Metrication

RC99 · May 23, 2007

I was reading wikipedia about metrication and it says

"As of 2007, only the United States, Liberia, and Myanmar (Burma) have not adopted the International System of Units as their primary or sole system of measurement[1], although it is widely used in all countries in science, medicine, and engineering. Note, however, that at least Myanmar uses metric units on a practical basis in daily life."

So why do these countries not embrace metrication for everyday use???

Croz · May 23, 2007

The BEST thing that ever happened, METRICATION.
I see from your above post that the USA is keeping good buddies! only joking, but I do wish USA would go over to metrication, we did it and it didn't hurt that much. I am lucky to be of an age where I can switch from inches to metres with no problems, c'mon go with the flow, or do you want to become isolated?
ATB,
croz

Forrest Addy · May 23, 2007

"If God had intended us to be metric he would have given us meters instead of feet."

This in a growl from the back of the classroom where I was teaching about ball bearings and their metric sizes.

secetal · May 23, 2007

Why don,t we go all the way. A TEN day week,100 second minute,100 minute hour, etc.etc. ??

Martin

HelicalCut · May 23, 2007

I see little benefit from metrication aside from the benefit that standardisation has given. Most of my machines are imperial but that makes little difference except imperial leadscrew has disappeared from the market here.

Even before metrication here in Australia in 1974 a lot of US stuff was made to different standards, NPT and american machine screw for starters. While 600 class switchgear is useful in Australia and Europe not much other electrical gear is. Pipe and electrical conduit from any country is built to ad hoc standards. Even the imperial system in the US has it's quirks like the 16 oz pint and the short ton. Metric bolts come with all manner of head sizes, whitworth was more consistant, pity about the 55 deg thread angle.

What we need are widely applied standards but thing like supply voltage and frequency are well entrenched in any country and in the age of cnc building to any spec isn't too difficult.

anteekfreek · May 23, 2007

I haven't seen a customer part print for years that was drawn in inches.....I think it was for a Chrysler service van headlamp, and that really seemed odd at the time (13 years ago).

Many of our internally drawn gage and fixture design prints are in both inch and metric [XX.XXX].

Our toolroom guys are like I used to be. They want everything in inches. If a part is 0.076mm out of tolerance they ask "how many thousandths is that ?"

Even that's a rather limited use of the metric system for me; basically small metric units. Most everything is described in millimeters or microns.

Outside of my workplace I don't speak of kilometers, meters or decimeters, I speak of miles, yards, feet and inches.

If I were looking to buy a tape measure, I'd buy one graduated in inches though. Of course we buy our milk and gasoline by the gallon, but our soda pop comes in two-liter (litre) bottles.

My Starrett micrometers are all in inches...and I like them that way. But just try to work on a late model car these days with a set of inch wrenches and sockets.

Wow....we're all messed up eh ?

SND · May 23, 2007

They teach metric in school in Canada. But then in the "real world" its really not used all that much. Most engineering companies that I make parts for still use imperial. As far as I know many of the companies using Metric in Canada are not from Canada, they're European branches.

I hate getting drawings that have both metric and imperial measurement on every details. And things like #10-24 20deep. 20 inches deep? oh no 20mm.

Steel Roller · May 23, 2007

Screw the Euro and there system.

AeroncaChamp · May 23, 2007

"Still waiting for the metric system"
(Seen on T-shirt)

The mind boggles at the cost of conversion in an industrial country with the GDP of the USA. Many, many billions of $$$s invested in machines and tooling graduated in inches.

I wonder, do CNC machines operate in metric or "English" (or both)?

MattW · May 23, 2007

Hey Secetal, I'm on board with the "metric time" conversion, but we need to do something about that pesky 365.25 day reveolution around the sun.

I think if we expell the right number of lawyers from the planet at just the right trajectory, we could modify our orbit to exactly 100 days.

You start gathering them up, and I'll build the catapult. (we can fine tune the orbit with further launchings of polititians into space.)

Dr. Rob · May 23, 2007

The USA was officially metricized a hundred-odd years ago. They just haven't gotten around to using it.

See for yourselves:

http://lamar.colostate.edu/~hillger/...-act-bill.html

dfw5914 · May 23, 2007

"I wonder, do CNC machines operate in metric or "English" (or both)?"

I guess since they pretty much all use ball screws for positioning, CNC machines do not use inch or mm, they use "degrees of rotation".

