This is a model for a toy Gravity Knife. Just like on a real gravity knife, the handle is in two parts and the blade slides up and down out the top.

Set models between 33-36% scale in slicer for best tolerances and size. I printed mine on an Ender 3 at 34% scale. It can all be printed without supports if you print the blade vertically, but then the blade could snap off easily so I printed mine with supports, with the blade at a 15 degree angle from the print bed. You also have to carefully bend the 2nd handle piece to get it to fit around the pin on the first handle piece.

The blade doesn't slide smooth at first but gets looser after a bit of use, Hope you like it!