To assemble, you will need an M6 screw at least 25mm long with a hexagonal head and an M6 nut. It is also possible to attach a thin strip of foam to the sanding blocks, but it is not necessary.
See also:
https://www.printables.com/cs/model/788840-18mm-utility-knife
https://www.printables.com/cs/model/786337-caliper
For those of you who use honeycomb wall and want to place these sanding blocks on them, I have a holder in my models.https://www.printables.com/en/model/759143-honeycomb-holder
Here are some more interesting tools for makers.https://www.printables.com/cs/model/776080-blade-scraper-saw-handle-wire-stripper
https://www.printables.com/cs/model/757454-9mm-utility-knife
The author marked this model as their own original creation.