If you Google “slow speed handpiece repair” or “slow speed handpiece threads stripped” companies will come up that can repair them. I believe Henry Schein may even have a repair service. However, there are much more ergonomic handpieces that have come out within the last 8 years so it might not be a bad idea to invest in a new one. Do remember that the CDC requires slow speeds to be heat sterilized in between patients (not just surface disinfected) so getting the stripped handpiece repaired for a back up (like if sterile runs behind) may be a good idea too.