Five feet divided by three is 20 inches. Ten inches divided by three is 3 and 21/64. One third of 9/16 is 3/16 or 12/64. So you get 23 and 33/64 inches. If you have a standard tape measure, that fraction is just a smidge over a half inch. Close enough for cutting 2x4’s - and to the same level of precision as that metric conversion.
All this figured out w/o a calculator. Can’t ever find one on the job site anyway. Still looking for the 3-1/2” Philips head screws - now where the hell did that new box I just bought go?
And channel lengths in single digit nm. Pretty crazy.
My favourite part of the metric system is the simplicity that it allows for when working with formulas and equations. If the numbers going into the equation are in the base unit, the output will be in the base unit as well. E = I * R. If I and R are entered in their base units (ampere, ohm) then the result, E, will be in the base unit (volt) as well. There's no "magic" scaling factors. There's no need for a table of which unit each variable should be entered as.
I personally like "113355" for pi. Pi = 355/113 = 3.1415929.
For the everyday Joe there's little incentive to change.
I also wouldn't be surprised if manufacturers like the obscurity that comes with the imperial system. I remember one point in grad school in the US where I was trying to decide which toilet paper to buy. I was optimizing for cost. Lower cost per unit area -> better. But it was nearly impossible to see if one brand of TP offered a better deal than another because one brand listed the unit cost as $ per sheet. Another listed $ per square inch. Yet another listed $ per linear foot or per roll. Or coffee where one company lists the price per ounce and another per pound.
With the metric system it would have been pretty easy to compare TP prices as long as they were all listed in cost per unit area even if the area units were different (sq cm vs sq m, say). Or coffee prices in cost per unit weight.
Tom
Ten divided by three is not 3-21/64. It's 3-1/3 or 3-21/63.
I would also argue that to get to the 20 inches, you first have to multiply five by 12, then divide by three. Easy enough for five, but how about 345 feet?
Also, you performed five calculations to get to the result. I performed one. Which one of us will make fewer errors over time?
You don't have your phone in your pocket?
Oh, that's my favourite game. Another good one is: 15-minute tool hunt in the attic to find the tool you lost in the insulation ... somewhere. I did that recently only to find that I'd put the tool on a board behind me so it wouldn't disappear into the insulation. 🙂
Tom
1/3 is 21/64, to the nearest 64th. Anything beyond 32nds cant easily be resolved on my Stanley tape measure marked off in 16ths.
Five calculations that can be done in your head, in less time than scouring the job site for the calculator. And the phone is somewhere that it can’t get broken accidentally sitting on it. When the screw driver disappears, you go get the other one. Or even threaten to go get in the truck, drive to the hardware store and buy another. Often the threat is enough to make it reappear.
Five calculations that can be done in your head, in less time than scouring the job site for the calculator. And the phone is somewhere that it can’t get broken accidentally sitting on it. When the screw driver disappears, you go get the other one. Or even threaten to go get in the truck, drive to the hardware store and buy another. Often the threat is enough to make it reappear.
I have a hair trimmer with a triangular drive screws.
The driver bit is triangular in shape, the thing is made in China.
American million is 10E6, billion is 10E9, trillion in is 10E12, and so on.
UK million is 10E6, billion is 10E12, trillion is 10E18.
10E6 means 1 followed by six zeroes, and so on.
We have a legacy of inch measures here, the new machines are firmly metric. So are the users of the CAD equipment.
And NASA used slide rules for the Apollo program it seems, so they worked, too.
17 and 23 are prime numbers, why use those as denominators?
We learned both decimal and fractional arithmetic in school.
Now my scientific calculator and maybe my smartphone can do fractional math...if needed.
Most times, while cutting metal, or using fasteners, we buy what is available, in standard pitch.
But some people deliberately use a non-standard pitch, so the customer does not use a device which may not suit, which I find is mean.
I made part of a kidney stone removal device for the inventor, he put 10 x 0.75 pitch, instead of 1.0 (standard), because he had to certify the system would work. Had to get special taps and dies made, took a lot of rejection.
