What is H7 in hole dimension?

Answer 1

It a Standart for holes

Ex. DS 807 (Dansk Standart) v.3 Sep. 1992

Hole in mm and tolranc in µm (mikrometer)

0-3 mm = +10 to 0 µm = 3,000 to 3,010 = 3 H7

3-6 mm = +12 to 0 µm = 6,000 to 6,012 = 6 H7

6-10 mm = +15 to 0 µm = 10,000 to 10,015

10-18 mm = +18 to 0 µm = 18,000 to 18,018

18-30 mm = +21 to 0 µm = 30,000 to 30,021

30-50 mm = +25 to 0 µm = 50,000 to 50,025

50-80 mm = +30 to 0 µm = 80,000 to 80,030

80-120 mm = +35 to 0 µm = 120,000 to 120,035

120-180 mm = +40 to 0 µm = 180,000 to 180,040

180-250 mm = +46 to 0 µm = 250,000 to 250,046

250-315 mm = +52 to 0 µm = 315,000 to 315,052

315-400 mm = +57 to 0 µm = 400,000 to 400,057

400-500 mm = +63 to 0 µm = 500,000 to 500,063

OSV......

Ex. 15 mm H7 is 15,000 to 15,018 mm

Ex. 81 mm H7 is 81,000 to 81,035 mm

I don't know if the standart is the same everywhere :)

Answer 2

H7 is a tolerance class usually used for hole dimensions in mechanical engineering. It indicates a specific range of acceptable dimensions for the hole, allowing for a certain level of variation in size. In the H7 class, the hole is designed to be slightly larger than the corresponding shaft that will fit into it, ensuring proper fit and functionality.