Metric Moron???

[george wilson]

There was some kind of foul up at NASA some time back,when someone used metric (or vice versa) measurements on an inch plan,or something to that effect. Anyone remember? Think it was about a space probe.

[Wilbur Pan]

how do you guys measure something thats less then 1mm? or how do you divide something evenly? such as 33mm divided by 5 do you round up? down? just kind of eyeball it on the tape measure? it doesnt seem very accurate to me

How do you divide 1-1/2" into 5? By the same logic, you have to figure out how to measure 3/10" with a ruler that's marked in 1/8" or 1/16" increments the vast majority of the time. This is just as inaccurate, and maybe even more so.

One advantage of using metric is that you can think in terms of 6mm chunks, which is really close to 1/4". So instead of 1/4", 1/2", 3/4", or 1", think of 6, 12, 18, and 24mm. This makes dividing by three much easier in metric than in the English system.

Me, I wind up using story sticks and cutting pieces to fit anyway, so it's a bit of a moot point. But for the times that I have had to measure, metric has been easier to deal with than English.

[Wilbur Pan]

There was some kind of foul up at NASA some time back,when someone used metric (or vice versa) measurements on an inch plan,or something to that effect. Anyone remember? Think it was about a space probe.

That was the Mars orbiter, in 1999.

[Ed Breen]

I thank you all for your words of wisdom. You'd think that after all the math I went through in 20 years of the education process I would have been exposed somewhere along the way. But I seem to have misplaced my old slate and chalk. My photography and the old 35mm/50mm stuff should have prepared me.
I feel quite up to conquering metric.
Ed

[Chris Barnett]

Lets use 5 3/8 so there is no duplication of numbers...so easy. The whole number 5 times the denominator (bottom) = 40, add the numerator 3 for a total of 43. Place this result over the original denominator 8, gives 27/8ths. Now doubling the denominator 8 gives 16, so 43/16 is half of 5 3/8. Now all you must remember is how many 16s are there in 43..which is 2 [16 x 2 =32], so 43-32 = 11. Therefore one half of 5 3/8 equals 2 11/16.
Proving this we use metrics....11/16 of 25.4 mm/inch = 17.4625, plus 2 times [25.4 = 50.8], is 17.4625 + 50.8 = 68.2625. Since 25.4 mm = 1 inch, 68.2625 = 2.68 inches, which we know is correct because 11/16 = .6875. The difference between 2.6875 and 2.68 = .0075 which is the thickness of the finish you apply .

Oh, the above post, they missed Mars!

[Chuck Wintle]

I agree with the others when it comes using the metric system...don't try to go convert between the two...it causes a lot of confusion. I found the problem with metric, at least for me initially, was its simplicity. I was so used to working with the standard system and its difficulties that the ease of conversion initially caused some problems.

[Jim Watts]

Metrics are inherently dangerous.
Don't use metrics

The plain fact is that more industrial accidents occur when metrics are used than English.
Be safe use English.

I challenge you to provide a credible example or citation that doesn't involve conversion errors...

[Glen Gunderson]

I challenge you to provide a credible example or citation that doesn't involve conversion errors...

He trots that out every time a metric thread comes up, I guess it's a bit of a running joke in his own mind. What he says is true, since the vast number of workers around the world operate under the metric system it's only logical that there would be more accidents under it.


See here:

http://sawmillcreek.org/showthread.p...ic#post1045818


and here:

http://sawmillcreek.org/showthread.p...ric#post943103


and here:

http://sawmillcreek.org/showthread.p...ric#post654071


and here:


http://sawmillcreek.org/showpost.php...2&postcount=27

[Mike Wellner]

I like this
http://www.worldwidemetric.com/metcal.htm

[Jim Watts]

He trots that out every time a metric thread comes up, I guess it's a bit of a running joke in his own mind. What he says is true, since the vast number of workers around the world operate under the metric system it's only logical that there would be more accidents under it.


