Did you turn do final turning after after hardening due to possible dimensional changes from heat or surface finish or both? I've read many 4140 parts put into service without tempering and this looks like such an application.
@cyrildanko842211 ай бұрын
Part was also tempered, but unfortunately that's not captured in the video. I always leave some material before HT, finished part should be machined on cylindrical grinder for best tolerances.