Electronic conventions I hate

Sceadwian said:

I've been personally trying to convert to Meter/C for years, it's just too ingrained what to expect.

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I know exactly how you feel. I was unlucky enough to be in the last year of children taught the imperial system in Australia.

I work in metres but think in feet and inches. I still think SI units are the way to go.

Another point is that with the metric system, you don't have to worry about combining fractions. i.e. 9/32" plus 1/2" plus 11/64. Yeah, you can do it, but it would take a lot longer than adding something simple like 10.4cm + 5.8cm +29.6 (the numbers are arbitrary). Much easier to do in your head, and would take much less time.

Kiss, I'm thinking original construction, not American construction. If I have a mismatch between studs where I don't think things are properly supported (Happened twice in the initial stages of remodeling my house) I won't go cheap and only support where there is a stud, english or metric, I'll dig out drywall notch the stud if required and put a beam for horizontal distribution to correct for the mismatch of centers.

If what I build falls down, it's my fault.

DerStrom8 said:

Another point is that with the metric system, you don't have to worry about combining fractions. i.e. 9/32" plus 1/2" plus 11/64. Yeah, you can do it, but it would take a lot longer than adding something simple like 10.4cm + 5.8cm +29.6 (the numbers are arbitrary). Much easier to do in your head, and would take much less time.

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But you can state inches in decimals too. You can even buy rulers that are graduated in 10th/100th inch, and precision instruments that give 1/1k and 1/10K inch.

BrownOut said:

But you can state inches in decimals too. You can even buy rulers that are graduated in 10th/100th inch, and precision instruments that give 1/1k and 1/10K inch.

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Yes, but inches in decimals is not standard, and can be difficult to "translate" to common lengths. For example, trying to translate 9/32 of an inch (0.28125") is would be difficult to find using a ruler. Otherwise a base ten imperial system would be just as good as the metric system. Speaking of which, does anyone know what the metric system is based on? We've already discussed the imperial system as being based on the length of the king's foot, etc. But who decided how long a meter would be, and why?
Just getting curious now

DerStrom8, look up the SI measurement system, that's what modern values are made from. The French are the creators of the original system; the SI system is considered standard for science. The primary goal of the modern SI system is to remove any semblance of artifact based measurement. This makes things difficult because in practice such systems are system dependent.

DerStrom8 said:

Yes, but inches in decimals is not standard, and can be difficult to "translate" to common lengths. For example, trying to translate 9/32 of an inch (0.28125") is would be difficult to find using a ruler. Otherwise a base ten imperial system would be just as good as the metric system.
Just getting curious now

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It is just as good. That some measurements are stated in fractions have nothing at all to do with using inches/pounds, etc. It's virtually unheard of to use fractions in engineering, even when dealing with imperial measurement systems.

DerStrom8 said:

We've already discussed the imperial system as being based on the length of the king's foot, etc. But who decided how long a meter would be, and why?

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"The base units used in the metric system must be realisable, ideally with reference to natural phenomena".

Originally meter was defined as a fraction of earths meridian-arc. Then there was the one meter prototype bar, but because a physical bar gets shorter over time, the definition is now based on speed of light in a vacuum (299,792,458 metres per second). One second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.

For kilogram, there is still a prototype kilogram that defines how much is one kilogram. That prototype is getting smaller over time too. Scientist still struggle to find better definition for a kilogram.

**broken link removed**

I copied this map from Wikipedia. It source is the U.S. Metric Association. The map is metrification by year. Black is the countries that aren't metric yet although there are reports that Liberia and Burma are in the process of adopting it.

All scientific units including volts and amperes are derived from the metric system.

Because the U.S. is part of NATO all their military equipment is designed using the metric system.

Why would you continue using makeshift methods to overcome the inherent difficulties in an outdated system?

I really do not understand it.

Come U.S., join the modern world.

hdc090360 said:

Why would you continue using makeshift methods to overcome the inherent difficulties in an outdated system?

I really do not understand it.

Come U.S., join the modern world.

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I agree completely

Before you place the US on the black list.
https://en.wikipedia.org/wiki/Metrication_in_the_United_States

As soon as you can determine a method to give 300 million people a masterful knowledge of a very basic system which they have had little to no exposure to since birth, you let me know and I'll be sure to recommend it being implemented here. It's not like we have a government which can simply declare that people must change, there is an overwhelming tendency to change to global norms though.

Sceadwian said:

Before you place the US on the black list.
https://en.wikipedia.org/wiki/Metrication_in_the_United_States

As soon as you can determine a method to give 300 million people a masterful knowledge of a very basic system which they have had little to no exposure to since birth, you let me know and I'll be sure to recommend it being implemented here. It's not like we have a government which can simply declare that people must change, there is an overwhelming tendency to change to global norms though.

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The government can't force people to change, but it can decide what schools teach children. IMHO they should start teaching more of the metric system and less of the imperial system in elementary school. After a couple of generations this country will have accustomed to metric and will make life a lot easier for a lot of people.

For those who don't understand the US system of weights and measures it is very simple:

Then down with every "metric" scheme

Taught by the foreign school,

We'll worship still our Father's God!

And keep our Father's "rule"!

