This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX50S, 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 SI125AX50S
The AirTAC SI125 Standard Cylinder SI125AX50S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 50mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX50S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke50 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX50S
- 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 SI125AX50S
The AirTAC SI125AX50S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 50 mm stroke. It delivers 6136 N push force at 0.5 MPa. The direct replacement is the SAI125AX50S, which matches the original G1/2 port, M27x2 rod thread, and ISO 15552 mounting interface.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. This -A variant uses a SUS420J2 stainless piston rod, and the -S magnet works with legacy CS1-B/DS1-B sensors.
Airtac SI125 Standard Cylinder SI125AX50S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX50S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX50S |
| Bore size | Ø125 mm |
| Stroke | 50 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 SAI125AX50S 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 SAI125AX50S 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 SI125AX50S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×50 | 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 SI125AX50S Is Used
Heavy Press Clamping
Provides 6136 N of push force at 0.5 MPa to secure heavy metal stamping blanks in automated press lines.
Pallet Stopper Arms
Acts as a robust 125 mm bore stopper gate in high-mass conveyor systems, easily halting loaded pallets.
Injection Mold Ejection
Drives large ejection plates out of heavy industrial molds, utilizing the 32 mm SUS420J2 stainless rod.
Replacing the Airtac SI125 Standard Cylinder SI125AX50S with the SAI125AX50S
To replace the SI125AX50S, order the SAI125AX50S. Confirm the ISO 15552 mounting interface, 50 mm stroke, G1/2 port, and mounting accessory. The SAI family adds SAIL (air-released lock), SAIF (built-in 4M valve) and BSAI (clamp-lock) variants the SI lacked. A plain cylinder drifts on air loss; the cushion only decelerates, so use SAIL, BSAI, or an external rod lock for load holding. To size both ways: neighboring bores are 100 mm (3927 N [email protected]) and 160 mm (10053 N [email protected]). This 125 mm bore provides 6136 N push and 5734 N pull at 0.5 MPa, 8590 N at 0.7 MPa, and 1251 kgf max at 1.0 MPa. Speed is 30-500 mm/s.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX50S
- ✓ 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 SI125AX50S FAQ
Yes, the SI125AX50S is discontinued. The direct replacement is the SAI125AX50S. It is dimensionally interchangeable per ISO 15552, matching the 125 mm bore, 50 mm stroke, G1/2 port, and mounting fixtures.
The G1/2 port bore delivers 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, and 11045 N at 0.9 MPa. The theoretical max is 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX50S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX50S replacement — usually within 7-8 hours.