All the parts are designed so that no post-processing is needed (removing supports, sanding...) and no external parts are needed (except for the belts).
Happy printing

This mechanism is a modification of No. 9, the pulleys being of different shape.
Other mechanisms from this same book
The official website of this book
I would really appreciate if you leave a like to this model so I can continue making many more 3D models like this one.
The author marked this model as their own original creation.