Give you a woodworking example where it matters, see if it reaonates..
You’ve got a box 10" high, 15" wide, you want to decorate the side with a few raised panels with borders, whatever. You decide that they're going to be inset ¾" from the sides, middle one will be maybe 10% larger on each side, the double spacing of 1½" between seems too wide so you want to fudge to 1⅛".
So all told width-wise you have a 15" span of which ¾ + 1⅛ + 1⅛ + ¾ is margin, so that’s 1½ + 2¼ = 3¾, you'll have 11¼ left over. You want to divide it into 1 + 1.1 + 1 = 3.1 pieces.
So you locate axes A and B on your slide rule, these should be double log-log, going from 1 - 100, fine for multiplications. You will also see C and D, single log-log going from 1 to 10, higher in precision, also having them next to A and B allows you to perform square roots, use the hairline on the cursor to confirm that the square root of 16 is 4 for example. You also probably have a red series that is single log-log but backwards called CI, this can sometimes be helpful for divisions, and a maybe a K scale that is triple log-log allowing cubing or cube roots. Flip it over, you might have S for sine, t for tan, L for logarithm being a linear scale.
Anyway, move the hairline on the cursor over A=11.25 to “remember” it, then put B=3.1 under the hairline and look at the place where B=1, it's around 3.625. Of course we would rather have this in eighths or 16ths, but look at (no sliding!) B=8 to find this is nearly A=29 or 29/8 inches, that 3.625 is 3⅝". And looking at B=1.1 you get that 10% larger is just 4".
So you want a 4"×8½" panel in the middle, two 3⅝"×7¼" panels on the sides, you can again get that 7¼" by moving B=1.1 next to A=8.5 and then B=1 shows 7 and change, peek up at B = 4,8,16 to see if it's best written as a quarter or eighth or sixteenth fraction.
So they're great at
- multiplying or dividing numbers, especially if they are not round
- converting those decimals to eighths or sixteenths, calculators just give you digits usually, slide rules you can quickly see what is 1x this number, 2x, 4x, 8x, 16x, makes it a snap.
Comments
Give you a woodworking example where it matters, see if it reaonates..
You’ve got a box 10" high, 15" wide, you want to decorate the side with a few raised panels with borders, whatever. You decide that they're going to be inset ¾" from the sides, middle one will be maybe 10% larger on each side, the double spacing of 1½" between seems too wide so you want to fudge to 1⅛".
So all told width-wise you have a 15" span of which ¾ + 1⅛ + 1⅛ + ¾ is margin, so that’s 1½ + 2¼ = 3¾, you'll have 11¼ left over. You want to divide it into 1 + 1.1 + 1 = 3.1 pieces.
So you locate axes A and B on your slide rule, these should be double log-log, going from 1 - 100, fine for multiplications. You will also see C and D, single log-log going from 1 to 10, higher in precision, also having them next to A and B allows you to perform square roots, use the hairline on the cursor to confirm that the square root of 16 is 4 for example. You also probably have a red series that is single log-log but backwards called CI, this can sometimes be helpful for divisions, and a maybe a K scale that is triple log-log allowing cubing or cube roots. Flip it over, you might have S for sine, t for tan, L for logarithm being a linear scale.
Anyway, move the hairline on the cursor over A=11.25 to “remember” it, then put B=3.1 under the hairline and look at the place where B=1, it's around 3.625. Of course we would rather have this in eighths or 16ths, but look at (no sliding!) B=8 to find this is nearly A=29 or 29/8 inches, that 3.625 is 3⅝". And looking at B=1.1 you get that 10% larger is just 4".
So you want a 4"×8½" panel in the middle, two 3⅝"×7¼" panels on the sides, you can again get that 7¼" by moving B=1.1 next to A=8.5 and then B=1 shows 7 and change, peek up at B = 4,8,16 to see if it's best written as a quarter or eighth or sixteenth fraction.
So they're great at
- multiplying or dividing numbers, especially if they are not round
- converting those decimals to eighths or sixteenths, calculators just give you digits usually, slide rules you can quickly see what is 1x this number, 2x, 4x, 8x, 16x, makes it a snap.
Sounds like i might even be able to crack CSS layouts with one of these things.