problem with extrude tool My skill are very limited with blender, however I need to print a tool but can't seem to make it properly on blender
This is my initial object, but I need to add a additional layer (finer) on the top so it look a bit like the second pictures :


I tried to select the edge and extrude them which seems fine and then select the faces that I just extruded and extrude them in X so it can be a few mm thick (for printing)



but that doesn't work and it make something like this

I also tried to created a duplicate of the first object and change the dimension on X/Y but it's change complete the angle of the object
Blender file
If I understand correctly what you want (?), you can:

Create an new edge loop:



Select the faces:



Extrude up: