Filament Sharpener

I needed a filament sharpener but did not have any spare pencil sharpeners I could convert, so I designed my own that would use two utility knife-blade segments that I had handy.

THIS IS A WORK IN PROGRESS - THE BLADE ALIGNMENT AND RETENTION IS INCOMPLETE AND FIDDLEY
PLEASE HELP IMPROVE IT AND/OR MERGE WITH A FILAMENT CUTTER DESIGN FOR THE ALL-IN-ONE-TOOL WIN!

Now with the shouting from the rooftops out of the way ;) on with the details...

My first iteration was the smaller rectangular block. I printed it at 0.1mm blade clearance and the blade was a super tight fit, I ended up using Knipex pliers to press the blade in and get it perfectly halfway into the filament channel.

BLADE ALIGNMENT IS CRITICAL

Turns out the tightness was in-part due to the smaller print being warmer and less accurate.
When I decided to do the round version of the sharpener, I expanded the blade slot to 0.2mm clearance.

It printed great, and may be a good clearance, but it also may be a little loose.
To i