Originally Posted by
Kstar4u
What I usually do is tack a panel of flat material (plywood or cardboard) over the space that the arch will be needed and temporarily bridge (with a straight piece of wood) the space between vertical lines that defines the arch's edge, at a point approximately halfway from the existing bottom of the opening and the existing top of the opening... level with the floor. Then I provide a pin (nail) at the middle of the vertical board to which I tie a piece of string. The string should be as long as the distance from the pin to the top opening is. Next... I tie a pencil to the other end of the string and, with the string pulled taunt...I trace the arc from one side of the space (across the top) to a point opposite where I started from. this provides a template to be used for the actual construction of the arch. You can adjust the height of you "pin" to increase or decrease the circumference of the circle (hence the radius of the curve).
Thank you for the response but what I am really attempting to do is find the actual formula
That would provide the answer every time this condition arises. I can use the
Plywood method and the string to layout a template but with as many arcs as I have to deal with, it will take forever. My on site carpenter has an autocad that can generate
Exactly what is required but I wanted this information for my own use. Thank you again for taking the time to assist... Richard