This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX35S, 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 SI125AX35S
The AirTAC SI125 Standard Cylinder SI125AX35S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 35mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX35S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke35 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX35S
- 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 SI125AX35S
The AirTAC SI125AX35S is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore, 35 mm stroke, and a SUS420J2 stainless steel piston rod. It delivers 6136 N push force at 0.5 MPa. AirTAC replaced this legacy unit with the SAI125AX35S, a direct upgrade retaining the exact ISO 15552 mounting interface, G1/2 port, and output force.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. This -S model includes a piston magnet for legacy CS1-B/DS1-B sensors; the SAI family also adds SAIL and BSAI lock variants absent in the SI line.
Airtac SI125 Standard Cylinder SI125AX35S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX35S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX35S |
| Bore size | Ø125 mm |
| Stroke | 35 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 SAI125AX35S 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 SAI125AX35S 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 SI125AX35S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×35 | 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 SI125AX35S Is Used
Heavy-Duty Pressing
Applies 6136 N of push force at 0.5 MPa for seating large bearings or assembling heavy machinery components.
Pallet Positioning
Uses the short 35 mm stroke and SUS420J2 stainless rod to index or clamp heavy pallets in humid washdown zones.
Stamping Operations
Delivers reliable impact force for product date coding or light stamping tasks within automated lines.
Replacing the Airtac SI125 Standard Cylinder SI125AX35S with the SAI125AX35S
To replace the SI125AX35S, order the SAI125AX35S. Confirm the ISO 15552 mounting interface, the 125 mm bore, the 35 mm stroke, the G1/2 air port, and your mounting accessory. The -A suffix specifies the SUS420J2 stainless rod, and -S confirms the magnet for legacy CS1-B/DS1-B switches. When sizing, note the 6136 N push force at 0.5 MPa; if you need less force, step down to a 100 mm bore offering 3927 N. Because a standard cylinder drifts without live air and the cushion only decelerates, use the SAIL or BSAI lock variant for load holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX35S
- ✓ 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 SI125AX35S FAQ
Yes, the SI125AX35S is discontinued. The direct replacement is the SAI125AX35S. It shares the same ISO 15552 mounting interface, 125 mm bore, 35 mm stroke, output force, G1/2 port, and SUS420J2 stainless rod.
The G1/2 port bore 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. The piston rod is 32 mm with an M27x2 thread.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX35S
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