying about a unified inch is correct there would need to be a change in the standard therefore requirering a conversion factor for standard plans before the date of unification? I am not sure this is the case. but i am looking.He showed me their standards going back to the 30's Very cool by the way. there was no change in the standards. there was in the metric standards. on the pet peeve area i find it funny the kilo is not static. there are problems when your standard fluctuates do to mass wasting.

As for the geometry issue. the best example is break an object into three equal pieces. this is something you can do using calipers ect. you can then express the pieces in terms of a ratio or fraction in what ever units you want. If you have  ten foot pole you can not cut it into 3 equal pieces. So if you take 3 pieces exactly 3,1/3 so that they add up to 10 feet. you could not create  those pieces in the metric system. Just on example

i am going to call NIST  and ask for the what the change was.I am really hoping the call me an idiot and hang up on me. The reason i question this is not that you are wrong but i have dealt  lt with pre WW2 plans and there was no conversion required for modern continuity. As for the changes to the mill....I say this in a flip kind of way....but when looking at the change to 25.4 the inch did not change. as a matter fact this lack of direct conversion causes problems in dealing with old metric plans.

I use both all the time i just find it interesting the politics and idea that the metric system is "better" in some ways it is easier but in other ways a pain.

 

[tallgrass]

i will say if i am able to work in whole mm than it is great. though i do find the mm course and working in micro meters is just a joke. i always chuckle when i see 4.4mm or anything like that. kind of dumb. the whole being no fractions [big grin] [big grin] [big grin] [big grin] [big grin]

 

[VictorL]

As for the geometry issue. the best example is break an object into three equal pieces. this is something you can do using calipers ect. you can then express the pieces in terms of a ratio or fraction in what ever units you want. If you have  ten foot pole you can not cut it into 3 equal pieces. So if you take 3 pieces exactly 3,1/3 so that they add up to 10 feet. you could not create  those pieces in the metric system. Just on example

Hmmm.  I can cut almost any pole into 3 equal pieces (assume pole is between 1" to 300')
10' = 120" or 3048mm, then cut into 3 equal pieces you'll get 1016mm
Most likely this pole will be 3000 mm (Like FS/2 -3000 rail) or 3050 mm, because these numbers are round, and easier to understand.  Problems arise when use two systems simultaneously. In aviation that's material thickness. In imperial that's 1/32, 1/16, 1/8, 3/16 etc. There is no exact metric equivalent, metric base industry is using different grid 0.5mm, 1.0mm, 1.5mm, 2.0mm etc.  You can order 1.1mm, 1.2mm, 1.25 thick material, but how often you are ordering 3/128 thick aluminum?

VictorL

 

[Michael Kellough]

The dividing a stick into thirds example is persuasive in on paper but in practice  you have to account for the kerfs and then you're back to needing a system that allows for easy discrimination of small distances and I think metric wins.

I've just made a new fence for a large cutting table. I used a combination imperial/metric scale and added vernier cursers to get finer results using simple line matching. On the imperial side the finest I can go in a (comprehensible way) is 1/64" (.015625") but on the metric side I can get down to 1/10th mm (.00397, four times finer) without head or eye strain.

 

[jvsteenb]

alex-
sorry for my late response.

Hi tallgrass,

I'm assuming you're actually answering me - not Alex.
About the conversion from the diversified to the unified inch:  There's little need.
In fact the "old" inch is still used for survey purposes ( solely in the USA ) and is now sometimes referred to as the "survey inch".
I must confess I have been responsible for the technical architecture of the GIS software systems used at the municipality of Arnhem, so measurement and coordinate systems have been a big part of my professional life for quite a couple of years.
The old inch ( nowadays the "survey inch" ) is rather close to the unified inch - it's 25.4000508001016002032-and-then-some  mm's . For surveying purposes, this difference is actually significant, as it can translate to rather imprecise locations when used over distances of 100's of miles or more. For machining purposes, this is more or less irrelevant. Pre WW2, there was no way a plane manufacturer could manufacture parts within such close tolerances - it's only 2 ppm or 0.000002 %, and temperature variations of even a single degree can make parts swing in size multitudes of that amount. So in fact, it would have been useless to "recalculate" the measurements.

I'm very interested in your findings when dealing with the NIST - please keep us informed.

Regards,

Job

BTW: Although the metric systems seems way more logical to me, I believe in using what you're comfortable with. If your brain does fractions easier than shoving decimal points, by all means use imperial. Just don't expect the rest of the world to follow your "logic".