A perfect inch, a perfect pint,

The Anglo's honest pound,

Shall hold their place upon the earth,

Till time's last trump shall sound

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Now all kidding aside if we go back and look at the US system of measurement you really don't have to go back very far. As far as being a country the US is a relatively new comer to the game. Figure we started this around 1776. Back then we had this really big argument with those who are now our neighbors and staunch allies across the big pond. We gained our independence from what was then our mother country.

Like any child who gains independence from a parent they disliked the child began to do everything possible to dissociate them self from the parent.Mattered not if the parent was right or wrong.

The child developed their own currency, a system of weights and measures and other things. It mattered not if the system made any sense at all, it worked well at the time. The child saw their system as an extension of their independence. That system enabled the child to place a man on the moon after Sputnik kicked the child's ass.

Being an engineering type with an analytical mindset I really do believe my mother could have baked the same wonderful apple and cherry pies she baked using metric weights and measures for the ingredients if her recipes were written that way. Alas, she used teaspoons, tablespoons of sugar and cups of flour. While I can see this clearly, my two sisters and one brother can't.

To me, the metric system of measurement makes more sense and is a simpler method. So go figure?

Just My Take
Ron

When it comes to cooking, and especially baking, that's a place where the imperial system is clearly superior. It is because measurements such as "cup" and "tablespoon" are very convenient when making, say a cake for a family member's birthday. How would metric be useful in that case?

Ie

How is 62.5ml simpler than 1 cup?

How is 1.3ml simpler than 1 tablespoon?

etc.

All our recipes have metric cups and tablespoons. The thing about metric units is that most are smaller than the imperial, making it easy to pick a metric unit close enough to the old imperial one. My metric tablespoon measurers are 20ml, metric cup is 250ml, all VERY easy to work with.

As for inches being as good as mm, I don't think that's right. Inches are just too big for most electronics stuff. Consider a PCB 96mm in width. You want to make it a tiny bit wider, so go to 98mm. If you want to increase by 10% it's 96*1.10 = 105.6mm. All logical.

The mm is small enough so you can round most things to a mm on your drawings and designs, with little penalty and no need for messy deciaml places or fractions. It's a REALLY nicely sized unit for most things we do in electronics.

But if your PCB is 3&3/4" wide and you want a bit more you do what? Go to 3&7/8"? 3&13/16"? That's just nasty. And don't even try an add an exact 10% increase.

Well, we have milli-inches (mills, for more technical types). For example, your circuit board can be 10 inches. To increas by 10%, we can to go 11"". Or if it's 1", we can go to 1.1" No problem at all. The only difference between the systems is the metric has special 'names' for 1/10, 1/100, etc. But we do the same thing with inches, just don't have fancy names. Doesn't change a thing.

We've used this system for 200 years, and I don't see where we've fallen behind in engineering in any way.

Sounds like brownout would be happy with a bastardised metric imperial system

BrownOut said:

Well, we have milli-inches (mills, for more technical types). For example, your circuit board can be 10 inches. To increas by 10%, we can to go 11"". Or if it's 1", we can go to 1.1" No problem at all. The only difference between the systems is the metric has special 'names' for 1/10, 1/100, etc. But we do the same thing with inches, just don't have fancy names. Doesn't change a thing.

We've used this system for 200 years, and I don't see where we've fallen behind in engineering in any way.

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-; the USA would have fallen back exporting cars to overseas countries if the manufacturers hadn't used metric bolts and screws.

PCB manufacturers use metric values to calculate the price for a board. Ordering a PCB of e.g. 2&3/16" your order would certainly be rejected.

The worst "tohuwabohu" applies to screw and drill dimensions. The only drill bit dimension used is the shaft diameter of carbide drill bits (PCB manufacturing) which is 1/8" (3.175mm) while the drill is based on metric dimensions, e.g. 0.6mm, which converted to inches will stop at 32 digits behind the decimal point. Even expressed in mils the value won't be even at an acceptable point of three digits after the decimal point.

Cups have a defined volume for imperial dimensions only.

An Italian Espresso cup has a volume of 10ccm, a Turkish coffee cup has a volume of 20ccm, a German coffee cup has a volume of 100ccm and a French coffee cup has the volume of a 1/2 cup size "B" bra. -;

Finally I guess different dimensions (metric or imperial) are preferably used where they have been learned in the first line. Designing PCBs I always switch grid size to metric using the equivalent value for inches e.g. 2.54mm (0.1"), 1.27mm (0.05") down to 0.079375mm (0.003125"). That way I can imagine the component positions (mental eye balling) easier on the final product.

Boncuk

Boncuk said:

Designing PCBs I always switch grid size to metric using the equivalent value for inches e.g. 2.54mm (0.1"), 1.27mm (0.05") down to 0.079375mm (0.003125"). That way I can imagine the component positions (mental eye balling) easier on the final product.

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I hate when half of the components are metric and half imperial (spacing of contacts). Especially with connectors. But I love Proteus because switching between imperial and metric grid is easy.

misterT said:

I hate when half of the components are metric and half imperial (spacing of contacts). Especially with connectors. But I love Proteus because switching between imperial and metric grid is easy.

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Well, there you go: if you have a good tool that can handle either measurement system, then what's your complaint about non-metric units? Do they really offend you that much?