Very small Switchblade/knife (keychain?)

Made a small keychain-like switchblade that uses only one segment from an **18mm** utility knife. Due to this, only a small part of the blade can be used, rendering it less effective depending on the context.
The joint is supposed to be either glued or soldered/melted to the outer case.
If the blade is too loose/tight you might want to decrease/increase tolerances accordingly. I've uploaded the .blend file to make that easier. A graphite pencil can also be used to decrease friction with the joint.