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BP0005 Circle Division
by Bill Epps
Diameter x factor = cord length
Table 1. Bill Epps
These numbers are confirmed in the Machinery's Handbook 12 th ed. page #75
Calculate or measure the circumference of a circle. Divide that distance by the number of segments and then measure directly onto the pipe or whatever circular form on which you are working.
Brake drums have 4, 5, 6, 8, etc pattern bolt holes. They are metal and also have the advantage of being able to weld to them.
First draw a circle that will give you an even number for the divisions, example 5 parts 10 inches
Draw a line 10 inches long and mark at 2 in intervals, then mark the center at 5 inches
Draw a circle 10 inches in diameter using the center 5 in mark
Set the compass for the diameter and scribe a line at the bottom below the circle from each side, so the the lines cross
Use a ruler and draw a line from the crossed lines at the bottom thru the second line on the diameter, where this line crosses the circle is 1/5 of the circumfrence,
If you want 13 segments, or 9 or 17 or any number, do the same thing always thru the second mark from one edge on the diameter. Irnsrgn
BP0005 - Circle Division