Folder consist nine models, each seperated in exported files. The whole scene as seen on the rendered images is in .blend file. They are subdivided with lvl2 subdivision modifier. Models are named and sorted in a way that moving them in your scene will not give you a hedache. Median points are at the base of Knob Base. Also I have parented them to the base but it is easy to switch base and handles. Scene is sorted and every knob is at its own collection(layer).
I'm also uploading blender file that consists all the textures and materials that I have used in the rendered images. Although I recommend to apply your own materials. I am sure that this can look much better, meshes have nice detail and this gives nice looking style. Top this with better materials and it will look fantastic.
Thanks for viewing my models. If you have any questions, comments, recuests, please do.