Clearances For Metric Bolts (mm)

	Hole Size	Diameter of Square drive Socket	Diameter of ring spanner
M3	3.4	14	-
M4	4.5	22	14
M5	5.5	22	14
M6	6.6	26	17
M8	9	26	22
M10	11	27	27
M12	13.5	29	30
M16	17.5	42	38
M20	22	47	46
M24	26	54	55
M30	33	70	70
M36	39	81	90