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| massive88:
You can easily find the exact center with just a ruler. Pick a length of a chord that makes sense for the size of the circle that you are dealing with that makes an even measurement, say 1" for example. Move the ruler along the radius till two points of the circle match your dimension (1" here). Draw two chords that are 1" making an extra tick at the half way mark, 1/2" in this example. If your ruler has a square bottom, make a perpendicular line from your half way mark on each line toward the center of the circle. The two perp lines will cross, and X marks the spot. Heres a quick sketch of this method in Autocad, on a 2" diameter circle using the example numbers above. |
| ivwshane:
--- Quote from: massive88 on August 19, 2008, 06:24:17 pm ---You can easily find the exact center with just a ruler. Pick a length of a chord that makes sense for the size of the circle that you are dealing with that makes an even measurement, say 1" for example. Move the ruler along the radius till two points of the circle match your dimension (1" here). Draw two chords that are 1" making an extra tick at the half way mark, 1/2" in this example. If your ruler has a square bottom, make a perpendicular line from your half way mark on each line toward the center of the circle. The two perp lines will cross, and X marks the spot. Heres a quick sketch of this method in Autocad, on a 2" diameter circle using the example numbers above. --- End quote --- That's the same thing as my suggestion but with two extra lines:p |
| massive88:
--- Quote from: ivwshane on August 19, 2008, 11:11:56 pm ---That's the same thing as my suggestion but with two extra lines:p --- End quote --- Yes but less math and measuring ;p Both will work splendidly without the aid of a compass :cheers: |
| Paulson:
What about if you slide a rule up & down your circle so you can find the widest part. Then mark the centre? Sounds easy to me... Just a thought... Paulson (uk) |
| pmc:
--- Quote from: Paulson on August 20, 2008, 12:14:36 pm --- What about if you slide a rule up & down your circle so you can find the widest part. Then mark the centre? --- End quote --- Yah. And if you do it twice (once up and down and once left and right), you can reduce any measuring error by using the cross-point. That's kinda the way my mind works, but maybe there's no value in the logic. -pmc |
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