Used Metric for the first time on project

[tallgrass]

I love these conversations.
The example i gave about the three unit is just an example of the 3.3333333333.. example. Kerf is not part of it. if i asked you to give me three pieces that added up to 10 feet or ten meter you would run into the .333333333333 issue. This is just one example. IT has more to do with being stuck with the ten base system and not the definition of the unit in question.I guess what i like about the standard system is that if i want to use a 10 inch foot rule, fractions,decimals what ever.I have the choice. i can make a unit that scales or fits the situation rather that make one work for all cases. If your making a lay out of bolt hole around a circle you will be using a compass and the correct procedure to locate them and it will not be a ten base answer,  . Every time you use story poles or sticks you are not using the metric system you are using your system. O, by the way your telling time in standard '

Being a ME i love the simplicity of a ten base system in calculation, and using the metric system is great for that.this i love do not get me wrong. When i am in the machining lab it is amazing to watch our machinists do their insane accuracy work. Sodium lamps and wave lengths blah blah, temp controlled metrix. It makes me drool.

I find my job is easy, the machinists have the hard job.I find that i am unable to describe how they do their work. From my calculations down it works fine but from the machine floor to my desk it seem very clumsy(metric system)

Just out of curiosity have you ever wondered about the kilo. Its mass fluctuates due to mass wasting ect. If the prime example in Frances is not constant due the basic physics than how can it be a constant? Meaning that the references that are based on the prime unit can not be the same.

O, NIST is getting back to me....I could hear their heads hitting the table when i asked. Anaheim eh, I am at JPL. So we have a past of metric vs standard arguments all the time IT is fun.I love playing with the guys from ESA. To piss of one of Thier guys i gave him a drawing in cubits, as a joke.
This is type of conversation should take place in a coffee shop.

 

[tallgrass]

OOOPS you are in Europe not S.California. I miss read your location. [embarassed]

 

[GPowers]

WOW!  [eek]

This has gotten in too quite the academic discussion. I was just excited about using the Metric system for 100% of this small project.  Intresting to see some many different opinion on the Metric vs Imperial systems.

 

[tallgrass]

i love you metric moment. did you find the mm to course or did you use it as your smallest unit, did you round or down? good job by the way. [big grin]

 

[GPowers]

i love you metric moment. did you find the mm to course or did you use it as your smallest unit, did you round or down? good job by the way. [big grin]

Since this was a SYSport carcass I used MM as the smallest unit. Made things simple.

 

[tallgrass]

that's great

 

[ossietim]

Now if we could all agree on Power  [big grin](ie 110v versus240v) then that would be better.Don't you think?

 

[tallgrass]

yup

 

[jvsteenb]

Just out of curiosity have you ever wondered about the kilo.

Yep - that's a bit of a problem. Until now, nobody has come up with a neat definition based on physical constants.
Actually, the 1799 definition was neater, from a technical perspective: the mass of 1000cc's of water at 4 degrees celsius ( at that temperature water has it's highest volumetric mass ) .
Sadly, when they had just determined that this definition was a good one, they chose to fabricate a "standard" and declare that leading. Not the SI's finest hour.
Then again, a definition based on physical constants may not be as constant as we like it, for some of these constants might vary with the expansion of the universe.... [unsure]

Regards,

Job

 

[tallgrass]

yea,,,,well my brain is not going to think about expanding universe, i can't keep track of my expanding hot air hot air. yea the kilo seems like a stub toe.

 

[Wim]

I have the impression that it is not really imperial vs metric but decimal vs fractional. If somebody is working with decimal inches, the calculations are the same as with the metric units. Only the base unit is different. And in the metric system we use more steps between the meter and the millimeter, being decimeter and centimeter.
And every engineer should know that the argument of cutting a pole in three and when put together will not give the same length again is a theoretical trick. Because of the way you round 1/3 give you differences in length. A dimension in the field of engineering is not possible without its tolerances.
My education started with instrument making and I ended my professional career in shipbuilding. I learned to work with 0.001 mm and ended up in an industry where a few mm wrong was not much of a problem. In woodworking my habits are still alive and I try to work with 0.1 mm. But then reality kicks in and I work with 0.5 mm and wiggle my pencil a little around the marks on the tape ruler.

 

[jmbfestool]

Just got done building a carcass for a Sysport and use all metric dimensions for its construction. I could not believe how much easer it was to use metric over imperial measurements.  I never realized how frustrating and inaccurate Imperial measurements are. It was much easer and quicker to do all measurements in just millimeters. No fractions, on inches vs Feet etc. Just how many millimeters something is.

So for me it is good by to fractions, no more 3/16th or 7/8th or 3/4 of an inch for me, I'am a metric convert.

Now I wish the rest of the United states would finish, the conversion to Metric, they started back some thirty years ago.

We have only managed half the job in the Uk petrol in litres distance in feet or yards or miles dual tape measures pints of beer  im sur there are more examples but I cant think of them [scratch chin]

Thats normal for England we only ever do things by half never fallow them through.  I was brought up in Holland and they only use Metric so when i came back to England I thought WTF?!?! why they using Metric and Imperial. I thought Imperial is rubbish so never used it couldnt be bothered. Till I started doing joinery the joiner I worked with used Imperial and Metric so I had to use Imperial and Metric and thats how I carried on doing.