He sells it for 1000s of $, feels it is worth it.
The driver bit is triangular in shape, the thing is made in China.
American million is 10E6, billion is 10E9, trillion in is 10E12, and so on.
UK million is 10E6, billion is 10E12, trillion is 10E18.
10E6 means 1 followed by six zeroes, and so on.
We have a legacy of inch measures here, the new machines are firmly metric. So are the users of the CAD equipment.
And NASA used slide rules for the Apollo program it seems, so they worked, too.
17 and 23 are prime numbers, why use those as denominators?
We learned both decimal and fractional arithmetic in school.
Now my scientific calculator and maybe my smartphone can do fractional math...if needed.
Most times, while cutting metal, or using fasteners, we buy what is available, in standard pitch.
But some people deliberately use a non-standard pitch, so the customer does not use a device which may not suit, which I find is mean.
I made part of a kidney stone removal device for the inventor, he put 10 x 0.75 pitch, instead of 1.0 (standard), because he had to certify the system would work. Had to get special taps and dies made, took a lot of rejection.
He sells it for 1000s of $, feels it is worth it.
That sums up assembly quality of Murican cars in one sentence. Well done! 🙂 And that level of precision is fine when building a fence. But if you're off by 1/64" in the hole placement for a part on a PCB you'll often find that the part won't fit. Or if the hole in the chassis is 1/64" off from the location of the button you'd like to poke through the panel, it'll be visibly off centre.
Tom
Shifting gears in bumper to bumper traffic is a pain.
I learned to drive in a Mahindra made Jeep, in rim deep sand, 1st gear, 4x4, low range...can't do that on an auto, the clutch control is important.
Depends, here CVT are coming in slowly, not many dual clutch, something called AMT is fitted.
Auto transmission with torque converter means loss of fuel efficiency, and here gas prices are high compared to income.
Horses for courses...
I learned to drive in a Mahindra made Jeep, in rim deep sand, 1st gear, 4x4, low range...can't do that on an auto, the clutch control is important.
Depends, here CVT are coming in slowly, not many dual clutch, something called AMT is fitted.
Auto transmission with torque converter means loss of fuel efficiency, and here gas prices are high compared to income.
Horses for courses...
Stick is more control in all situations, especially in difficult and dangerous ones.
I remember my first auto transmission gaffe. I am going down Rocky Mountain continental divide in my brand new '92 4-speed auto Hyundai Elantra. It is something like 10 mile continuous downhill. About 3/4 down, there is funny smell of something burning. I stop at a turnout, open the hood, and see smoke coming out of transmission. Pull the dipstick, the fluid is discolored. Had to wait for an hour for transmission to cool down. Going further, I noticed that I wasn't the only one who had an unplanned stop there.
Then, German vs. Russian fighter planes of WW2. Me109 and FW190 had automatic engine and propeller controls, so that pilot could dedicate more attention to combat. La and Yak were all manual; they were death traps for inexperienced pilots, but experts could outmaneuvre their opponents because manual controls gave more precision and flexibility.
I remember my first auto transmission gaffe. I am going down Rocky Mountain continental divide in my brand new '92 4-speed auto Hyundai Elantra. It is something like 10 mile continuous downhill. About 3/4 down, there is funny smell of something burning. I stop at a turnout, open the hood, and see smoke coming out of transmission. Pull the dipstick, the fluid is discolored. Had to wait for an hour for transmission to cool down. Going further, I noticed that I wasn't the only one who had an unplanned stop there.
Then, German vs. Russian fighter planes of WW2. Me109 and FW190 had automatic engine and propeller controls, so that pilot could dedicate more attention to combat. La and Yak were all manual; they were death traps for inexperienced pilots, but experts could outmaneuvre their opponents because manual controls gave more precision and flexibility.
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Run a string the length of the board. Fold it in threes. There's your answer already realized. (I assume you want a cut object, not just a number.)
Do we all know that the Romans had the abacus?? Yes, no zero, but an abacus plus an experienced mind is a powerful tool.
How much 3.5" trim do I need to trim a 23" octagonal window? (Remember 1/8" for saw kerf.)
