Calculate with trigonometric function. Look up the math table to get the result. If the angle is not greater than 10, you can subtract the diameter of the small end from the diameter of the big end, divide the result by the length of the big end to the small end, and then multiply it by 28.7, and finally get the half cone angle.

1 、( D 1-D2)/Lx28.7 .

2、 ? D 1: big end diameter.

3、 ? D2: small end diameter.

4、L:？ Length.

Example:

1:5 means that if you move 5 mm along the axis of the cone, the diameter will change1mm. The radius will change by 0.5 mm

Using a right triangle, the cone half angle can be calculated. Let the cone angle be θ, then the cone half angle is θ/2.

Tan(θ/2)=0.5/5=0. 1, so θ/2=arc tan0. 1.

Find the inverse function θ/2 = 5.7 10593 = 5 42' 38 "with a calculator.

Cone angle θ =11.421186275 =1125'16 "