One gear that no gear manufacturer could repair

The 100 year old statues around Marston Hall, originally the engineering building of Iowa State University, had succumbed to the effects of acid erosion. Each statue represented a field of engineering, and the one holding the spur gear (representing mechanical engineering) was particularly badly eroded with a chipped tooth on the gear

This particular gear repair didn’t require the skills of a gear manufacturing shop but an art conservator.

The article linked here describes the process of restoration and shows a ‘before’ and ‘after’ pic of the rejuvenated mechanical engineering symbol.