12" Atlas / Craftsman Back-Gear Lock

thingiverse

When removing the chuck from Atlas / Craftsman lathes, it seems that people lock the back-gear and then wrench on it. Problem is that this puts all the torque on one small pin, which can shear off. By using this lock on the main back-gear, you no longer have to lock the rear back-gear, and instead lock the gear across multiple teeth and then into the casting of the machine itself and no torque is ever transmitted via the small pin.