This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX5S, 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 SI125AX5S
The AirTAC SI125 Standard Cylinder SI125AX5S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 5mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX5S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke5 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX5S
- 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 SI125AX5S
The AirTAC SI125AX5S is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore, 5 mm stroke, and a SUS420J2 stainless steel rod. It delivers 6136 N push force at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125AX5S, which shares the same ISO 15552 mounting interface, bore, output, and accessories.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. Note that 5 mm is a nonstandard stroke below the typical range. The -S magnet supports legacy CS1-B/DS1-B sensors, while a plain cylinder needs an external rod lock for load holding.
Airtac SI125 Standard Cylinder SI125AX5S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX5S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX5S |
| Bore size | Ø125 mm |
| Stroke | 5 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 SAI125AX5S 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 SAI125AX5S 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 SI125AX5S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×5 | 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 SI125AX5S Is Used
Short-Stroke Clamping
Ideal for high-force clamping of heavy steel plates in machining fixtures, utilizing the 125 mm bore and 5 mm stroke for rapid, rigid holding.
Heavy Pressing
Provides 6136 N of precise downward pressing force at 0.5 MPa for seating large industrial bearings or bushings into housings.
Stub Ejection
Acts as a compact, powerful ejection pin in heavy-duty injection molding or stamping lines where minimal travel but massive push force is required.
Replacing the Airtac SI125 Standard Cylinder SI125AX5S with the SAI125AX5S
To replace the SI125AX5S, order the SAI125AX5S. Verify your ISO 15552 mounting interface, the G1/2 air port, and the M27x2 rod thread. The 5 mm stroke is nonstandard, so confirm exact end-of-travel positioning. Because this is a short-stroke high-force actuator, evaluate side-load and rod-bending risks carefully. Sizing both ways: a 100 mm bore offers 3927 N push at 0.5 MPa, while a 160 mm bore provides 10053 N. Remember that the air cushion only decelerates; it does not hold load on air loss. For locked positions, use an external pilot check valve or explore the SAIL or BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX5S
- ✓ 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 SI125AX5S FAQ
Yes, the SI125AX5S is discontinued. The direct replacement is the AirTAC SAI125AX5S. It is dimensionally interchangeable per ISO 15552, retaining the same 125 mm bore, 5 mm stroke, G1/2 port, and mounting interface, so it drops directly into existing fixtures.
This double-acting cylinder uses a G1/2 air port. The force output 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 maximum of 1251 kgf at 1.0 MPa. It operates at 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX5S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX5S replacement — usually within 7-8 hours.