1. ## coping cutting help

How does one calculate how much to cut to form a radius when cutting coping stone. My pool has 7' and 5' radius and there probably is a formula how much needs to be cut on both sides, but I cannot find it. Any help would be appreciated.

2. ## Re: coping cutting help

Got a pic? a 7' radius can be interpreted different ways. Is the curve constant?

4. ## Re: coping cutting help

1. A circle with a 7' radius has a circumference of 44' (close enough, anyway)

2. Measure the partial circumference of the curve at the top of the pool.....let's guess it to be 26 feet

3. 26/44= .59 of a full circle.......so, 360 degrees/.59 = 212 degrees

4. If your coping tile is one foot, it will take 26 tiles to complete this curve. Then divide the 212 degrees by 26 tiles and get approx 8 degrees per tile.

5. 8 degrees per tile would be 4 degree cuts on each side of the tile.

6. Grout will have to be considered so your total tile length may be 12.25"

7. That won't be perfect but probably as perfect as you can do with a tile cutter.......it'll look good.

There might be a formula but I don't know it.

5. ## Re: coping cutting help

You're welcome.

6. ## Re: coping cutting help

Oh, sure you are more then welcome. I appreciate the help. Posted a reply but for some reason did not show up. I also came up with a same angle, but using different approach and little more complicated, but confirms you angle

Circumference of the circle is 43.98, let's round it up to 44. Since I want the tiles at the end not to be cut, and there will be overhand of 1", outer circle radius is 84 + 17 = 101. So outer circle circumference is 52.88', lets round it up to 53'. So basically inner circle is 9 feet shorter then outer one. Inner circle due to gap of 1/4" between tiles can hold only 43 tiles. So from these 43 tiles I have to take away 9'. 9x12 = 108/43 = 2.51. So from each tile I have to take away 2.5 inches, so on each side that is 1.25". Now if we apply trigonometry, since we know all the pieces we can calculate the angle of the cut. Based on opposite and adjacent side length, angle on the top of the tile is 3.97 degrees.

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