Tool bit for turning ladder at outer edge of metal circular ring

The utility model discloses a tool bit for turning a ladder at the outer edge of a metal circular ring. The tool bit comprises a fixing column, wherein the front end of the fixing column is of a triangular shape, a notch is formed in the side edge of the front end of the fixing column, double tool bit bodies are installed in the notch in a clamped mode, the double tool bit bodies are both of triangular shapes, one of the double tool bit bodies is large, the other of the double bit bodies is small, a rotating pressure block is installed at the edge of the notch of the fixing column, and the rotating pressure block is fastened on the fixing column through a bolt; the rotating pressure block is fastened on the fixing column through the bolt, and the bolt can be screwed up to enable the rotating pressure block to be loosened when the tool bit needs to be replaced. According to the tool bit, the structure of the double tool bit bodies is installed on the fixing column through a compressing device, the tool bit is