http://www.tobias-elze.de/pdfsandwich/ has been my tool for years to OCR old research papers and books. It uses Tesseract and some other tools to get the job done.

It's last in my workflow after using:

Briss, a simple cross-platform application for cropping PDF files: https://sourceforge.net/projects/briss/

PDF Arranger to merge or split pdf documents and rotate, crop and rearrange their pages using an interactive and intuitive graphical interface: https://github.com/pdfarranger/pdfarranger