This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X312S, 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 SI125X312S
The AirTAC SI125 Standard Cylinder SI125X312S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 312mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X312S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke312 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X312S
- 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 SI125X312S
The AirTAC SI125X312S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 312mm stroke. It delivers 6136N push force at 0.5MPa via a G1/2 port. The direct replacement is the SAI125X312S, matching the interface, force and mounting.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure. The SAI family adds SAIL, SAIF and BSAI lock variants. This -S model uses CS1-B/DS1-B sensors.
Airtac SI125 Standard Cylinder SI125X312S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X312S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X312S |
| Bore size | Ø125 mm |
| Stroke | 312 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 SAI125X312S 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 SAI125X312S 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 SI125X312S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×312 | 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 SI125X312S Is Used
Heavy Pressing
Applies the 6136N push force at 0.5MPa for seating heavy bearings or forming thick metal plates.
Pallet Handling
Moves loaded pallets along conveyors where the 312mm stroke provides the required reach.
Clamp Fixtures
Secures large workpieces in machining centers using the robust 125mm bore power.
Replacing the Airtac SI125 Standard Cylinder SI125X312S with the SAI125X312S
To replace the SI125X312S, order the SAI125X312S. Verify the ISO 15552 mounting interface, 312mm stroke, G1/2 port and magnet. Neighbouring bores: 100mm gives 3927N push, while 160mm gives 10053N at 0.5MPa. Note that 312mm is a nonstandard stroke; at this length use external guides to prevent rod bending and side loads. A plain cylinder drifts on air loss; for load holding use the SAIL or BSAI lock variant, or an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X312S
- ✓ 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 SI125X312S FAQ
Yes, the SI125X312S is discontinued. The direct replacement is the SAI125X312S. It matches the ISO 15552 mounting interface, 125mm bore, 312mm stroke, force, G1/2 port and accessories.
The G1/2 port bore delivers 6136N push and 5734N pull at 0.5MPa, 8590N push at 0.7MPa, 11045N at 0.9MPa, and a max force of 1251kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X312S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X312S replacement — usually within 7-8 hours.