A method is disclosed for reducing the variance in the coolant consumption of components of a turbo-machine, in particular a gas turbine. The components are provided with one or more holes for the passage of a coolant, wherein a surface roughness existing inside the holes is reduced by mechanical finishing. The method is characterized by mechanical finishing that is performed by reshaping rough points that cause the surface roughness using a cold working process such as at least one of beating, pressing and rolling. The method permits a simple reduction of the surface roughness without creating finishing residues that could result in obstructions of the holes.