Though I found some cutter knifes (also called Stanley Cutter) to download for 18mm blades, I realized, that each had another problem. One was too short to cover a full length blade completely, the other one was too weak, some had only a slot, sometimes the holes were at a wrong position, some had a very small bolt and others had very sharp and uncomfortable edges. Another important part for me was, that I also needed a knife for 22mm and 25mm blades. For 22mm I didn't find any, and I couldn't scale the found ones correctly :-(

So I decided to design these myself, where I could change every part as needed ;-)

This is my version for 22mm blades with breaking points 10mm apart. You'll need either the body with separate holes, or the body with a slot. The slot version should fit every available blade. The version with separated holes will be better, if You often push against the knife (as my son often needs to ;-) ). The blade will be fixed securely, contrary to the slot version, that may not be fixed enough and will slide the blade back!

The fixation and bolt fits for both bodies.

Here You will also find my version for 18mm and 25mm blades:
https://www.thingiverse.com/thing:6652615
https://www.thingiverse.com/thing:6653125

UPDATE on 14/06/2024:

After the user dhp73 called his design
https://www.thingiverse.com/thing:3788426 "Stanley Cutter", I assumed that this was an original design by Stanley and so I only used the form as a basis for my own design. The user Hevizizs81 pointed out to me that this design was actually made by dhp73 and did not really correspond to the original Stanley cutters. So the credit should go to dhp73.

UPDATE on 08/07/2024:
The user baiacu pointed out, that he was the first with the idea of hard stop holes. So please also give credit to his design:
https://www.thingiverse.com/thing:6614380