Bored hole size before tapping ( for thread forming )

■ for Metric Threads

Unit : mm

SizeClassBored Hole SizeExpected minor Diameter of Internal Thread Size
M1×025G40.91076
.G50.92.
M12×025G41.11096
..G51.12.
M1.4×0.3G4 G51.28 1.301.12
M1.4×0.2G31.321.21
G41.46
M1.6×0.35G51.471.28
G61.48
M1.6×0.2G31.521.41
G41.56
※M1.7×0.35G51.571.38
G61.58
M18×035G41.66148
..G51.67.
G41.82
M2×0.4G51.831.64
G61.85
M2×025G41.90176
.G51.92.
M2.2×0.45G52.011.79
G42.12
※M2.3×0.4G52.131.94
G62.15
M25×045G52.31209
..G62.33.
M25×035G42.35218
..G52.37.
※M26×045G52.41219
..G62.43.
※M26×035G52.47228
..G62.48.
G52.79
M3×05G62.81255
.G72.82.
G82.83
M3×0.35G52.852.68
G62.87
G53.24
M3.5×0.6G63.252.95
G73.26
M35×035G53.35318
..G63.36.
G53.69
M4×07G63.70335
.G73.72.
G83.73
SizeClassBored Hole SizeExpected minor Diameter of Internal Thread Size
G53.79
M4×0.5G63.803.55
G73.82
G54.63
M5×08G64.65426
.G74.66.
G84.67
M5×05G64.80455
.G74.81.
G55.53
M6×1G65.55506
G75.56.
G85.57
M6×075G65.67531
.G75.68.
※M6×0.5G65.795.55
G66.54
M7×1G76.566.06
M7×0.75G76.686.31
M8×125G77.44681
.G87.45.
M8×1G77.557.06
M8×0.75G77.687.31
M10×1.5G7 G89.31 9.338.56
M10×125G79.44881
.G89.45.
M10×1G79.559.06
M12×1.75G8 G911.20 11.2110.32
M12×1.5G811.3110.56
G911.32
M12×125G811.431081
.G911.45.
M12×1G711.5511.06
M14×2G913.081207
G1013.10.
M14×1.5G913.3212.56
M14×1G813.5513.06
M16×2G9 G1015.08 15.0914.07
M16×1.5G915.3114.56
M16×1G815.5515.06
M18×15G917.311656
.G1017.32.
M20×2.5G1118.8617.58
M20×1.5G9 G1019.31 19.3218.56

Sizes with * mark are deleted from JIS. Technical Inf