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Metric vs. S.A.E.

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Blog entry by richgreer posted 01-10-2010 04:56 PM 2109 reads 0 times favorited 23 comments Add to Favorites Watch

I’ve lived in a 2 measurement system world my entire life. I’m seeing a very slow transition to the metric system but it is very slow progress and we in the woodworking world may be one of the slowest segments to transition.

Every once in a while we pay a price for the confusion that comes from having 2 measurement systems. The shaft that supports the tool rest on my lathe looks like it is 1 inch in diameter. I wanted a different style tool rest and I ordered one with a 1 inch shaft. When I went to install it, I discovered that the hole is actually a 25 mm hole. 1 inch and 25 mm are very close, but you cannot put a 1 inch shaft in a 25 mm hole.

I really wish we could get beyond this 2 measurement system someday. I doubt that I will see it in my lifetime.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.



23 comments so far

View jerryz's profile

jerryz

164 posts in 2000 days


#1 posted 01-10-2010 05:58 PM

I was brought up with the metric system and even when I went to attend college in the UK, they metrified so my exposure to the “Imperial” system is very recent when I came to the US.

Let me say however that I have come to appreciate the benefits of this system especially with regards to woodworking. I rebuilt my kitchen and really learnt to like it. It is so much easier to remember a fraction rather than a bunch of decimal numbers and it is also easier to make calculations. Soo now I am actually happier using it rather than the cumbersome metric system… But thats just me hi hi.

By the way when we say imperial system and we think that the british were the developers we are very much mistaken, the system is way older than that it goes back to the Greeks, the Romans and perhaps even before them.
It is very interesting that the foot length even though it’s name lends one to believe its measure was deduced from the human body was actually derived by calculating the circumference of the earth and it is in fact a fraction of it.

Think of that, 4000 years ago humans had calculated that the earth was in fact round and knew its Diameter.
We even know more or less were the lenght was first calculated or actually at which longitude (37 Deg)
How much knowledge has had to be re-discovered.

Later one the foot lenght was bartardized and made to fit political wims and the ensuing standarization mess that followed helped the birth of a totally new system deemed “better” (the metric system)

By the way anybody knew that this system was brute force rammed down in Europe by the French and none other than Napoleon Bonaparte??

View CaptainSkully's profile

CaptainSkully

1191 posts in 2280 days


#2 posted 01-10-2010 06:02 PM

I specifically used the metric plans for the burr puzzles I just made because I felt it would be more accurate. I even doubled all the dimensions. A fellow LJ made some burr puzzles, and he had to use all kinds of fractions. As a mechanical engineer , I’m very used to the metric system, which I prefer.

2 cups = 1 pint
2 pints = 1 quart
4 quarts = 1 gallon
12 inches = 1 foot
5280 feet = 1 mile

Where did they get all this stuff?

100 centimeters = 1 meter
1000 meters = 1 kilometer
1000 cubic centimeters (milliliters) = 1 liter

Now that makes sense… It makes the math a whole lot easier too. Multiply and divide by 10. My $0.02. At least our currency is in metric.

-- You can't control the wind, but you can trim your sails

View Brad_Nailor's profile

Brad_Nailor

2531 posts in 2679 days


#3 posted 01-10-2010 06:13 PM

The metric system is the tool of the devil…

I guess it’s whatever your used to using. I was brought up using the imperial system. Yes its not as conveniently set up as multiples of 10, so you can just add or subtract zeros, but I find the metric system confusing and cumbersome. If you have trouble adding and subtracting fractions do like I did and buy a calculator that does just that. Very rarely do I find myself having to convert pints into quarts when I am working on a woodworking project. I know all you mechanical engineers like the decimal system, and I was forced to use it when I worked in a cabinet shop that was populated by a lot of German made equipment. I bought a caliper that has decimal and fractional graduations, but my boss made me leave it at home…he thought it would be too confusing.

-- http://www.facebook.com/pages/DSO-Designs/297237806954248

View dennis mitchell's profile

dennis mitchell

3994 posts in 3036 days


#4 posted 01-10-2010 06:25 PM

One of the all time worst teachers I ever had taught metrics. Talk about complicating simple stuff…she had adults in tears. Just proving if you really want to screw things up you need a college degree!

