This is a remix of the popular filament cutter by 4ndreas. This is a 90° straight cut version that allows you to cut the filament while still in the printer. This is used for changing colors on the fly. The straight cut allows the chasing filament to feed better because it butts up against the old color.
It uses the end piece of a 9mm brake away type razor blade, a M3x16 screw and (I used) a 17.5 x 5.5mm spring. The mounting screw hole may need to be drilled out with a 3/32" drill bit. Screw the screw in flush with the bottom while the plunger is pressed.
There is a hole for a setscrew (just encase) that would hold the blade in place but I didn't use this.
I used support on the base for the channel.