Corbin sometimes used ball bearings in the pin stacks, as a means of minimising wear and tear on both keys and key pins in locks subjected to heavy usage. In my experience, it is often limited to the first few pin stacks in a lock, closest to the front of the keyway.
Where a standard pin stack would have a spring, a driver pin & a key pin, Corbin would have a spring, a driver pin, a key pin and then a ball bearing.
I’ve not found that the ball bearings make picking more difficult, however the Corbin locks I found them in were made to very fine tolerances, which obviously does make picking more challenging.
I suspect it is more the high-low-high-low bitting pattern in the padlock above that made it hard to pick, than the ball bearings.
I’ve never tried to impression a lock with ball bearings in the pin stacks. On one hand their shape might make them leave more subtle marks than a pointy key pin, but on the other hand ball bearings are very hard & should impress well upon the softer blank. I’d be interested to hear if they marked well or not!
…Mark
