"Don't lift by the handle" is an oft repeated phrase. Sometimes the nuts that hold it on are about ready to drop. Rarely but sometimes the wood is actually weak enough to let go. Key slots can be just a slit, a triangle or a square.
But as Janey said, a little screwdriver can usually get it open. I also use my awl blade on my Swiss army knife sometimes. Our traveling machines have tags on each on telling us what key to use .
Last edited by leonf; 12-04-2019 at 11:35 AM.