7 New Clock Hole Closing Punches. This is a new set of 7 clock hole closing punches. These are for reducing hole sizes in brass plates in clocks, meters, etc. Spring center guides punch so that it will be concentric. Punches are tapped with a small hammer. Size 1/0, 2 mm. Size 1, 2.1 mm. Size 2 , 2.6 mm. Size 3, 3 mm. Size 4, 3.5 mm. Size 5, 4.1 mm. Size 6, 4.6 mm.