The inner hole of the fast cheap metal grinding disc is the installation reference, and the hole diameter of the grinding wheel is unqualified and listed as “heavy defect” in the standard. When the diameter of the grinding wheel is large, the grinding wheel is eccentric after installation, which makes the fast cheap metal grinding disc unbalanced. When rotating at high speed, it will aggravate the vibration, affect the quality of the grinding process, and even cause the grinding wheel to rupture and the equipment to be damaged. If the hole diameter is too small, the grinding wheel cannot be installed and cannot be used. If it is forcibly installed, the spindle will be scratched, and the grinding wheel may be caused to be dark, which may cause the grinding wheel to break during operation and easily cause an accident. The case of the unqualified aperture is severe in the spot check. The total number of unqualified flat wheels is 16.7%, accounting for 58.2% of the total unqualified fast cheap metal grinding discs.