~3.2mm. I can’t think of any real world application which needs fraction of a millimeter which doesn’t include ah calculator and some damn exact measuring tools.
Well I’m building a table right now, and it was pretty easy to choose a size for a mortise and tenon in my 3/4" stock, a third of 3/4" is 1/4". If I wanted half its width, that’s 3/8". Mental math is a lot easier than “What’s a third of 19mm.” In the wood shop, I rarely have to divide things by five or ten. I have to divide things by two, three and four a lot.
I’m building a shaker table out of white oak. I milled all my stock to 3/4" thickness.
Just today, I resawed a board to 3/8", or half its original thickness. I glued two boards together to make 3/2" (1 1/2") thick table legs, and I cut mortises 1/3 the thickness of the stock, or a nice even 1/4".
I’m familiar with the metric system, I learned chemistry and physics in metric. I prefer woodworking in fractional inches because metric seems like a bigger pain in the ass
okay then my answer to the hypothetical is 9.5/3, which is every bit as easy to find on any measurement device, or to use for any practical purpose, as 1/24th
You know what really gets me about these threads? Everybody being like “Can you believe Americans are stupid enough to comprehend fractions? I’m too smart to comprehend fractions.”
No, like I said in my edit, my drafting ruler has a three or four inch long 24ths scale.
Even if it didn’t, having to mark the halfway point between graduations is hardly helpless.
18ths would need two divisions by three, but thankfully dividing a known measured length by three is easy with a piece of string.
There’s a reason millennia of our ancestors used fractional divisions of standard lengths and weights. They can be measured, calculated and double checked (this one is doubly important for stuff that really pisses off metroids like the hogshead/tun) using cheap, universally available tools and deceptively simple mathematics that have been the foundation of what constituted a good education for centuries.
18ths would need two divisions by three, but thankfully dividing a known measured length by three is easy with a piece of string.
what kind of cartoon fantasyland do you live in where it’s easier to find a piece of string than it is a calculator?
also, all of this is assuming you have your drafting ruler to hand
do you carry it around with you in your pocket on a day-to-day basis? some deep fucking pockets you’ve got there, although I suppose you already that to the 1/24th inch
They can be measured, calculated and double checked
my guy, we’re talking about accuracies of millimeters here: you’re not “double checking” your 12" ruler is accurate by slapping your bare carpet gripper up on the drafting table
well, considering i was sitting in the bathroom looking at my phone while wearing clothes when i saw your response, i’d say string and a calculator were both equally close at hand.
only one of those can be used as a measuring tool, though… I guess you could mark off how many calculator lengths something is and measure it later. ngl, i hung a shelf using that technique once, but i wouldn’t use it to find one third of a length. the nice thing about string is that if you don’t have a measuring stick you can always stuff it in your pocket and measure it later when the appropriate tool is at hand.
apologies for any confusion about checking measurements, i wasn’t referring to using my own foot to verify the length of a line, but the common practice of using fractional mathematics to make and verify calculations thousands of years ago and to this very day. we have records of this method being used across language and unit barriers in the ancient world.
there’s another post earlier itt blaming the mars climate orbiter failure on sae unit conversion but nasa puts the blame on itself for not double checking the software and measurements they got back from lockheed. I remember back in the day hearing about that failure on the news and seeing how it was not a problem of difficulty of conversion between the compound units involved, but failure to actually convert between them at all!
since you brought up calculators, there’s a salient point to be made here using a long winded anecdote: when i was in school there was a point in time when suddenly teachers began providing calculators for the exams. this wasn’t that magic moment when the mathematics became just too complicated to expect a middle schooler to do it all on paper. last years class had to use longhand, this years class were provided little blue texas instruments scientific units with a ten digit display and helpful guide to performing logs and other operations that would have been taught using super and subscripts glued to the inside of the cover that would be taken back up at the end of the test.
this didn’t happen going from one grade level to another, but right smack dab in the middle of the academic year. a whole classroom of students yanked bodily into the digital age.
when the parents found out you’d think the questions were gonna be written on the proctors inner thigh. “i had to do it by hand, my kid should too!” “you’re supposed to be teaching them math, not how to use a calculator!” and it’s sister “you’re supposed to be testing their ability to do math, not use a calculator!” but the most common one by far was “they’ll all just get the right answers and we won’t know who studied and learned.”
when the grades came in there was almost no change from last years class.
there were some individual students who did better or worse than their test history would suggest and a whole bunch of new common wrong answers, but by and large aside from errors the ability to perform calculations in response to a prompt was unaffected by ten signed digits of precision.
how could it be that a calculator made no difference?
it turns out that understanding what a question was asking for, verifying ones work and recognizing wrong answers that needed to be rechecked couldn’t be performed by the little blue rectangles.
and many years (and measurements) later i have the same outlook about metrology: comprehension of the goal of a measurement gives you a much better chance to get it right than a calculator.
Quick off the top of your head, what’s a third of 9.5mm?
~3.2mm. I can’t think of any real world application which needs fraction of a millimeter which doesn’t include ah calculator and some damn exact measuring tools.
Quick off the top of your head, why would I use fractions of a cm instead of mm? It’s a workaround for a shit system
Well I’m building a table right now, and it was pretty easy to choose a size for a mortise and tenon in my 3/4" stock, a third of 3/4" is 1/4". If I wanted half its width, that’s 3/8". Mental math is a lot easier than “What’s a third of 19mm.” In the wood shop, I rarely have to divide things by five or ten. I have to divide things by two, three and four a lot.
