Page 695 - Yamawa_European_Catalogue_YEU21

17. Taps for Pipe Threads

Intro

JIS Pipe Taps
The pipe thread standard (JIS B 0202,0203) was revised in 1982 to meet ISO standard. In the same year, JIS B 4445 (straight pipe thread taps) SP
and JIS B 4446 (taper pipe thread taps) were also revised.
• A part of the pipe thread standard was revised in 1966 to meet ISO, but in the 1982 revision, the ISO standard was defined in the main
book of JIS and the old 1966 standard was defined in JIS Appendix. For Pipe Threads specified in the main book of JIS and JIS Appendix,
thread symbols are different but the nominal size 1/8 to 6 inch are same. In the 1998 revision, the contents of the main book of JIS and JIS
Appendix are not changed. SL
• ISO tap standard for pipe threads is different from the JIS tap standard in style, size and thread limit. Like the pipe thread standard, in
JIS tap standards for pipe threads, style, size and thread limits of ISO standard are adopted in the main book of JIS and those of old JIS
standard are in the JIS Appendix. For ISO standard (style and size), please refer to the next page.
• Thread limits of Rp and G taps are the same as the ISO standard. The thread limit of Rc taps is the same as the JIS class 2 of PT taps shown
in JIS Appendix because Rc is not specified in the ISO standard. Therefore, both Rc taps and PT taps can be used interchangeably. For the PO
relation between thread limit of internal threads and tap thread limit, please refer to the table below.
• Pipe Tap standard was revised in 1987. And tap designations shown in JIS Appendix were changed to PF taps for Parallel Pipe Thread, PT
taps for Taper Pipe Thread, and PS taps for Parallel Pipe Thread.
ST
Symbol of Pipe threads

Type Classifi cation Standard JIS (ISO) JIS Appendix
Internal Thread Rc PT
Taper Thread ROLL
External Thread R PT
Taper Thread JIS B 0203-1982
Internal Thread Rp PS
Parallel Thread
External Thread - -
G PF, A class
Internal Thread CARBIDE
- PF, B class
Parallel Thread Parallel Thread JIS B 0202-1982
G, A class PF, A class
Internal Thread
G, B class PF, B class
LONG
Relation between classification/engagement of pipe threads and taps

Kind of thread Classifi cation Main usage Type Engagement pipe taps
HAND
PS TAPS
Parallel Parallel internal thread
PS
(Rp) THL D1 D2 D
Basic diameter position
Internal EG (STI)
threads
Taper internal thread D
In connection of pipes, Taper D2 PT
Taper pipe parts and fl uid parts PT THL D1
pipe they are used mainly (Rc)
threads for the purpose of pressure
type joints. Taper internal thread SPECIAL
D THREADS,
D2
D1
t GAUGES
Pipe thread Taper a f S-PT
External PT
threads
(R) THREAD
Taper external thread
d d2 d1 MILLS
Internal PF Parallel internal thread
threads (G)
In connection of pipes, PF
Parallel pipe parts and fl uid parts, D1 D2 D DIES
pipe they are used mainly
threads for the purpose of
mechanical type joints. d
External PF d2 d1 Parallel external thread
threads (G)
CENTER
DRILLS
Technical
info

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