J21S series of press machine deepens the throat, and its throat depth is four times of that of common machine. The J21S series has large work space, and it can finish the forming in one punch without turning around. It is widely used for the machining of large size plates, and all the J21S series adopt steel plates welded machine body with high strength and rigidness, and adopt the rigid rotating key type clutch which is convenient to operate and service, the machine has reliable performance and works smoothly.