Metric and customary measuring systems

[Ken S]

We have had discussions in the past about which system of measurement is preferred on the forum. I found this video fascinating, and hope you enjoy it.

https://youtu.be/yseldOMcT4Q

For the record, even though I live in the US and live in an area dominated by US Customary Measurement, the Tormek is a metric machine. My preference for Tormek related forum measurement is Metric. (Enough 304mm, actually ten onch, odd size grinding wheels!)

Ken

[Dutchman]

In the comments, by Mark Holm:
I am a quantitative scientist, analytical chemist.  I have been using the metric system for scientific work since ninth grade biology class in 1969.  As I learned how to make more complex measurements and computations, I realized how useful strict adherence to metric units is.  All of the derived metric units are related by the same constant, one.  For instance, 1 joule of energy = 1 newton of force acting over 1 meter of distance = 1 coulomb of charge passing through 1 volt of potential = 1 watt of power applied for 1 second of time = 1 pascal of pressure applied to one square meter of area through 1 meter of distance.

In my experience, Americans who complain most loudly about metric measurement are people who either rarely measure anything, or perhaps frequently measure things, but only use measurement in simple ways.  People who make more complex measurements, particularly when they have to make complex calculations with those measurements, greatly appreciate that very many metric units convert so easily.

This comment is really illuminating. Try to make such an expression with imperial units, 

[jeffs55]

304mm is not 10 inches but you knew that, didn't you Ken? Or was that a joke? It does not matter how much metric measurements flow one into another. If you are trained in imperial then that is what is easiest for you. I am one of those Americans who measures simply and in simple ways. Even then, I seldom get it right.

[Ken S]

Jeff....oops, yes, I do know that, at least most of the time. I was thinking about the King grinding wheels. Wootz and I both have one and both are 254mm in diameter. I am convinced that whoever placed the order for the wheels stipulated ten inches rather than 250mm.

Jeff and Dutchman, your two replies illustrate the versatility of the Tormek. A skilled sharpener can obtain sharp edges with little measurement and a lot of care. These edges generally more than exceed needs and expectations. A skilled sharpener who is also skilled in mathematics can push back the frontier, as your grinding angles booklet has done.

In the early years of my telephone career, we used the hundred point measuring system. The manual test boards had 100 volt batteries. A solid short close by would read one hundred on the test meter scale. The reading was usually stated in "Volts", such as a "forty volt short". The correct unit of measurement was Ohms, however, we all knew our system, and it had worked reasonably well for decades.

Eventually we started using more sophisticated test meters and computerized testing which used the accepted units of Volts, Ohms, and Amperes. I was an early convert, although many of my coworkers never made the change. More skilled use of measurement lowered the really key unit of measurement, "Climbs", the number of poles I had to climb to isolate and repair the trouble.

Like Jeff, I still use US Customary units of measurement most of the time. After sixty eight years, inches and feet are comfortable. Not better, just more comfortable for my limited use.

I do find myself using more Metric measurement. The Tormek is a Metric machine. I use metric units with both the kenjig (based on Dutchman's tables) and Wootzm' Knife Grinders applet.  I measure water and Anti Corrosion Compound in milliliters. BESS sharpness measurements are expressed in grams. There are a few new tricks in this old dog.

Ken

[John_B]

Overall I prefer the metric system for measurements. I do have a number of measuring instruments that are inches and they all use decimals. All my micrometers, dial indicators and other devices are all inch with decimal. I do have a newer digital display caliper that I use for metric measurements. This proves useful when using the calculator to set bar height. Where I do not like Imperial is when you have drills that are in fractions necessitating a conversion chart on the wall.

[Dutchman]

Once you are used to the metric system, it is also easy to explain that a kilogram of lead weighs more than a kilogram of polystyrene foam. 

[Thymen]

I recently learned that the US actually uses the metric system. Which means, weights are related to the standard kilogram, distance to the standard meter etc. So there is no standardized pound or inch available, such as the standard meter or kilogram stored in the vaults of the body governing the SI units.

