A larger knob with 100 markings making your dialing process much easier.

Use double-sided tape to attach the arrow to the grinder body.

warning: Use KnobWithTolerances.stl model if you printing with FDM printer. You still might need a bit of force to put the model on the original knob.

Also, you can adjust the knob size and markings lengths using the OpenSCAD file included, just change the parameters, render and export STL.