2. Knowing the outer package or inner diameter of this shape and the thickness of the edge, you can draw two concentric circles with the same point as the center according to the method of drawing circles, and take half to use.
3. The distance between gardens is the thickness of the edge of this model.
Woodworking circular arc template method: 1. First of all, we need to choose a small curvature wooden formwork, including the first formwork unit and the second formwork unit, and then connect the two formwork units through the first pair of opposite bolts; Then, the wood plywood and the round steel pipe are sequentially placed from inside to outside, both of which are arc-shaped, and a first wood square is placed between the wood plywood and the round steel pipe at equal intervals; 2. Then we need to fasten the two templates directly with bolts; Then the periphery is reinforced with a super 3.2cm wide steel belt, and it can be tightened directly with screws. 3, in the periphery of the template vertical four wood square, and then horizontal every one meter interval with steel pipe to play a derrick, this purpose is to strengthen the template, but also to better ensure the construction safety.