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Metric Size (Diameter x Pitch) Approximate Imperial Equivalent Imperial Size (Diameter x Threads per Inch) Approximate Metric Equivalent
M2 x 0.4 1/16" #0-80 (0.060") x 80 TPI M1.6 x 0.35
M3 x 0.5 1/8" #4-40 (0.112") x 40 TPI M2.5 x 0.45
M4 x 0.7 5/32" #6-32 (0.138") x 32 TPI M3.5 x 0.6
M5 x 0.8 3/16" #8-32 (0.164") x 32 TPI M4 x 0.7
M6 x 1.0 1/4" #10-24 (0.190") x 24 TPI M5 x 0.8
M8 x 1.25 5/16" 1/4"-20 (0.250") x 20 TPI M6 x 1.0
M10 x 1.5 3/8" 5/16"-18 (0.3125") x 18 TPI M8 x 1.25
M12 x 1.75 1/2" 3/8"-16 (0.375") x 16 TPI M10 x 1.5
M16 x 2.0 5/8" 1/2"-13 (0.500") x 13 TPI M12 x 1.75
M20 x 2.5 3/4" 5/8"-11 (0.625") x 11 TPI M16 x 2.0
M24 x 3.0 1" 3/4"-10 (0.750") x 10 TPI M20 x 2.5