These problems are what I call "WWJD?" Not Jesus the carpenter's son, but His 'dad' Joseph. What Would Joseph Do? The blessed infant needs a cradle. And a Myrrh shelf. And a changing table. Soon enough, His own room that won't fall down in wind or rain. And Joe must have taken work for other people, if only to pay his census tax, but he probably worked 6 days a week. In a land already low on lumber. And now with two extra mouths to feed. So he knew how to figure his BoM closely.
Somewhere I wrote-up the octagonal window trim using only techniques knowable by Joseph. WWJD?
In this case the answer was: HomeDepot only had 3.5" in 12 foot lengths, too long for the ox-cart I rode in on. But they priced 5.5" trim cheaper than 3.5" trim!! And in 8 foot sticks, perfect for the minivan.
With auto transmission, hydraulic torque converter is where the kinetic energy of car going down is dissipated (converted into heat). With stick, you just shift into fourth and break with engine, which has radiator to dissipate the heat.
The torque converter is locked once the car moves at any appreciable speed, though. Downshifting in an automatic works just as well. And obviously, if the automatic is a dual clutch type, you're basically back to a manual transmission with electronic control. I downshift downhill all the time in my car with DSG.
Tom
To cut a board in thirds or any equal division you use your measuring tape or other ruler at an angle so that the length measured is 6 feet (or any easy to divide measurement unit.). Then you make a mark at every 2 feet and use a square to carry those marks to the edge.
Next we can discuss allowing for the blade width also known as the saw kerf.
Next we can discuss allowing for the blade width also known as the saw kerf.
Now to stay on topic, we can discuss where U.S. bolts and machine screw thread sizes started.
Andrew Carnegie did well making steel. However actually being an astute businessman he sought to increase his steel sales and realized he could do so by making and selling bolts! So his company latter to become U.S. Steel came out with a range of offerings. Being cost concerned his fasteners came in a standard range of sizes and one thread pitch for each diameter . For example a 1/2” bolt would be offered only in a pitch of 13 threads per inch.
Later the Society of Automotive Engineers offered a standard bolt sizing system. Their 1/2” bolt standard called for a thread pitch of 20 per inch.
As things overall got standardized there became “National Course” thread standards which were based on the bolt sizes by the steel makers and “National Fine” sizes which were the SAE sizes. To accommodate any other common sizes they became “National Special.”
I keep on hand machine screws from 2-56 to 10-32 and bolts from 1/4-20 to 1/2-13, of course along with the matching nuts and washers. I think a bit more than 300 sizes in all. (Length matters also!). I do not keep sizes known here as “Stove Bolts”. I do have a shelf of metric sized bolts that are commonly used around here.
My useful accomplishment was to build portable carts with enough shelves and compartments to hold and display the assortment, so there was no hunting for any box of bolts! Now if I can only get folks to put things back where they belong.
Andrew Carnegie did well making steel. However actually being an astute businessman he sought to increase his steel sales and realized he could do so by making and selling bolts! So his company latter to become U.S. Steel came out with a range of offerings. Being cost concerned his fasteners came in a standard range of sizes and one thread pitch for each diameter . For example a 1/2” bolt would be offered only in a pitch of 13 threads per inch.
Later the Society of Automotive Engineers offered a standard bolt sizing system. Their 1/2” bolt standard called for a thread pitch of 20 per inch.
As things overall got standardized there became “National Course” thread standards which were based on the bolt sizes by the steel makers and “National Fine” sizes which were the SAE sizes. To accommodate any other common sizes they became “National Special.”
I keep on hand machine screws from 2-56 to 10-32 and bolts from 1/4-20 to 1/2-13, of course along with the matching nuts and washers. I think a bit more than 300 sizes in all. (Length matters also!). I do not keep sizes known here as “Stove Bolts”. I do have a shelf of metric sized bolts that are commonly used around here.
My useful accomplishment was to build portable carts with enough shelves and compartments to hold and display the assortment, so there was no hunting for any box of bolts! Now if I can only get folks to put things back where they belong.
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