
PD PD
M2 Taps M3
Min Taps
Max Length of 74.1%74.1%
Length of engagement engagement=4.6mm On "middle" engagement class, 7H class can be chosen M4 in case of "L" engagement length. Internal threads made by roll taps are Engagement different from those made by cutting
Internal threads Taps classification taps on the shape of minor dimameter. Engagement Unit : mm
length D1 Unit : mm
Engagement External threads *Hole size for thread forming taps
| length classification | Drill size | Min | Max | M5 | |
| (ref.) |
S Short engagement length 4H 5H — S 1.5(mm) Min Max
Bored hole size 2.5 2.459 2.599 Taps
| M | Normal engagement length | 5H | 6H | 7H | 2.75 | 2.82 | ||
| 1.5 M 4.5(mm) | Engagement ratio |
92.4% 100% 74.1% Forming condition changes depending
L Long engagement length 6H 7H 8H 4.5 L(mm)
P=0.5mm on workpiece's Material and shape. D1 is minor diameter of JIS 6H(2nd Class) of internal threads Above is for customer's reference. M6 Taps
M8 Thread class of cutting taps Taps 【Pitch diameter】
| Internal threads | Class | PD tolerance | |
| Diameter of imaginary cylinder or cone | |||
| which makes equal the width of threads | ISO2 | 24μm〜 40μm |
and width of space between the threads M10 ISO2X 39μm〜 55μm Taps *Above shows the plus tolerance
ISO2 by setting PD basic size as "0". ISO2X M12 Width of Width of Taps threadsthreads Thread class of roll taps
| Width of space Width of space Class | PD tolerance | M1-M | |||
| between threadsbetween threads | μm〜 | μm | |||
| ISO2X | 64 | 76 | Taps | 7 | |
| Pitch Pitch | μ 〜 | μ | |||
| ISO3X | 76 | m | 89 m | ||
| diameterdiameter | |||||
| ISO2XISO2X *Above shows the plus tolerance | M9-M | ||||
| ISO3XISO3X by setting PD basic size as "0". | 24 | ||||
| Taps | |||||
| Basic size of pitch diameter | |||||
| 2.675mm | M25-M | ||||
| +50μm -50μm -100μm -150μm +100μm | +150μm | Taps | 48 | ||
| ← | For Unified | ||||
| ISO2X ISO3X 6g | Roll taps | threads | |||
| Taps |
| Tolerance of dies is the | ISO2 | ← | ||||
| target of external threads | Cutting taps | |||||
| ISO2X | For Whitworth | |||||
| Class of dies | threads |
| 6g | Solid dies | 6g external threads( | 〜 | ) | 6H internal threads( | 〜 | ) | Taps | ||
| -95 | -20 | 0 | 100 |
NR GRGR GP NP
For Pipe threads Relative position of PD tolerance area of external threads, internal threads, taps and gages. Taps
For Pg threads (–) ← Basic size of pitch diameter → (+) Taps 2.675mm
Unit : m Unit : m Ring gage pitch diameter (for external threads inspection) Plug gage pitch diameter (for internal threads inspection)
NR6g -105 〜 -95 GR6g -23 〜 -13 〜 〜
GP6H 2 10 NP6H 100 108
NR : NOT GO ring gage GP : GO plug gage GR : GO ring gage NP : NOT GO plug gage Unit : mm Unit : mm Accuracy of external threads Accuracy of internal threads
Major diameter Pitch diameter Minor diameter Major diameter Pitch diameter Minor diameter
6g 2.874〜2.980 2.580〜2.655 − 6H − 2.675〜2.775 2.459〜2.599