>>6145487The way they fit together, you would think they don't stay put.
I'll simply say this : You need pliers to attach or detach them, they're 100% solid. It's a lot different than a normal sort of spinning chuck style fastener from Xacto but I assure you it's no less tight.
Once you get used to the profile of a flat blade, you will never go back. Having a new blade every day is the bee's knees. If you know how to fiddle with heatshrink, build the handle up with a few layers or add tape so it's not so thin in your hand and it'll be easy as pie.
I've cut myself a lot more with these than Xacto, the sharpness is crazy.