- #1
guyburns
- 32
- 7
I am putting in a new flue for a Pot Belly stove. The ceiling through which the flue goes slopes at 12.5º. I want to cut a hole in a metal plate that will be fixed to the ceiling, and through which the flue passes.
So, a vertical circular flue, radius R, passing through a ceiling sloped at 12.5º to the horizontal.
How do I get the shape of the hole? I assume it is going to be an ellipse with short axis A, long axis B, where:
A = R
B = R/Cos (12.5º)
My thinking is to:
1. Generate a circle of Radius R in Photoshop.
2. Transform (stretch) the circle horizontally by 1/Cos(12.5º). It becomes an ellipse.
3. Print the result, lay it on top of the sheet metal, punch a few holes as markers, then cut it out.
Is the mathematical part of the above correct?
So, a vertical circular flue, radius R, passing through a ceiling sloped at 12.5º to the horizontal.
How do I get the shape of the hole? I assume it is going to be an ellipse with short axis A, long axis B, where:
A = R
B = R/Cos (12.5º)
My thinking is to:
1. Generate a circle of Radius R in Photoshop.
2. Transform (stretch) the circle horizontally by 1/Cos(12.5º). It becomes an ellipse.
3. Print the result, lay it on top of the sheet metal, punch a few holes as markers, then cut it out.
Is the mathematical part of the above correct?