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 :)