This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX40S, 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 SI125AX40S
The AirTAC SI125 Standard Cylinder SI125AX40S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 40mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX40S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke40 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX40S
- 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 SI125AX40S
The AirTAC SI125AX40S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 40 mm stroke. Featuring a SUS420J2 stainless piston rod and a built-in magnet for CS1-B/DS1-B switches, it delivers 6136 N push force at 0.5 MPa. AirTAC replaced this legacy unit with the SAI125AX40S, a direct upgrade sharing the exact ISO 15552 mounting interface, G1/2 port, and 1251 kgf maximum force.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. Note that a plain cylinder drifts without live air; for load holding, explore the SAIL lock or BSAI clamp-lock variants the SI line lacked.
Airtac SI125 Standard Cylinder SI125AX40S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX40S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX40S |
| Bore size | Ø125 mm |
| Stroke | 40 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 SAI125AX40S 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 SAI125AX40S 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 SI125AX40S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×40 | 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 SI125AX40S Is Used
Heavy Stamp Pressing
Applies 6136 N of thrust at 0.5 MPa for short-stroke stamping, forming, and pressing tasks in metal fabrication.
Pallet Stopper Gate
Acts as a robust 125 mm bore blocking gate in high-mass conveyor lines, using its 313 kg vertical lift capacity for heavy loads.
Injection Mold Clamping
Provides reliable high-force mold holding with the SUS420J2 stainless rod option, resisting moisture in humid production environments.
Replacing the Airtac SI125 Standard Cylinder SI125AX40S with the SAI125AX40S
To replace your SI125AX40S, order the SAI125AX40S. It drops right into existing fixtures because the ISO 15552 interface, 125 mm bore, 40 mm stroke, M27x2 rod thread, and G1/2 port are unchanged. Keep the -S magnet for current AirTAC switches and the -A SUS420J2 stainless rod for corrosion resistance. If you need more force, the neighboring 160 mm bore offers 10053 N push at 0.5 MPa; if less is acceptable, the 100 mm bore provides 3927 N. Because the 40 mm stroke is short, side-load risks are minimal, but always verify guide alignment. A standard cylinder does not hold load on air loss—the cushion only decelerates—so add a pilot check valve or specify the SAIL/BSAI lock variant for suspended loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX40S
- ✓ 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 SI125AX40S FAQ
Yes, the AirTAC SI125AX40S is discontinued. The direct replacement is the SAI125AX40S. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 40 mm stroke, G1/2 port, and mounting interface.
This 125 mm bore cylinder uses a G1/2 air port. It delivers 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 maximum of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX40S
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