The original design used a Xacto blade (https://www.printables.com/model/432329-x-acto-letter-opener).
The advantage is that the blade is pretty small. I wanted to use a part (3 break-off pieces) of a standard small hobby knife. (In German "Japanmesser").
My first published design I noticed that it does not work well under all circumstances because the angle of the blade is too steep. I modified the design to have a lower angle. Unfortunately to get a workable design I had to make the body longer.
I also checked out an existing commercial model I had, and copied the little “arc” that is supposed to hold the paper down.
So far it seems to work better.
I printed with an MK4S with 0.4HS Nozzle with 1.5 layer structural.
In the 3mf file I added a pause where you have to put in the blade. Be sure that the blade is down completely and oriented correctly.
To be sure I carefully used a very small drop of superglue to hold the blade in place when the printing continues.
When you want to change the design I added the F3D files. Be aware I am not a trained mechanical designer, and designed this “by the seat of my pants”.
Have fun, and when you print and/or modify it please share your results.
The author remixed this model.
Improved the design Better angle of the blade