some keys are designed to shear if something stops too fast so the key is damaged, and hopefully not other parts. Other keys are designed to last thru anything. There are several dimensions to a key as well as the alloys Bert mentioned. There are also straight keys. Often the terms are used interchangeably even though they are not. Need everything to align with the original if you want to be safe. You can see some differences here:
https://www.mcmaster.com/keys/key-type~woodruff/