About O-Rings
Handling of O-Rings
The watertightness of the pressure-resistant vessels and connectors we handle is maintained by O-rings.
O-rings are mainly made of Nitrile Butadiene Rubber (NBR) and function to withstand water pressure due to its elasticity.
The following precautions should be taken when handling O-rings.
(1)Check for foreign substances by tracing with your fingertips.
(2)Check the surface for cracks, scratches, and deformations (distorted or crushed areas).
(3)Apply grease the manufacturer recommends thinly and evenly to the surface of the entire circumference of the O-ring.
O-Ring Size and Hardness
The size of O-rings is defined by the wire diameter (W) and inner diameter (ID) as shown in the diagram below.
Also, the hardness of O-rings is mainly 70HS and 90HS.
About Screws
Among the equipment we handle, American-made products often use inch sizes, and British-made products often use mm sizes.
The two sizes may be present simultaneously, so please contact us if necessary.
Unified Screws
| Nominal Diameter | Outer Diameter of Screw | Number of Threads | |||
|---|---|---|---|---|---|
| Coarse Thread | Fine Thread | ||||
| Column 1 | Column 2 | inch | mm | UNC | UNF |
| No.0 | 0.0600 | 1.524 | 80 | ||
| No.1 | 0.0730 | 1.854 | 64 | 72 | |
| No.2 | 0.0860 | 2.184 | 56 | 64 | |
| No.3 | 0.0990 | 2.515 | 48 | 56 | |
| No.4 | 0.1120 | 2.845 | 40 | 48 | |
| No.5 | 0.1250 | 3.175 | 40 | 44 | |
| No.6 | 0.1380 | 3.505 | 32 | 40 | |
| No.8 | 0.1640 | 4.166 | 32 | 36 | |
| No.10 | 0.1900 | 4.826 | 24 | 32 | |
| No.12 | 0.2160 | 5.486 | 24 | 28 | |
| 1/4 | 0.2500 | 6.350 | 20 | 28 | |
| 5/16 | 0.3125 | 7.938 | 18 | 24 | |
| 3/8 | 0.3750 | 9.525 | 16 | 24 | |
| 7/16 | 0.4375 | 11.112 | 14 | 20 | |
| 1/2 | 0.5000 | 12.700 | 13 | 20 | |
| 9/16 | 0.5625 | 14.288 | 12 | 18 | |
| 5/8 | 0.6250 | 15.875 | 11 | 18 | |
| 11/16 | 0.6875 | 17.462 | |||
| 3/4 | 0.7500 | 19.050 | 10 | 16 | |
| 13/16 | 0.8125 | 20.638 | |||
| 7/8 | 0.8750 | 22.225 | 9 | 14 | |
| 15/16 | 0.9375 | 23.812 | |||
| 1 | 1.0000 | 25.400 | 8 | 12 | |
| Table of Thread Pitch Conversion | |
|---|---|
| Number of Threads | Pitch |
| (per 25.4mm) | (mm) |
| 100 | 0.2540 |
| 80 | 0.3175 |
| 72 | 0.3528 |
| 64 | 0.3969 |
| 60 | 0.4233 |
| 56 | 0.4536 |
| 48 | 0.5292 |
| 44 | 0.5773 |
| 40 | 0.6350 |
| 36 | 0.7056 |
| 32 | 0.7938 |
| 28 | 0.9071 |
| 27 | 0.9407 |
| 24 | 1.0583 |
| 20 | 1.2700 |
| 19 | 1.3368 |
| 18 | 1.4111 |
| 16 | 1.5875 |
| 14 | 1.8143 |
| 13 | 1.9538 |
| 12 | 2.1167 |
Metric Screws
| Nominal Diameter | Outer Diameter of Screw | Pitch | ||
|---|---|---|---|---|
| Column 1 | Column 2 | Column 3 | mm | |
| M1 | 1.000 | 0.25 | ||
| 0.2 | ||||
| M1.1 | 1.100 | 0.25 | ||
| 0.2 | ||||
| M1.2 | 1.200 | 0.25 | ||
| 0.2 | ||||
| M1.4 | 1.400 | 0.3 | ||
| 0.2 | ||||
| M1.6 | 1.600 | 0.35 | ||
| 0.2 | ||||
| M1.8 | 1.800 | 0.35 | ||
| 0.2 | ||||
| M2 | 2.000 | 0.4 | ||
| 0.25 | ||||
| M2.2 | 2.200 | 0.45 | ||
| 0.25 | ||||
| M2.5 | 2.500 | 0.45 | ||
| 0.35 | ||||
| M3 | 3.000 | 0.5 | ||
| 0.35 | ||||
| M3.5 | 3.500 | 0.6 | ||
| 0.35 | ||||
| M4 | 4.000 | 0.7 | ||
| 0.5 | ||||
| M4.5 | 4.500 | 0.75 | ||
| 0.5 | ||||
| M5 | 5.000 | 0.8 | ||
| 0.5 | ||||
| M5.5 | 5.500 | 0.5 | ||
| M6 | 6.000 | 1 | ||
| 0.75 | ||||
| M7 | 7.000 | 1 | ||
| 0.75 | ||||
| M8 | 8.000 | 1.25 | ||
| 1 | ||||
| 0.75 | ||||
| M9 | 9.000 | 1.25 | ||
| 1 | ||||
| 0.75 | ||||
| M10 | 10.000 | 1.5 | ||
| 1.25 | ||||
| 1 | ||||
| 0.75 | ||||
| M11 | 11.000 | 1.5 | ||
| 1 | ||||
| 0.75 | ||||
| M12 | 12.000 | 1.75 | ||
| 1.5 | ||||
| 1.25 | ||||
| 1 | ||||
| M14 | 14.000 | 2 | ||
| 1.5 | ||||
| 1.25 | ||||
| 1 | ||||
| M15 | 15.000 | 1.5 | ||
| 1 | ||||
| M16 | 16.000 | 2 | ||
| 1.5 | ||||
| 1 | ||||
| M17 | 17.000 | 1.5 | ||
| 1 | ||||
| M18 | 18.000 | 2.5 | ||
| 2 | ||||
| 1.5 | ||||
| 1 | ||||
| M20 | 20.000 | 2.5 | ||
| 2 | ||||
| 1.5 | ||||
| 1 | ||||
| M22 | 22.000 | 2.5 | ||
| 2 | ||||
| 1.5 | ||||
| 1 | ||||
| M24 | 24.000 | 3 | ||
| 2 | ||||
| 1.5 | ||||
| 1 | ||||
| M25 | 25.000 | 2 | ||
| 1.5 | ||||
| 1 | ||||