Forrest Addy · May 23, 2007

Any measurement system boils down to the least definable increment suited for the particular trade that uses it. In the machinist's trade it's about 0.0001" or 0.02MM. Everything larger is a multiple of it. Carpenters have their tolerances, dressmakers theirs and so on. Anything thereafter is a quibble over units.

I used to kid back and forth with an guy where I figured the atto-parsec was the most suitable unit for industry and trade and he preferred the Barnes something an equallty idiotic concoction of the improbably huge with the miniscule.

Trouble is customary units are customary. We think in terms of the units we learned as kids and are emotionally attached to them. The old statistics of all nations are crowded with obsolete units of land, beer, butter, and lumber. A unit is a unit but it can also be a PITA.

I don't care what units I have to work in so long as I can make conversions to the degree of accuracy I need to perform the work. You want a kitchen counter 4 cubits 2 hands and a finger long? Fine; whose are we using? Hold still now so I can calibrate a conversion from your standard to the units my tools are graduated in.

I got a calculator. I'm mathematically bullet proof.

kenh · May 23, 2007

Don't care which measuring system is used.

BUT, very interested in launching Politicians/Lawyers/Extreme Wacko Liberals!

Forrest Addy · May 23, 2007

Ken, let's just launch extreme whackos and leave it at that. Define it any tighter than that and the whackos dodging the cut will proliferate to the detriment of who ever they attach themsselves to.

gar · May 23, 2007

dfw5914:

As standard parts ball screws are made in both inch and mm. However, the encoders are likely to be binary. 12 bits binary is 4096 and that's not degrees.

My HAAS machine quantizes to about 30/1,000,000" but my smallest programmable inch increment is 0.000,1". Based on the quantizing level there is a small amount of jitter in your ability to position.

Suppose I want approximately a 0.2" pitch on the screw, but I want each step of my encoder to be 10/1,000,000" and the encoder has 16,384 steps (14 bits), then the pitch needs to be 0.163,84". Add one more binary bit of resolution and the pitch would be 0.327,68".

Maybe we should switch to a binary system rather than metric.

For mechanical things I like the English system, for scientific metric is good.

.

dfw5914 · May 23, 2007

Gar,
Is binary a measurment system or a language?

superalloy · May 23, 2007

Binary; reminds me of this joke:

"there are 10 kinds of people in this world; those who understand binary and those who don't"

Lew Hartswick · May 23, 2007

"I wonder, do CNC machines operate in metric or "English" (or both)?"

I guess since they pretty much all use ball screws for positioning, CNC machines do not use inch or mm, they use "degrees of rotation".

Ah Ha! Then we had better get rid of that pesky 360
things per rev and change to 100.

The Arabs had one thing right.
On the other hand base 12 would be much better all
around. Stupid metric.

...lew...

gar · May 23, 2007

dfw5914:

Binary is a number system where the only digits are 0 and 1. So the number 4 in decimal = 100b in binary.

Octal is based on only 0 thru 7. 10 in octal = 8 in decimal.

In the hexadecimal system we usually use the following digits: 0, 1, ..., 8, 9, A, B, C, D, E, F
10h = 16 decimal, and 10 decimal = A in hex
100h = 256 decimal
1000h = 4096 decimal
10000h = 65536 decimal.

Hexadecimal notation is used to represent binary numbers because there is a simple relationship between them. For example:
the lower case letter "m" in the ASCII alphabet can be represented as
6D in hex
0110 1101 in binary
155 in octal
109 in decimal

An internet source for the ASCII table is
www.asciitable.com

Following is 0 thru 16 decimal in hex and binary

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> 0 00 00000
1 01 00001
2 02 00010
3 03 00011
4 04 00100
5 05 00101
6 06 00110
7 07 00111
8 08 01000
9 09 01001
10 0A 01010
11 0B 01011
12 0C 01100
13 0D 01101
14 0E 01110
15 0F 01111
16 10 10000</pre>[/QUOTE]In binary to divide by 2 you shift the number one digit to the right. To multiply by 2 shift one digit to the left.

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Metrication

Diamond

Aluminum

Diamond

Hot Rolled

Stainless

Cast Iron

Diamond

Plastic

Cast Iron

Hot Rolled

Hot Rolled

Stainless

Diamond

kenh

Guest

Diamond

Stainless

Stainless

Cast Iron

Hot Rolled

Stainless

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