Recommended Tap Drill Sizes 螺紋下孔徑對照表 - …

1 Unit: mmMin. Max. Min. Max. Min. Max. M1 ( )( )M10 ( )( )M10 ( )( )M10 ( )( )M10 ( )( )M10 ( )( )M11 ( )( )M11 ( )( )M11 ( )( )M12 ( )( )M12 ( )( )M14 ( )( )M15 The Recommended tap Drill Sizes indicated above are for JIS 6H (Class 2) Metric Threads. D1: Minor diameter of JIS 6H (Class 2) internal thread. The Minor diameters D1 shown in ( ) are of 5H (Class 2) for coarse threads and of 4H 5H (Class 1) for fine Tap Drill Sizes Nominal size Drill size JIS 6H Class II Drill size JIS 6H Class II JIS 6H Class II Nominal size Drill size Nominal size Metric Metric Metric Unit: mmNominal size Drill size Min.

2 Max. Nominal size Drill size Min. Max. Nominal size Drill size Min. Max. No. 1 0 2 1 3 2 4 3 5 4 6 5 8 6 8 1/8 1/4 3/8 1/2 1/8 UN 8 UNC 1/4 UN 8 UNC 3/8 UN 8 1/8 UNC 1/2 UN 8 1/4 UNC 1/8 5/8 UN 8 3/8 UNC 1/4 5/8 1/2 UNC 3/8 3/4 UN 8 3/4 UNC 1/2 3/4 UNC 4 UN 8 PT 281/8 PT 281/4 PT 193/8 PT 191/2 PT 143/4 PT 141 PT 111-1/4 PT 111-1/2 PT 112 PT 11 Internal Thread Minor Dia. on[Min.] Gauge Length Pipe Thread (PT) RcRecommended Tap Drill Sizes UNEF, UN UNF UNC Nominal size With Reamering Before Tapping Without Reamering Before Tapping Drill size Internal Thread Minor Dia.

3 On[Min.] Length of Useful Thread The Recommended tap Drill Sizes indicated above are for JIS Class 2B UNC & UNF threads, and ANSI Class 2B UNEF, UN & UNS threads. D1: Minor diameter of internal thread. For UNC and UNF threads, according to JIS Class 2B; For UNEF, UN and UNS threads, according to ANSI Class : mmMin. Max. 1/8 W PS SM W PS SM W PS SM W PS W PS SM W PS SM W PS SM W PS SM W PS SM W PS SM W 9 SM W 8 SM W 7 SM W 7 SM W 6 SM W 6 PF SM W 5 PF SM W 5 PF SM W 4 PF SM W 4 PF SM W 4 PF SM W 4 PF SM W 3 PF SM 3 W 3 PF SM PF SM PF SM PF SM PF SM PF SM - ( )1/8 - ( )1/4 - ( )3/8 - ( )1/2 - ( )3/4 - ( )1 - 11 ( )1 - 11 1 - 11 2 - 11 2 - The Recommended tap Drill Sizes indicated above are for JIS Class 2 Whitworth Threads.

4 D1: Minor diameter of JIS Class 2 internal thread. Whitworth Threads have been eliminated from JIS. The Drill Sizes are according to ANSI/ASME PIPE THREADS, GENERAL PURPOSE (INCH) (partial listing). The Drill Sizes are according to ANSI Dryseal Pipe Threads (Inch) (partial listing). Marked Sizes are in accordance with Standard Pipe Thread Dryseal American Standard Pipe ThreadNominal size size Drill size Drill size With Reamering Before Tapping Without Reamering Before Tapping NPTNPSD rill size Reamering Before Tapping Without Reamering Before Tapping Recommended Tap Drill Sizes Nominal size Drill size Drill size Class II ThraedNominal size Drill size Nominal size Sewing Machine Threads Pipe Thread (PS) Rp Whitworth Coarse Threads Min.

5 Min. Max. Max. Nominal size Drill size A, B Class ThreadPipe Thread (PF) G Metric Screw Threads Unit: mmR limits R limits M x ~ (100~80) ~ (100~75)M x ~ (100~80) ~ (100~75)M 3 x ~ (100~80) ~ (100~75)M x ~ (100~85) ~ (100~75)M 4 x ~ (100~85) ~ (100~85)M 5 x ~ (100~85) ~ (100~80)M 6 x ~ (100~85) ~ (100~80)M 7 x ~ (100~85) ~ (100~80)M 8 x ~ (100~85) ~ (100~85)M 8 x ~ (100~85) ~ (100~80)M 10 x ~ (100~90) ~ (100~85)M 10 x ~ (100~85) ~ (100~85)M 10 x ~ (100~85) ~ (100~80)M 12 x ~ (100~90) ~ (100~85)M 12 x ~ (100~90) ~ (100~85)M 12 x ~ (100~85) ~ (100~85)M 12 x ~ (100~85) ~ (100~80)M 14 x ~ (100~90) ~ (100~85)M 14 x ~ (100~90) ~ (100~85)M 16 x ~ (100~90) ~ (100~85)M 16 x ~ (100~90) ~ (100~80)

6 M 18 x ~ (100~90) ~ (100~85)M 18 x ~ (100~90) ~ (100~85)M 20 x ~ (100~90) ~ (100~85)M 20 x ~ (100~90) ~ (100~85)Unified Screw Threads R limits R limits ~ (100~70) ~ (100~70) ~ (100~70) ~ (100~70) ~ (100~75) ~ (100~75) ~ (100~75) ~ (100~70) ~ (100~75) ~ (100~75) ~ (100~75) ~ (100~75) ~ (100~80) ~ (100~80) ~ (100~80) ~ (100~80) ~ (100~85) ~ (100~80) ~ (100~80) ~ (100~80)1 ~ (100~80) ~ (100~80)1 ~ (100~80) ~ (100~80)5 ~ (100~85) ~ (100~80)5 ~ (100~85) ~ (100~80)3 ~ (100~85) ~ (100~80)3 ~ (100~85) ~ (100~80)7 ~ (100~85) ~ (100~80)7 ~ (100~85) ~ (100~80)1 ~ (100~90) ~ (100~80)1 ~ (100~90) ~ (100~80)9 ~ (100~85) ~ (100~85)9 ~ (100~90) ~ (100~80)5 ~ (100~90) ~ (100~85)5/8-18 ~ (100~90) ~ (100~80)3 ~ (100~90) ~ (100~80)3 ~ (100~90) ~ (100~85)7 ~ (100~90) ~ (100~85)7 ~ (100~95) ~ (100~85)1" ~ (100~90) ~ (100~85)1" ~ (100~90) ~ (100~85) Recommended Tap Drill Sizes For Fluteless Taps (CRT) JIS Class 1 Drill Hole Dia 1 JIS Class 2 Drill Hole Dia 2 Min~Max (thread overlap%) ~ JIS 3B Class Drill Hole Dia 3B JIS 2B Class Drill Hole Dia 2B Nominal size Min~Max (thread overlap%) ~ Nominal size Min~Max (thread overlap%) ~ Min~Max (thread overlap%) ~