There are conversion factors, to convert these standardized units to US customary units. That's all...

Americans are metric, they just don't know it....

[Ken S]

The early US press cameras did not have built in range finders. The photographer would focus on three points with the groundglass. He would scribe three knife lines on his camera bed, "here, there, and yonder". We didn't need no metrics! 
(Actually, this primitive system worked reasonably well.)

Ken

[cbwx34]

Once you are used to the metric system, it is also easy to explain that a kilogram of lead weighs more than a kilogram of polystyrene foam. 

The kilogram is dead. 

[RichColvin]

Once you are used to the metric system, it is also easy to explain that a kilogram of lead weighs more than a kilogram of polystyrene foam. 

The kilogram is dead. 

Kierkegaard?

[Ken S]

Søren Kierkegaard was Danish. The Tormek is Swedish.

Ken

[Dutchman]

I recently learned that the US actually uses the metric system. Which means, weights are related to the standard kilogram, distance to the standard meter etc. So there is no standardized pound or inch available, such as the standard meter or kilogram stored in the vaults of the body governing the SI units.

There are conversion factors, to convert these standardized units to US customary units. That's all...

Americans are metric, they just don't know it....

You completely missed the point AND you made an essential mistake.

The metric system is characterised by the lack, in most cases, of conversion factors. I challenge you to convert the given example

1 joule of energy = 1 newton of force acting over 1 meter of distance = 1 coulomb of charge passing through 1 volt of potential = 1 watt of power applied for 1 second of time = 1 pascal of pressure applied to one square meter of area through 1 meter of distance.

into imperial units.

I am very sure that you do not know all the necessary conversion factors and you have to look up at least a few. Students are bothered with that kind of nonsense because their teachers have no idea of metric units.
This also leads to essential mistakes such as your comment:

... weights are related to the standard kilogram ...

My statement "it is also easy to explain that a kilogram of lead weighs more than a kilogram of polystyrene foam" should have already triggered you that kilogram is not a measure of weight.

Weight is a force and the unit of force is the Newton.
However, with the imperial units, the pound is used for mass AND for weight, so that students do not become aware of the distinction.

A kilogram of lead weighs about 9.8 Newtons here on the ground in the air, while a kilogram of polystyrene foam weighs about 9.2 Newtons as a result of the larger upward pressure of the atmosphere on the larger volume of the foam.

[Ken S]

When I was a teenager, I had no plans for an engineering or scientific career. Consequently, I had very few math or science classes. That youthful foolishness has been a constraint throughout my adult life. In hindsight, I regret not having that background. I am grateful that we have members who are very competent in these areas.

What really disturbs me is that my grandchildren do not seem on the path of mastering these disciplines.

Ken

[cbwx34]

...
I challenge you to convert the given example

1 joule of energy = 1 newton of force acting over 1 meter of distance = 1 coulomb of charge passing through 1 volt of potential = 1 watt of power applied for 1 second of time = 1 pascal of pressure applied to one square meter of area through 1 meter of distance.

into imperial units.
...

Bonus points if you use the FFF System.

...
What really disturbs me is that my grandchildren do not seem on the path of mastering these disciplines.
...

"OK Google" (or "Hey Siri").... How high do I need to set the USB to sharpen a knife at 20°? 

[Twisted Trees]

In the UK we are quite used to mixing Imperial and Metric, it is normal to by 3m of 2"x 4", Sheet material is 19mm x 8'x4' As cutting machines get replaced we are starting to get fully metric which is a slightly painful process.

I was surprised to buy a plank of Cherry that came from the USA which was 10' of 195mm x 38mm though 

My biggest issue is with tools, hate AF hex keys they are just fractionally different, but perfect for rounding things off... and don't get me started on cross head screwdrivers! there are at least 3 different types that at a glance look the same, but are just different enough to break something

Time for a global reboot, every mind and every machine set to the same measurements