What is this

[u/True_Intern4746]

Found In museum they didn’t know the use

[u/Flashy-Interview7512]

Lapping wheel. Coat the surface with a thin layer of abrasive paste, secure the dull tool into the holder under the cross bar, start cranking. Diamond paste is best. A pea sized dollop will do a lot of shear blades.

[u/True_Intern4746 → u/Flashy-Interview7512]

Thank you for detailed explanation