This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125BX400, with the same bore, stroke, output force, port and mounting, so it fits the same application. The SAI replacement keeps the same ISO 15552 mounting interface, bore, stroke, output force and accessories, so it drops straight into existing fixtures. It is the current-production version of this cylinder with an upgraded piston seal.
Airtac SI125 Standard Cylinder SI125BX400
The AirTAC SI125 Standard Cylinder SI125BX400 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 400mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125BX400, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke400 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125BX400
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac SI125 Standard Cylinder SI125BX400
The AirTAC SI125BX400 is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore and 400 mm stroke. It delivers 6136 N push and 5734 N pull at 0.5 MPa, with a G1/2 air port and M27x2 rod thread. The direct replacement is the SAI125BX400, which matches the interface, bore, stroke, force, port and mounting. This SKU uses a SUS304 stainless steel rod (B option) for corrosion resistance, but lacks a magnet so it cannot accept a sensor.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. The family also adds SAIL, SAIF and BSAI lock variants. Note that a plain cylinder drifts without live air; use an external rod lock or pilot check valve for load holding.
Airtac SI125 Standard Cylinder SI125BX400 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125BX400 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125BX400 |
| Bore size | Ø125 mm |
| Stroke | 400 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2.0 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 500 mm/s |
| Cushion | Adjustable, 40 mm |
| Max standard stroke | Up to 1500 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI125BX400 carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
The SAI125BX400 produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI125 Standard Cylinder SI125BX400
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×400 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Legacy SI-family variants: SID (double rod), SIJ (adjustable stroke) — each maps to its SAI equivalent (SID→SAID, SIJ→SAIJ). Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B).
Where the Airtac SI125 Standard Cylinder SI125BX400 Is Used
Heavy Press Clamping
Provides 6136 N of clamping force at 0.5 MPa to secure large metal castings or heavy machinery frames during machining and press operations.
Robotic Material Transfer
Shifts substantial workpieces between conveyor lines, relying on the SUS304 stainless rod to resist moisture in wash-down areas.
Replacing the Airtac SI125 Standard Cylinder SI125BX400 with the SAI125BX400
To replace the SI125BX400, order the SAI125BX400. Confirm the ISO 15552 mounting interface, the 400 mm stroke, G1/2 port (PT/G/NPT thread options), and your specific mounting accessory (LB, FA, TC, etc.). Because this SKU lacks the -S magnet, it cannot support sensing; if position detection is needed, switch to a magnet-equipped SAI model and use current AirTAC switches. Sizing both ways: the 125 mm bore yields 6136 N push at 0.5 MPa (8590 N at 0.7 MPa), while the neighbouring 100 mm bore offers 3927 N at 0.5 MPa. For load holding on air loss, the cushion only decelerates; you must add an external rod lock, a pilot-operated check valve, or specify a SAIL/BSAI lock variant. Finally, at 400 mm stroke, prevent rod bending by guiding the load externally to avoid side-load forces.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125BX400
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI125 Standard Cylinder SI125BX400 FAQ
Yes, the SI125BX400 is discontinued. The direct replacement is the SAI125BX400. It is dimensionally interchangeable per ISO 15552, matching the 125 mm bore, 400 mm stroke, 6136 N force, G1/2 port and mounting fixtures.
This 125 mm bore cylinder has a G1/2 air port and M27x2 rod thread. The thrust is 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N push at 0.9 MPa, and a theoretical max of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125BX400
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