I use both Imperial and Metric depends what comes closest when measuring. But unless its a easy number to divide or times I will use imperial like i said it came to a easy number but most the time I use Metric like  said above its sooooooo much easier to do maths with metric

 

[jmbfestool]

metrication would not be that hard to do really,.... expensive, but not hard. Seems to me that many/most Americans have a good general idea of the metric system. Mostly from osmosis. We generally don't give it a thought, because there is no incentive to care.

Most of the products we buy are labelled in both...... remove the imperial and it is done. Highway signage would be expensive, but since this country is looking for job programs, there you go. I am sure there is someone out there that can change mile markers to Km markers. It's not like it need to all get done at once. And when they get up to the North-east corridor they can renumber the exits to something that makes more sense then sequential!

well we are still on the mph in uk

YEah.  I went to meet my old mates in Holland and Drove my car so I could drive around places showing my girlfriend where I lived and stuff. BUT I kept speeding because I forgot the signs where in Km so when it said 50kph I would travel 50mph with my car so doing 80kph oops!!! When it said a hundered 100kph I did click a lot sooner because I kept on thinking their isnt a speed limit at a 100mph lol.

 

[jmbfestool]

   As an Englishman living in France I have been converted to metric whether I like it or not.Well I like it!Nowadays anyone speaks in feet and inches I don't want to know.As the OP says metric is so much more accurate and simpler.Not only that but it's logical.Where's the logic in 12 inches to foot?Or 1760[I think]yards to a mile?

As I jokingly mentioned in the tape measure thread the logic behind the 12 inches is it can be even divided by three and four where the standard of ten in the metric system can not.

Thats what I mean! What brice is saying sometimes Imperial is a easier number to use for certain things. That 12 inch is a good example. That's why I use both Imperial and Metric.

 

[jmbfestool]

i one of many in the uk that still goes to a merchants and asks " can i have 10no  4x2 3.6m long

Yeah thats funny. Never really thought about it when saying it. I also say it like that.  The thing is if your asking for 10no  2x1(Imperial) at 3.6(metric) planned

It actually comes  at 45x22(metric) at 3x6(metric) 

 

[jmbfestool]

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. 

IMPRESSED!

 

[tallgrass]

I am an ME (mechanical engineer)and you are right about tolerances, i was not meaning to imply that they did not exist.Being that i do R&D at JPL, i deal with ESA all the time. We argue all the time about this, great fun, youtube has nothing on us.thank god for no movie cameras.

i see the machinists doing lay ups using references and layout calibers all the time. they add up known certified references, whether sign bars or stacking 1-2-3-blocks. that is why a used the adding of three blocks ect, (yes the blocks are to a tolerance)not a trick. the neatest thing i have seen them do is the frequency of a known gauge wire at a know tension and measuring the frequency, giving the length if the wire. I really wish i could take pics of how they do their stuff.  my "trick"was just a simple and brief example,
in my opinion you are right about the real difference is not units but in decimal vs fraction. I mentioned that earlier. the difference is also choice, if i use the standard system i can choose what ever; decimal, fractions i want but in the metric i have to do it only one way.

So you made instruments?What kind?What did you make? sounds interesting.

 

[tallgrass]

so what do you do when you need something finer than the mm? I use metric all the time but i find it sometimes too course. I am talking regular rules not specialist stuff.I have rulers that do to 64ths i do not have any that 10ths of a mm. I just walked into my shop to check, so how do you guys do it? i am talking about wood working stuff. for the metal working i do i have it covered.

 

[Nigel]

  As an Englishman living in France I have been converted to metric whether I like it or not.Well I like it!Nowadays anyone speaks in feet and inches I don't want to know.As the OP says metric is so much more accurate and simpler.Not only that but it's logical.Where's the logic in 12 inches to foot?Or 1760[I think]yards to a mile?

As I jokingly mentioned in the tape measure thread the logic behind the 12 inches is it can be even divided by three and four where the standard of ten in the metric system can not.

Thats what I mean! What brice is saying sometimes Imperial is a easier number to use for certain things. That 12 inch is a good example. That's why I use both Imperial and Metric.

    Mmmmm ok then what about 112 pounds to a hundredweight?Or 14 pounds to stone?Or 16 ounces to pound?Or 8 pints to a gallon?And what's an American gallon??????

 

[Knock on Wood]

 Mmmmm ok then what about 112 pounds to a hundredweight?Or 14 pounds to stone?Or 16 ounces to pound?Or 8 pints to a gallon?And what's an American gallon??????

Or how about this....

I once had a horse that was "16.5 hands" - a hand is measured as 4 inches - (52 inches) tall ....

.....and Noah's Ark was "300 Cubits" - length from the tip of the middle finger to the elbow ~ 17 to 22 inches ~ or (approx. 450 feet long).....

......could Noah have been the first person to unknowingly give people the middle finger?  [eek]

Jim