As usual, I searched the internet for a file handle but didn't find any that looked right, felt comfortable or fitted the file, so I designed my own in DesignSpark Mechanical.

I printed this in PLA adding an extra perimeter and increasing fill density.

If you want this for a smaller file you can scale the stl or modify the design with the RSDOC

Use the enclosed the RSDOC file if you want to customise it to your needs.