See here:

http://sawmillcreek.org/showthread.p...ic#post1045818


and here:

http://sawmillcreek.org/showthread.p...ric#post943103


and here:

http://sawmillcreek.org/showthread.p...ric#post654071


and here:


http://sawmillcreek.org/showpost.php...2&postcount=27

I've been had - he got me to go off half cocked. He's logically correct...

[Karl Brogger]

I've mulled over the SI vs Imperial for some time. I've come to the conclusion it does not matter. Its just a benchmark that we've all agreed on and its all the same and doesn't matter what its based on whether its the length of King Henry IIV's foot, or the speed of light through a vaccum.

I don't think I'd do well remembering that studs are 40.67cm on center either. The only advantage I really see is that cabinet makers rarely use feet and inches. Its almost solely inches, but architects almost always use feet. I have a tough time converting 12' 7-3/8" into 151-3/8" with out thinking about it. I think alot of carpenters do not like the idea because of decimals as well, but if you spend enough time punching numbers into a CAD program or a TigerStop that goes away pretty quickly too.

[Mike Gager]

How do you divide 1-1/2" into 5? By the same logic, you have to figure out how to measure 3/10" with a ruler that's marked in 1/8" or 1/16" increments the vast majority of the time. This is just as inaccurate, and maybe even more so.

One advantage of using metric is that you can think in terms of 6mm chunks, which is really close to 1/4". So instead of 1/4", 1/2", 3/4", or 1", think of 6, 12, 18, and 24mm. This makes dividing by three much easier in metric than in the English system.

Me, I wind up using story sticks and cutting pieces to fit anyway, so it's a bit of a moot point. But for the times that I have had to measure, metric has been easier to deal with than English.

19/64 would be the closest to your 1 1/2" divided by 5 example. you could easily measure that on a ruler with 64th marks

[Steve Rozmiarek]

Lets use 5 3/8 so there is no duplication of numbers...so easy. The whole number 5 times the denominator (bottom) = 40, add the numerator 3 for a total of 43. Place this result over the original denominator 8, gives 27/8ths. Now doubling the denominator 8 gives 16, so 43/16 is half of 5 3/8. Now all you must remember is how many 16s are there in 43..which is 2 [16 x 2 =32], so 43-32 = 11. Therefore one half of 5 3/8 equals 2 11/16.
Proving this we use metrics....11/16 of 25.4 mm/inch = 17.4625, plus 2 times [25.4 = 50.8], is 17.4625 + 50.8 = 68.2625. Since 25.4 mm = 1 inch, 68.2625 = 2.68 inches, which we know is correct because 11/16 = .6875. The difference between 2.6875 and 2.68 = .0075 which is the thickness of the finish you apply .

Oh, the above post, they missed Mars!

Chris, you lost me, but illustrated the reason that I like the metric system, no stinking fractions! I think that some of our minds think in decimals, and some fractionally. Mines definatly decimal.

[Gene Howe]

Metrics are inherently dangerous.
Don't use metrics

The plain fact is that more industrial accidents occur when metrics are used than English.
Be safe use English.

OK, Cliff. But, why?

[Gene Howe]

Well, I have a problem with metrics. Not the system, but it's uneven applications.
Sheet goods are an example. I want to make some egg crate dividers for drawers. I buy 1/4 ply. It's not. My dado set will not produce a 7/32 dado!
There are quite a few other (used to be simple) little projects that I do that will now be more difficult. Yeah, I know, hardwood faced MDF is (usually) 1/4. But I don't like the stuff. And, BB is about 200 miles away.

I ordered a little gadget from Bridge city called the KM-1 Kerf Maker. Cost me over 70.00 with shipping. Now, I'll be able to use a combo or rip blade to make two cuts per groove to end up with a snug fit. It really ticks me off! $70.00 and twice the cut time?!?!

Either make some mm sized blades or give me more options in sheet goods!
Rant over.
Gene