View hokieman's profile

hokieman

163 posts in 2475 days


#5 posted 01-10-2010 06:41 PM

The metric system makes more sense???? What the heck is a kilopascal per square centimeter? I prefer psia and psig. Degrees centrigrade is not as precise as degrees farenheit where the divisions are smaller so you tend to get a little more precise. Metric system could not come up with their versions of degrees or time. Ever heard of a metric clock with 10 somethings per day? What the hell is a newton? Or a yoctonewton, yottanewton, zeptonewton and a zettanewton for that matter? Shoot, they are all numbers that are relative to some type of measure so what’s the difference and why does anyone have to change?

View LeChuck's profile

LeChuck

419 posts in 1784 days


#6 posted 01-10-2010 07:13 PM

To me the metric system makes a lot more sense and makes conversions a hell of a lot easier. It’s a modern system, everything being a direct multiple of something else, not involving esoteric formulas. I got my share of crazy stuff when going through med school and university. Thank goodness the scientific world uses metric. That said, since I’m French, I grew up with it and used it exclusively until I was 30 and moved to the US. A few years later I started to get interested in woodworking and learned the terms and theory of it in the US, and just got used to it. Now back here it’s a bit strange to have to re-adapt, but eventually I’m slipping back to metric naturally as it’s just a lot simpler. One difficulty though is that with the cost of things here, I buy a lot of things from the UK and sometimes from the US. For example, my router bits are imperial. Gotta juggle both at the same time, although it seems that more and more things in the UK are metric as well.

-- David - Tucson, AZ

View GMman's profile

GMman

3902 posts in 2419 days


#7 posted 01-10-2010 07:31 PM

In the USA a gallon or quart is smaller than a Canadian or English gallon or quart, what would you call that measurment US??

View KayBee's profile

KayBee

1016 posts in 1968 days


#8 posted 01-10-2010 07:40 PM

I’ve worked in both standard and metric systems. They both have their annoyances. But what really gets me is when they USE BOTH SYSTEMS ON ONE MACHINE!!! That’s just wrong. You’re working away with you’re standard tools out and suddenly, nothing fits. It’s metric! Now you gotta get out your standard tools or strip what you’re working on. One or the other, I don’t care, but choose.

-- Karen - a little bit of stupid goes a long way

View Maclegno's profile

Maclegno

224 posts in 1783 days


#9 posted 01-10-2010 07:47 PM

As a Scotsman living in Italy I am very conversant with both systems and use whichever suits the job (all my rules have both systems. For example I use metric for drill/screw sizes e.g. I use a 5mm drill to drill a 5mm hole for a 5mm screw using a 4.5mm drill for the pilot hole, what do I use for a No8 screw? On the other hand a third of a foot is 4”, a third of 30 cms is 3.33333333etc cms. A half of 1/16 is 1/32 while a half of .25 is .175
By the way in Continental Europe (Ex UK) the use of the comma and decimal point are reversed in writing numbers e.g 9,123 is 9.123 in USA while 9.123.456 is 9,123,456.
We should be thankful that the roman numeral system never caught on. What we call Arabic numerals actually came from India. I doubt that the length of a foot is a fraction of the Earth’s circumference but the meter is.
The fact that Britain was never conquered by napoleon is probably the reason you Americans use the current system rather than decimals, so thank us (or not). those who dislike the decimal system should be grateful the Babylonian system died out (almost) they had a base of 60! We still use it for angular measurements and time.
The “imperial” system was first standardised in Scotland

-- Maclegno,Scotsman in Italy

View Maclegno's profile

Maclegno

224 posts in 1783 days


#10 posted 01-10-2010 07:48 PM

As a Scotsman living in Italy I am very conversant with both systems and use whichever suits the job (all my rules have both systems. For example I use metric for drill/screw sizes e.g. I use a 5mm drill to drill a 5mm hole for a 5mm screw using a 4.5mm drill for the pilot hole, what do I use for a No8 screw? On the other hand a third of a foot is 4”, a third of 30 cms is 3.33333333etc cms. A half of 1/16 is 1/32 while a half of .25 is .175
By the way in Continental Europe (Ex UK) the use of the comma and decimal point are reversed in writing numbers e.g 9,123 is 9.123 in USA while 9.123.456 is 9,123,456.
We should be thankful that the roman numeral system never caught on. What we call Arabic numerals actually came from India. I doubt that the length of a foot is a fraction of the Earth’s circumference but the meter is.
The fact that Britain was never conquered by napoleon is probably the reason you Americans use the current system rather than decimals, so thank us (or not). those who dislike the decimal system should be grateful the Babylonian system died out (almost) they had a base of 60! We still use it for angular measurements and time.
The “imperial” system was first standardised in Scotland

-- Maclegno,Scotsman in Italy

View JAGWAH's profile

JAGWAH

929 posts in 1805 days


#11 posted 01-10-2010 07:53 PM

Rich
Chuck the rest up and turn down the shaft the 32nd or 64th you need and use it. You could probably do it using oil and emory cloth.

