The lockup mechanism on an S&W revolver is located at the front and rear of the extractor rod and even a slight bend can cause issues with the lockup. The Brownells yoke/crane alignment tool allows gunsmiths to align the crane more easily and precisely within minutes, eliminating any guesswork. This tool is precision-ground and hardened to within 0.0005 inches on all critical dimensions. Each tool is accompanied by comprehensive instructions. These yoke/crane alignment tools are hardened to Rc 52-54 to ensure exact specifications are maintained. The #2 alignment tool is specifically designed for use with S&W K, L and N frames.