Master LOTO locks make great practice locks. But they have a weakness in that if you turn the picked core too far, all of the key pins fall out and you end up with a plastic rattle.
Go ahead, take out your frustration.
At least you can recover the core. But now you need to use a vise and the picking isn’t nearly as convenient.
But if you have (or know someone who has) a 3D printer, you can have your nice practice lock back. I found a great model on Thingiverse (I didn’t make it, I am just endorsing it).
https://www.thingiverse.com/thing:1134059
Printed it looks like this:
Just drop in your recovered parts and screw it together.
There is only one part, so you print two. The holes are round, but if you put a nut on a bolt, grip the bolt with vise grips, and hold it in a torch for a second, you can turn one side into a nice custom fit hex.
It works really well.
David
