A 12 mm dimension equals 1.2 cm, or approximately 0.472 inch. It is not half an inch: 1/2 inch equals 12.7 mm. These sizes should not be treated as interchangeable without checking the specified tolerances.
Define the 12 mm dimension
The description may refer to the bore, mounting-hole diameter or another feature. Identify the dimension on the drawing, then check the remaining measurements, including panel thickness, flange outside diameter and overall thickness.
Select the material
Choose the compound for the actual temperature, fluids and mechanical requirements. A nominal diameter does not establish heat resistance, durability or sealing performance.
For a custom 12 mm grommet, provide a customer drawing or existing sample with tolerances, material requirements and quantity. Manufacturability, tooling and sampling arrangements are reviewed before production.
