建議下孔徑
Recommended Tap Drill Sizes
◎ 公製牙
● D1：
●Minor diameter of JIS Class 2 internal thread.
But, the minor diameters D1 shown in ( ) are of JIS Class I internal threads because their nominal sizes are not specified in JIS Class 2. ● * Marked sizes have been eliminated from JIS since 1969.
◎ 公製牙
● D1：
● The reccommended tap drill sizes indicated above are for JIS Class 2 Metric threads.
Minor diameter of JIS Class 2 internal thread.
But, the minor diameters D1 shown in ( ) are of JIS Class I internal threads because their nominal sizes are not specified in JIS Class 2.
◎ 美製牙 ─ UNC，UNF
● The recommended tap drill sizes indicated above are for JIS Class 2B UNC & UNF
threads, and ANSI BI . Ia Class 2B UNEF & UN threads. ● D1：Minor diameter of internal thread.
For UNC and UNF threads, according to JIS Class 2B;
For UNEF and UN threads, according to ANSI BI . Ia, Class 2B.
◎ 英製牙 ─ BSW
● The recommended tap drill sizes indicated above are for JIS Class 2 Whitworth
threads.
● Generally, the tap drill sizes in column A are used for producing holes; When holes tend to be cut oversized, the tap drill sizes in column B should be selected. ● These tap drill sizes are in accordance with JIS B 1004-1966, while the nominal sizes
with a * mark are in accordance with BSW (Please refer to page 135).
◎ 管牙
●-1982
●●
0203-1982 Rp internal thread.
0203-1982 G internal thread.
The reccommended tap drill sizes indicated above are for JIS Class A PF threads.
◎ 管牙
● *1The above drill sizes are according to ANSI/ASME BI.20.1-1983 Pipe Threads,
General Purpose (inch) (partial listing).
● *2The above drill sizes are according to ANSI/ASME BI.20.3-1976 Pipe
Threads,
(inch) (partial listing).
◎ For Threads Using with Helical Coil Wire inserts
insert
manufacturers.
● The figures listed above are according to the data provided by helical coil wire
◎ 無溝絲攻下孔徑
建議下孔徑
Recommended Tap Drill Sizes
◎ 公製牙
● D1：
●Minor diameter of JIS Class 2 internal thread.
But, the minor diameters D1 shown in ( ) are of JIS Class I internal threads because their nominal sizes are not specified in JIS Class 2. ● * Marked sizes have been eliminated from JIS since 1969.
◎ 公製牙
● D1：
● The reccommended tap drill sizes indicated above are for JIS Class 2 Metric threads.
Minor diameter of JIS Class 2 internal thread.
But, the minor diameters D1 shown in ( ) are of JIS Class I internal threads because their nominal sizes are not specified in JIS Class 2.
◎ 美製牙 ─ UNC，UNF
● The recommended tap drill sizes indicated above are for JIS Class 2B UNC & UNF
threads, and ANSI BI . Ia Class 2B UNEF & UN threads. ● D1：Minor diameter of internal thread.
For UNC and UNF threads, according to JIS Class 2B;
For UNEF and UN threads, according to ANSI BI . Ia, Class 2B.
◎ 英製牙 ─ BSW
● The recommended tap drill sizes indicated above are for JIS Class 2 Whitworth
threads.
● Generally, the tap drill sizes in column A are used for producing holes; When holes tend to be cut oversized, the tap drill sizes in column B should be selected. ● These tap drill sizes are in accordance with JIS B 1004-1966, while the nominal sizes
with a * mark are in accordance with BSW (Please refer to page 135).
◎ 管牙
●-1982
●●
0203-1982 Rp internal thread.
0203-1982 G internal thread.
The reccommended tap drill sizes indicated above are for JIS Class A PF threads.
◎ 管牙
● *1The above drill sizes are according to ANSI/ASME BI.20.1-1983 Pipe Threads,
General Purpose (inch) (partial listing).
● *2The above drill sizes are according to ANSI/ASME BI.20.3-1976 Pipe
Threads,
(inch) (partial listing).
◎ For Threads Using with Helical Coil Wire inserts
insert
manufacturers.
● The figures listed above are according to the data provided by helical coil wire
◎ 無溝絲攻下孔徑