Thread: But we did agree to disagree

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Almost friendly discussion lead to- Is .02 the same as.020. I say yes , he says no.

i see both as " twenty thousandths " .. when used in a machine shop venue the amount of #`s after the # 2 is indicative of the amount of tolerance that is considered to be figured in .. hence .02 may have plus or minus 10 thousandths where .020 would have plus or minus .001 thousandths

In theory your friend is right. .02 has only two digits to the right of the decimal place, which implies that the reading is in hundredths of an inch, so it could be expressed as two one hundredths of an inch. .020 has three digits to the right of the decimal place, which implies that the dimension is in thousandths of an inch---so would be expressed as twenty thousandths of an inch. As we all know, anything measured in thousandths is ten times more accurate than something which is measured in hundredths.---It gets kinda like fighting over how many angels can dance on the head of a pin---but---theoretically--your friend is correct.

$0.10, 10 cents, or a dime.......all are valued the same, but expressed differently given the supporting context of the situation. I'm with Brian on this one.

In the machinist trade, thousandths is the language.

You could say 1/8th inch....but to a machinist, it will always be .125. You want to be understood, and to communicate what you mean, without being misunderstood, do it in the common terms.

I spent a number of years working in the trade, so I am not just debating the point.

HotRodPaint:I am like you I spent many years working in the Tool & Die Industry.Normally when you saw a two place decimal (.02) you could hold that tolerance easy,usually + or - .010.When you saw a three place(.002) decimal it was usually + or - .005 which required a little thought.When you saw a four place decimal (.0002) it was usually + or -.0001 and you were usually grinding to hold that tolerance in a controlled environment with calibrated measuring instruments. I know greater tolerances are attainable but they never came my way.

I'm in Tool & Die, I build Investment Molds, and specialized in airfoils, Turbines & turbo's. We have lost most of our tolerance yrs ago, we have to be with in .005 in one place (.1), with in .001 on two place (.12), with in .0005 on three place (.123), and with in .0003 on four place (.1234) @ 72 degs.
Years ago on a .1 Number, using a scale was almost close enough, and a dial Veneer (dial very-near) was used on .001 (I have always used a micrometer) Give 10 people a veneer and you'll have 10 different numbers.

Pat

[Give 10 people a veneer and you'll have 10 different numbers.


My experience has been, give ten people a verneer caliper and they will make a career out of trying to figure out the dimension, never get it right and say that is allowable tolerance. I do know an elderly gentleman who can read a verneer as accuratly as a mic. Says his first lathe was ran by a foot treadle till he got a steam engine to run it.

.02 and .020 are the same measurement. Tolerance is determined by the engineers.

Originally Posted by Dave Severson

.02 and .020 are the same measurement. Tolerance is determined by the engineers.

Dave you are right,it's just a number.The designer determines where you should be tolerance wise w/n that number.

Years ago at IBM they tried to set an example to the world .Go with the Metric System it's simpler to use.We did double tolerancing to try and sell the idea.Result- Lots of training and money wasted.Most of the Tool Makers and Machinist hated it. I don't know what system is being used in Industry,but with all the work (jobs) going off shore (primeraly China) the system of choice I think would be Metric.

Originally Posted by Don Dalton

Dave you are right,it's just a number.The designer determines where you should be tolerance wise w/n that number.

Years ago at IBM they tried to set an example to the world .Go with the Metric System it's simpler to use.We did double tolerancing to try and sell the idea.Result- Lots of training and money wasted.Most of the Tool Makers and Machinist hated it. I don't know what system is being used in Industry,but with all the work (jobs) going off shore (primeraly China) the system of choice I think would be Metric.

Ah, yes--the good old metric system!!! When I started in engineering in 1965 everything was British Imperial---Feet, inches, and pounds. I worked along, quite happily, measuring everything in sixteenths, thirty seconds, and thousanthths of an inch. Then in about 1974, our political leaders, in a fit of uninformed idiocy, decided that Canada was going to go metric, to "secure our future in trading with European business partners". Of course, the dumb shits never stopped to realize that out major trading partner was not Europe, and really hadn't been since the fur trappers hung up their traps. It was the good old USA, and they had no intention of going metric. Then, there ensued about 10 years of absolute insanity in Canada. Nobody knew how hot or cold it was anymore (What the Hell is a Celcius???)---Nobody knew how much they were buying at the grocery store anymore (Uh, Give me 17 grams of meat please). Aeroplanes ran out of fuel, and had to make emergency landings in Aswipe, Alberta at abandoned airstrips (Well Gee, they put 500 litres of fuel in at Toronto---Ya mean thats not the same as a gallon???) Everybody in engineering nearly went crazy, learning all this new metric system. Then we found that when our engineering drawings hit the shop floor, the first thing that happened was that the shop foreman set down with his calculator and converted everything back to British Imperial---because all the readouts on all the mills, lathes, burning tables, etcetera were still calibrated in inches, and could not operate with metric measurements. After numerous machining disasters, all Canadian engineers and designers were told to use a "dual Dimensioning" system, whereby we had to put British Imperial AND metric dimensions on all machine shop drawings. Of course, this resulted in so many dimensions on shop drawings that the poor shop guys could no longer even read the damn drawings--they couldn't see the outline of the part because of all the stupid numbers on the engineering drawings. Now we have gone full circle---and the shops that build stuff for Canada and USA want everthing in inches---forget that metric stuff. The big multi national companies lke Volkswagen, Honda, etcetera want their stuff in Metric---None of that Inch crap. Damn, I shoulda been a hair stylist!!!

Maybe I am out of touch. I worked for Hyster Corp. making production parts, and obsolete replacement parts. After that I worked for a foundry, machining mining machine components. I've never even seen a drawing done in hundredths of an inch, and the tolerances were usually spelled out, or an engineer would tell me what he wanted. The most exteme tolerances I worked in were .0003

In school I was taught that .020 is two one hundreths and .020 is twenty one thousanths. They are both the exact same thing. You can say Tomato or you can say Tomatoe. Same thing.

.02 and .020 are NOT the same.

If something measures out to .02 it might be anywhere from .02 - .029

.020 is anything from .0201 to .0209

Your friend thinks it doesn't matter? Then tell him to check the prices at the gas pumps. They COULD leave it at .01 but they don't. they take it to .001 and they do it to make MORE MONEY.

.02 ends because there is only an expected 0 for infinity
.020 """ """ """ """ _______________________""""""""" etc
they are the same measure ..
when you make it .021111111111111 then it is not the same measure as
.0209999999999999...