Finding circle center

F

Frank Skufca

Joined
Nov 1, 2002
Messages
4
This is a duuhhh...

Forgot how to find the center of a circle. I have a 1 inch pommel and need to drill a hole in the center.

Anyone remember how to find the center of a circle from their high school geometry?

Frank Skufca
fskufca@utech.net
 
Well, pi = Circumference/diameter. And since the radius is 1/2 of the diameter then it should follow: Measure the circumference divided by 3.1412, then divide that total by 2 to get the radius.

Measure the radius from any point from the circumference at a 90 degree tangent and you should have the center.

Ahh, that's too much work. Just "eye" it!

FTC

Okay, okay, I admit I suck at geometry...Stupid Pythagorus and all that crap!
 
take a caliper, measure the diameter, divide by two, and put a ruler perpendicular to the "prongs" of the calipers, and measure the radius at the point that one of the prong touches at the circle. This line should eventually lead to the other prong perpendicularly.
It's kinda hard to visualize, isn't it?
 
If its a true circle just take a straight edge, holding one edge firmly rotate it till you get the largest diameter, at that point draw a line...do it again approximately 90 degrees from the current line. Where the lines intersect should be the center. To make sure do another line 45 degrees (inbetween) the other two, it should intersect at the same point, if not you were a little off.
 
To find exact center of any circle, take a compass, and place the sharp end somwhere on the circle, then make an arc inside the circle just past half way . now do the same thing from another point on the circle, near the opposite side somewhere works best. Now, draw a line through the points where the two arc's intersect, extending across the circle in either direction. This line will exactly bisect your circle, crossing the circle at two points that are perfectly 180degrees apart and passing through the center of your circle. Repeat this process puting the sharp point of the compass, on the two points where the new line you drew crosses the circle. The point at wich the two straight lines intersect, will be the exact center of the circle. Now see, I did manage to stay awake during at least one of my highschool geometry classes! JDBraddy
 
I agree JD pegged it.
 
Heh heh, I saw the title and thought you were trying to find the mall in Indianapolis, IN. :D
 
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