Why… Why… Why…
Are the units on the field that FRC provides in decimal inches.
Either use decimal meters or fractional inches/ feet and inches.
Or provide us with a tape measure with decimal inches on it
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I know they exist. Here is one Amazon.com
But are they available at a hardware store
I can’t speak to the design or build experience, but decimals are a bit more convenient for code than feet/inches. (That being said, it’s not that hard to take a measurement that’s, say, 2’3" and just use 27")
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grrr.
If it’s not that hard, then why can’t first provide it.
grrr.
Or lets put it this way. WPILIB went out of their way to provide two ways to handle units in code.
Why can’t the field drawings team do the same.
Exactly this 
They probably did it in meters and then unit converted to decimal inches and left it there.
Sadly no
They often mess up the metric measurements as well
That’s a different rant.
If I were to guess I would say a few reasons. If you are making any of these parts on a CNC decimal dimensions are better.
Second if you get odd ball inch dimensions they are usually consequence of holding another dimension. For example you may get a length on a drawing that is 12.14 and that is because the angle that ties those pieces together needed to be 60 degrees or something like that. The length on that end just came out to whatever it did.
As for using a tape measure just use a chart find the closest match.
It will likely be close enough.
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There is always room on the chart for two sets of units
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Indeed there is, and a quick look at the typical tolerance block on a FRC field drawings shows that they absolutely allow for it:
It also helps explain why decimal and fractional inches might get used on a drawing. They mean different things, are measured with different tools and are used to communicate different measurements.
Decimal inches are a very common ‘standard’ measurement in mechanical drawings in the US. You could use fractional inches, but when features get small, or tolerances tight, fractions become really annoying to deal with, and metal working tools just aren’t graduated in them.
Fractional inches are most often used for measurements with a larger tolerance range, for objects expected to be made with a process commonly based in fractional inch tools (wood working, for example) or, very commonly, for stock sizes.
There are a lot of examples in industry, and in FRC, where fractional inch dimensions would probably make more sense on a drawing then decimal inches. But the drawings are prepared by people, and people are creatures of habit. If your day job is designing mechanical parts with tight fits you’ll probably not know how make a great drawing for something made out of home depot 2x4s cut with a hand saw, and vise versa.
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Just to really stir the pot:
The team drawings appeared to have both decimal and fractional.
The full field CAD is provided, so if you really want the fractionals for a particular part, you can make your own drawing with fractional.
How about we get rid of fractional completely. Its a nonsensical system when you don’t have the ability design everything to an even 1/8" in all cases. The fields can be provided with decimal tape and laser measures.
Hey, look at the bright side it is preparing you for the work force. I work for a European company in USA and I constantly get drawings in inches, from customers, and then drawing from my own company in MM and am constantly converting, it’s a very good skill to have a solid understanding of.
In general, what are the significant figures for fractional measures?
I can measure this piece and fairly confidently state that it is 3/16" because I have a fractional ruler. Could I state that it is 0.1875" ? I don’t have enough precision to know it isn’t 0.1872" or 0.1877".
For example using the decimal ruler, I can see that it is between 0.15" and 0.2", but would be forced to estimate the 2nd digit as I can’t determine if it 0.17" or 0.18".
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Significant figures for fractional measures can be understood by considering the divisor a base-2 number, not a base-10 number.
When you are measuring in “sixteenths”, you are measuring in significant figures of 2^-4 inches.
When you are measuring in “sixty-fourths”, you are measuring in significant figures of 2^-6 inches.
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Huge fan of decimal inches here, especially for layout. Some people mix up fractions, they can be tricky to use in phone calculators, some CAD software complains (then immediately converts to decimal) etc.
That said, in order to stop people and manufacturers from doing stupid things, fractions are great. Oh, you want precision of less than an inch? Use half inches. Need finer? Try quarter inches. And etc cetera.
Just compare a metric and fractional inch wrench set. I shouldn’t need each millimeter size from like 6 to 19, but that measurement system gave way to chaos and you need almost all of those.
Fractional inch pushes manufacturers to using 1/8" increments or 1/16" at the worst, which is still 50% larger than 1mm increments.
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Exactly the same principles apply. I was always taught that you estimate to half the smallest division on the scale, and then use that as your error. So in your picture, it’s clearly closer to 3/16, so you’d say that the length is 1/16 +/- 1/32. If it was about halfway between 1/8 and 3/16, you’d say it was 5/32 +/- 1/32.
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Different people use different systems for different things. This is why, if you want to make or read drawings, you have both engineering and architectural scales. https://acementortools.org/wp-content/uploads/2020/08/Scale-Type-Basic-Summary.pdf
I’ve been in engineering so long that my brain automatically converts any fraction I see into decimal. I can’t think properly in fractional unless I am cooking.
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