The other day I was reading through one of the issues of "Wood Magazine" from the late 80s that was included along with my Mark 5. There was a small article about finding the center of a circle using a compass. It seemed a bit too complicated to me. This is an easy method:
Draw two straight lines that intersect the circle, but not each other (AB and CD in image below). Find the midpoint of each segment (F and G in the image below). Make another line perpendicular to the original lines at the midpoints. Where those lines intersect is the center of the circle (H in the image below).
The midpoint can be found, and a perpendicular line drawn using a compass. Open it to a distance greater than half the length of the line. From each end of the line (really called a "segment" in geometry - a "line" has no end point) make an arc on each side of the line. Draw a line through the points where the arcs intercept each other and you have a perpendicular line exactly on the midpoint of the original line.
JPG40504 wrote:Listened to the 'suite for three oranges' every sunday also! . . . . . . . . . . . . . . . . . . . . . . .The FBI in peace and war
Green Dragon. . . . The Hornet . . . Sky King . . . . Roy Rogers . . . . That explorer guy????
Does anybody remember Gabriel Heater? He had a radio news show in the 40's. I remember my grandfather listening to him on his crystal radio set, powered by an old car battery. We didn't have electricity out in the country then.
heathicus wrote:The other day I was reading through one of the issues of "Wood Magazine" from the late 80s that was included along with my Mark 5. There was a small article about finding the center of a circle using a compass. It seemed a bit too complicated to me. This is an easy method:
Draw two straight lines that intersect the circle, but not each other (AB and CD in image below). Find the midpoint of each segment (F and G in the image below). Make another line perpendicular to the original lines at the midpoints. Where those lines intersect is the center of the circle (H in the image below).
The midpoint can be found, and a perpendicular line drawn using a compass. Open it to a distance greater than half the length of the line. From each end of the line (really called a "segment" in geometry - a "line" has no end point) make an arc on each side of the line. Draw a line through the points where the arcs intercept each other and you have a perpendicular line exactly on the midpoint of the original line.
Looks like the compass/ruler method(better than compass only, no approximation at all).
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
I'm too young to have listened to the original broadcasts, but I'm a big fan of old radio dramas. I have a box of cassette tapes at home of The Shadow, Superman, Lone Ranger, Green Hornet, etc.
curiousgeorge wrote:Does anybody remember Gabriel Heater? He had a radio news show in the 40's. I remember my grandfather listening to him on his crystal radio set, powered by an old car battery. We didn't have electricity out in the country then.
What was the battery for on the 'Crystal set'?
Yes I remember 'Gabriel'. Ed Morrow also. And Ted Grizzard(he was Local!).
Believe it or not I listened to many of these on MY crystal radio receiver(purchased the crystal and cat whisker and made the rest[not the earphone]). Long wire antenna a must!
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
Heathicus drew up the method! This is used by archiaologists to find the actual size of a pot or bowl from a shard of pottery. By simply drawing the outline of the shard on paper and using this method to locate the center , the diameter can be found. I listened to Gabrial on the radio in my grandpas dairy barn.
Yes I remember all of the radio shows mentioned and the crystal set radio was my first radio. I remember living in Denver and climbing to the top of my parents fireplace flue and twisting the antenna in a variety of directions. The farthest radio station I could pick up was in Nashville. I am still addicted to Country Music and the Grand Ole Oprey. Jim
F. Jim Parks
Lakewood, Colorado:)
When the love of power is replaced by the power of love the world will have a chance for survival.
heathicus wrote:I'm too young to have listened to the original broadcasts, but I'm a big fan of old radio dramas. I have a box of cassette tapes at home of The Shadow, Superman, Lone Ranger, Green Hornet, etc.
Then there was "Bobby Benson and the B Bar B Riders" and "Challenge of the Yukon" with Sergeant Preston and his faithful dog Yukon King.
These were all programs that we listened to after getting home from school and before supper was placed on the table. These kept me out of trouble.
There was a mystery program that played later in the evening, sponsored by Pall Mall cigarettes, that I wasn't suppose to listen to but I did. Don't remember the name anymore.
"Making Sawdust Safely" Dusty
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I came home tonight and found the instructions in "Wood Magazine" for finding the center of a circle. My scanner is broke, so I can't scan the page. I don't have a decent image editing program on the tablet PC I'm using, so I just sketched it out real quick in Paint. The instructions below are re-typed as they appear in the magazine (not as complicated as I was thinking it was!):
From any two points (A) on the circumference, use trammel points to mark equidistant points (B and C) on both sides of both starting points. Then open up the distance on your trammel points a bit, and arc from each of the second pair of points (B and C) to determine two interior points (D and E). Use a straightedge to connect your two starting points (A) with the interior points (D and E). Now you have it: The center (F) will be the point where those two lines (A-D and A-E) meet.
