This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX400, 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 SI125AX400
The AirTAC SI125 Standard Cylinder SI125AX400 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 SAI125AX400, 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 → SAI125AX400
- 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 SI125AX400
The AirTAC SI125AX400 is a discontinued double-acting ISO 15552 profile cylinder featuring a 125 mm bore and 400 mm stroke. It delivers a thrust of 6136 N at 0.5 MPa. AirTAC replaced this legacy unit with the SAI125AX400, a direct replacement retaining the exact same ISO 15552 mounting interface, bore, stroke, output force, and G1/2 port.
The SAI125AX400 upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure and longer life. This SKU has no magnet (-S omitted), so it cannot accept a CS1-B/DS1-B sensor. It uses an SUS420J2 stainless rod (-A).
Airtac SI125 Standard Cylinder SI125AX400 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX400 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX400 |
| 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 SAI125AX400 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 SAI125AX400 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 SI125AX400
| 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 SI125AX400 Is Used
Heavy Stamp Press Feed
Drives robust 400 mm displacement cycles to feed thick sheet metal into stamping presses, utilizing the 6136 N thrust at 0.5 MPa.
Pallet Dispenser Pusher
Indexes heavy empty pallets along accumulation conveyors with reliable force, requiring external guides to manage the long 400 mm stroke.
Large Mold Actuation
Shifts substantial casting or molding tooling over 400 mm, benefiting from the SUS420J2 stainless rod for corrosion resistance in humid foundries.
Replacing the Airtac SI125 Standard Cylinder SI125AX400 with the SAI125AX400
To replace the SI125AX400, order the SAI125AX400. Verify your ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/2 air port, and the M27x2 rod thread. Because this SKU lacks the -S magnet, it cannot support position sensing; if switches are needed, select an SAI125AX400S. Sizing both ways: the 125 mm bore yields 6136 N push at 0.5 MPa (8590 N at 0.7 MPa), while a neighbouring 100 mm bore provides 3927 N. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external rod lock or pilot check valve, or specify the SAIL/BSAI lock variant. For the 400 mm stroke, use external guides to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX400
- ✓ 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 SI125AX400 FAQ
Yes, the SI125AX400 is discontinued. The direct replacement is the SAI125AX400. It is dimensionally interchangeable per ISO 15552, matching the bore, stroke, force, G1/2 port, and mounting fixtures.
The G1/2 port bore delivers a push force of 6136 N and pull of 5734 N at 0.5 MPa. At 0.7 MPa push is 8590 N, at 0.9 MPa it is 11045 N, and the theoretical max is 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX400
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX400 replacement — usually within 7-8 hours.