I older desperate times when I needed a 32mm hole for my cabinet door hinges and found I only had 1 1/4” forstner I’d drill the hole then apply sticky sandpaper around the bit and redrilled. Not the best of plans but works in a pinch.

-- ~Just A Guy With A Hammer~

View LeChuck's profile

LeChuck

419 posts in 1784 days


#12 posted 01-10-2010 08:07 PM

Maclegno, nothing prevents the use of fractions in the metric system. Actually, in math, physics etc, numbers are kept in fractions most of the time during calculations. You never actually apply them until the end where you must get a precise result. You keep the highest level of precision for as long as possible. By the way, a third of 30cm is 10cm. Perhaps you wanted to say a third of 10cm. That said, in woodworking why would you choose to use 10cm and then divide it by 3? Just like when using inches, use numbers that will be practical for your project. Use 9cm and then divide it by 3. Fractions are fractions, no matter which system. Of course, if we limit it to woodworking, imperial is just fine, doesn’t make much of a difference.

Now riddle me this, without looking up a conversion table: how many cubic inches is a gallon?

That’s a simple volume conversion using the metric system. How many cubic centimeters are 3 liters? 3000. That represents (for example) a volume of 30cmx10cmx10cm.

If I have a volume of 50cmx20cmx20cm, how many liters is that. 20 000 cm3 = 20 liters. If it’s water, we can also dumb it down and say it weighs 20kg. By the way, water boils at 100°C and freezes at 0°C

Can you tell quickly how many quarts are contained in a 25”x15”x15” box?

I’m not here to give or do math riddles, but the metric system does make all this stuff a lot more straightforward, although for woodworking it doesn’t make much difference, except as Rich mentions, it’s not very practical to have a little bit of both.

When I started again here I was really wondering if I would continue to use “imperial” or get used to metric for woodworking. It was an important decision because it mattered in which tools I would buy, rulers, squares, buying a router in the UK means it will use half-inch bits, not 12mm bits. And bits in France are more expensive. Same thing for the standard thicknesses that wood is sold at in stores, 10mm, 18mm etc. Then there’s the matter of websites. Frankly, there’s barely anything here. Most of the woodworking tutorials, projects and material that I will read will use inches. I guess I’ll just have to deal with it. I have imperial router bits but a whole box of metric forstner bits…Got some rulers with both, a digital calipers that does it all.

-- David - Tucson, AZ

View richgreer's profile

richgreer

4525 posts in 1796 days


#13 posted 01-10-2010 09:15 PM

Wow! I didn’t expect this much reaction on this subject. I also didn’t want to get into a debate over the merits of metric versus imperial. My main point is that having 2 systems of measurement in common use is, in itself, a problem. I might expand on that statement and say having 2 systems of measurement in common use, regardless of what they are, is a problem.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View stefang's profile

stefang

13529 posts in 2056 days


#14 posted 01-10-2010 09:19 PM

With great authority I can say that the best system is the one you know and love. I have to use the metric system which is the standard here in Norway. 1 meter divided by 100 is a centimeter, which divided by ten is a millimeter. What could be easier? Decimals are easier to calculate and even easier when they are divisible by 10. I have to admit I’m a math idiot and the metric system was probably devised for others like me. I love it! I make fewer measuring mistakes with it and can calculate measurements in my head. However, I can well understand the agony of having to endure two different systems at the same time. Not to mention all the measuring equipment out there and the related nuts, bolts, and you name it with imperial measurements. VERY difficult to convert. Once you are on the road to hell it is hard to get off!! Anyway, unlike you unlucky people, I don’t have to worry about it. I bought all my tools including measuring devices here in Norway (probably at twice the price you pay) so I have no worryies and just feel sorry for you folks who have this problem. Ok. I’m finished. Great to get that off my chest. Hope you didn’t mind. Have a good day everyone!

-- Mike, an American living in Norway.

View Brad_Nailor's profile

Brad_Nailor

2531 posts in 2679 days


#15 posted 01-10-2010 09:38 PM

Like I said..it’s what your comfortable with….if you say its two meters wide…I have to think about it..if you say its about 6 1/2’ wide then I can visualize it..

-- http://www.facebook.com/pages/DSO-Designs/297237806954248

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