A: Basic proficiency: 40 hours of practice. Mastery (as per Connelly’s standard): 2-3 years of full-time work.
Introduction In an age of CNC automation and high-speed machining, one might assume that the ancient craft of hand scraping has become obsolete. Nothing could be further from the truth. For industries relying on micron-level accuracy, bearing longevity, and vibration damping, machine tool reconditioning through hand scraping remains the gold standard. A: Basic proficiency: 40 hours of practice
https://archive.org/details/MachineToolReconditioning (Note: If the direct link changes, search "Machine Tool Reconditioning Connelly PDF" on archive.org) and vibration damping