I don’t know anything about carpentry, so I’ll take your word on it.
My best guess is that the standards are different. For example 2cm stock instead of 1.9. Then only the 1/3 is problematic.
I’m building a shaker table out of white oak. I milled all my stock to 3/4" thickness.
Just today, I resawed a board to 3/8", or half its original thickness. I glued two boards together to make 3/2" (1 1/2") thick table legs, and I cut mortises 1/3 the thickness of the stock, or a nice even 1/4".
I’m familiar with the metric system, I learned chemistry and physics in metric. I prefer woodworking in fractional inches because metric seems like a bigger pain in the ass
We are communicating through writing on an asynchronous web forum.
what’s a 1/3 of 1/8th of an inch?
1/24th.
Fractions of fractions are easy, just multiply the denominators.
okay then my answer to the hypothetical is 9.5/3, which is every bit as easy to find on any measurement device, or to use for any practical purpose, as 1/24th
Well I’m not the person who initially asked you that, I’m just someone who recognizes how easy it is to work with fractions.
Also I have a ruler with 1/12s graduations and while it’s not 24ths, my neighbor has one marked like that.
E: my drafting ruler has a short 24ths scale
You know what really gets me about these threads? Everybody being like “Can you believe Americans are stupid enough to comprehend fractions? I’m too smart to comprehend fractions.”
thinking that knowing that 1/3 * 1/8 = 1/24 is something that anybody wouldn’t know is stupid
the point is the impracticality of the result being essentially equivalent to 95/3
so in other words you’re helpless in that situation?
we can play the same game with 1/18th or whatever if you want
No, like I said in my edit, my drafting ruler has a three or four inch long 24ths scale.
Even if it didn’t, having to mark the halfway point between graduations is hardly helpless.
18ths would need two divisions by three, but thankfully dividing a known measured length by three is easy with a piece of string.
There’s a reason millennia of our ancestors used fractional divisions of standard lengths and weights. They can be measured, calculated and double checked (this one is doubly important for stuff that really pisses off metroids like the hogshead/tun) using cheap, universally available tools and deceptively simple mathematics that have been the foundation of what constituted a good education for centuries.
what kind of cartoon fantasyland do you live in where it’s easier to find a piece of string than it is a calculator?
also, all of this is assuming you have your drafting ruler to hand
do you carry it around with you in your pocket on a day-to-day basis? some deep fucking pockets you’ve got there, although I suppose you already that to the 1/24th inch
my guy, we’re talking about accuracies of millimeters here: you’re not “double checking” your 12" ruler is accurate by slapping your bare carpet gripper up on the drafting table
we no longer live in the pre-industrial age
well, considering i was sitting in the bathroom looking at my phone while wearing clothes when i saw your response, i’d say string and a calculator were both equally close at hand.
only one of those can be used as a measuring tool, though… I guess you could mark off how many calculator lengths something is and measure it later. ngl, i hung a shelf using that technique once, but i wouldn’t use it to find one third of a length. the nice thing about string is that if you don’t have a measuring stick you can always stuff it in your pocket and measure it later when the appropriate tool is at hand.
apologies for any confusion about checking measurements, i wasn’t referring to using my own foot to verify the length of a line, but the common practice of using fractional mathematics to make and verify calculations thousands of years ago and to this very day. we have records of this method being used across language and unit barriers in the ancient world.
there’s another post earlier itt blaming the mars climate orbiter failure on sae unit conversion but nasa puts the blame on itself for not double checking the software and measurements they got back from lockheed. I remember back in the day hearing about that failure on the news and seeing how it was not a problem of difficulty of conversion between the compound units involved, but failure to actually convert between them at all!
since you brought up calculators, there’s a salient point to be made here using a long winded anecdote: when i was in school there was a point in time when suddenly teachers began providing calculators for the exams. this wasn’t that magic moment when the mathematics became just too complicated to expect a middle schooler to do it all on paper. last years class had to use longhand, this years class were provided little blue texas instruments scientific units with a ten digit display and helpful guide to performing logs and other operations that would have been taught using super and subscripts glued to the inside of the cover that would be taken back up at the end of the test.
this didn’t happen going from one grade level to another, but right smack dab in the middle of the academic year. a whole classroom of students yanked bodily into the digital age.
when the parents found out you’d think the questions were gonna be written on the proctors inner thigh. “i had to do it by hand, my kid should too!” “you’re supposed to be teaching them math, not how to use a calculator!” and it’s sister “you’re supposed to be testing their ability to do math, not use a calculator!” but the most common one by far was “they’ll all just get the right answers and we won’t know who studied and learned.”
when the grades came in there was almost no change from last years class.
there were some individual students who did better or worse than their test history would suggest and a whole bunch of new common wrong answers, but by and large aside from errors the ability to perform calculations in response to a prompt was unaffected by ten signed digits of precision.
how could it be that a calculator made no difference?
it turns out that understanding what a question was asking for, verifying ones work and recognizing wrong answers that needed to be rechecked couldn’t be performed by the little blue rectangles.
and many years (and measurements) later i have the same outlook about metrology: comprehension of the goal of a measurement gives you a much better chance to get it right than a calculator.