cadquery is similar to OpenSCAD, just in python and using a different CAD core.
Basically, instead of using a GUI to draw and construct your models, you use code to describe them. Since I am a software developer, it was easy for me to get into and now I get better results quicker with cadquery than with FreeCAD, so I will stick to it.
https://cadquery.readthedocs.io/en/latest/quickstart.html#quickstart
> Do you have anything to recommend over OpenScad that's free to download?
You can try cadquery, I have only messed with it a little bit but seems promising. It has concepts of the edges and surfaces so you can add fillets and chamfers easily. It uses Python as its language.
It is a little harder to get started with if you aren’t familiar with conda and/or the Python ecosystem. If you are already familiar with conda though it should be a breeze:
Gee, I'm late but was cutBlind what you were looking for?
https://cadquery.readthedocs.io/en/latest/classreference.html#cadquery.Workplane.cutBlind
Basically just draw a circle with the pocket radius followed by cutBlind.
Alternatively (and probably faster!) is to first extrude the cylinder to the bottom of the pocket, then draw two more circles (outer radius and pocket radius, forming a ring) and extrude that to the top height.